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1: Scand J Immunol 2000 Aug;52(2):138-47
Characterization of murine dendritic cells derived from adherent blood
mononuclear cells in vitro.
Agger R, Petersen MS, Toldbod HE, Holtz S, Dagnaes-Hansen F, Johnsen BW, Bolund L, Hokland M.
Department of Medical Microbiology and Immunology, University of Aarhus, Aarhus, Denmark.
[email protected]
The therapeutic potential of dendritic cells loaded with tumour antigens for the induction of effective immune
responses against cancer is currently being tested in numerous clinical trials. In most cases, the dendritic cells are
generated in vitro from peripheral blood monocytes. Many aspects of dendritic cell-based vaccination have not yet
been examined in detail, and homologous mouse model systems may prove very valuable for optimizing clinical
procedures. In the murine system, however, dendritic cells are usually isolated from either lymphoid tissues or bone
marrow cultures. To date, murine monocyte-derived dendritic cells have been described only sporadically. Here, we
describe a culture system for the generation of murine dendritic cells from adherent peripheral blood mononuclear
cells by culturing in the presence of granulocyte-macrophage colony stimulating factor and interleukin-4. After 7
days of culture the nonadherent cells were harvested from the cultures. Most of these cells exhibited well-accepted
characteristics of mature dendritic cells (e.g. veiled appearance, high expression of major histocompatibility
complex class II and CD86) and stimulated vigorous proliferation of allogeneic T cells in a primary mixed leucocyte
reaction following stimulation with bacterial lipopolysaccharide. Interestingly, staining the cells for expression of
the putative antigen-uptake receptor DEC-205 revealed a distinct bimodal distribution.
Free as elsevier
J Immunol Methods 2000 May 26;239(1-2):95-107
A two-step culture method starting with early growth factors permits
enhanced production of functional dendritic cells from murine splenocytes.
Berthier R, Martinon-Ego C, Laharie AM, Marche PN.
Laboratoire Immunochimie, CEA-G, DBMS/ICH, INSERM U238, Universit inverted question marke Joseph
Fourier, 17, rue des Martyrs, 38054 Cedex 9, Grenoble, France. [email protected]
Dendritic cells (DC) are professional antigen presenting cells (APC) able to activate naive T cells and initiate the
immune response. They are present in most tissues at very low concentrations and are difficult to isolate. DC can be
obtained in larger numbers by their propagation from progenitors present in blood, bone marrow and spleen.
However, biochemical studies and biological analysis of DC functions require very large numbers of these cells. In
this paper, we described a two-step culture system using unfractionated splenocytes from BALB/c mice as a source
of DC progenitors. The proliferative capacity of the progenitors is amplified in the first step of the culture (day 0-6)
using different combinations of early acting cytokines combined or not with granulocyte-macrophage CSF (GMCSF). The second step of the culture starts at day 6 with the removal of early growth factors in order to allow the
differentiation and final maturation of DC during 2-3 weeks of culture with flt-3 ligand (flt-3L) and GM-CSF. The
addition of Stem Cell Factor (SCF) or IL-6 to the standard combination of flt-3L+/-GM-CSF produces a large
increase in the proliferation of GM and DC progenitors (28 times and 11 times respectively) in the first step of the
culture. This proliferative wave of DC progenitors is followed by the production of a high percentage of immature
and mature DC in flt-3L+GM-CSF stimulated cultures. The best combination of early cytokines in terms of
proliferative activity and subsequent level of DC production was flt-3L+IL-6+GM-CSF, which permitted the
generation of 1 to 2x10(9) DC from one single spleen. Using this growth factor cocktail, a mixture of immature (2/3)
and mature (1/3) DC was produced until day 14 of culture, and levels of MHC class II and costimulatory molecules
(CD40, B7.2) increased between 2 and 4 weeks of incubation, or within 2 days when stimulated by IL-4 or LPS. The
splenic DC produced after 2 weeks of culture are fully functional, exhibiting a high capacity of endocytosis when
immature, a strong stimulatory reactivity in mixed leukocyte reaction and consistently producing high levels of
bioactive IL-12 p70 after CD 40 ligation in the presence of LPS between 13 and 43 days of culture.
Microbiol Immunol 2002;46(1):23-8
Immunogenicity of a recombinant MVA and a DNA vaccine for Japanese
encephalitis virus in swine.
Nam JH, Cha SL, Cho HW.
Department of Virology, Korean National Institute of Health, Eunpyung-Gu, Seoul.
We previously reported that mice immunized with recombinant modified vaccinia virus Ankara (MVA) encoding
Japanese encephalitis virus (JEV) prM and E genes were completely protected against JEV challenge (Nam, J.H.,
Wyatt, L.S., Chae, S.L., Cho, H.W., Park, Y.K., Moss, B. Vaccine 1999,17: 261-268). In this study, we examined
the immunogenicity in swine of this recombinant MVA (vJH9) or a DNA vaccine (pcJH-1) expressing the same
JEV genes. Although the booster effect in mice with a combination of vJH9, pcJH-1 and inactivated JEV
commercial vaccine was not apparent by measuring JEV antibodies, the recombinant MVA vaccine (vJH9) and the
DNA vaccine (pcJH-l) efficiently produced neutralizing antibodies in swine and 2 doses of each showed a booster
effect in mice and swine. Therefore, both vJH9 and pcJH-1 are good candidates for a second generation JEV
vaccine.
Crit Rev Biochem Mol Biol 2002;37(1):29-54
DNA vaccine against malaria: a long way to go.
Tuteja R.
International Centre for Genetic Engineering and Biotechnology, New Delhi. [email protected]
Vaccination is the attempt to mimic certain aspects of an infection for the purpose of causing an immune response
that will protect the individual from that infection. Malaria, a disease responsible for immense human suffering, is
caused by infection with Plasmodium spp. parasites, which have a very complex life cycle--antigenically unique
stages infect different tissues of the body. It is a parasitic disease for which no successful vaccine has been
developed so far, despite considerable efforts to develop a subunit vaccine that offers protective immunity. Due to
the spread of drug-resistant malaria, efforts to develop an effective vaccine have become increasingly critical. DNA
vaccination provides a stable and long-lived source of protein vaccine capable of inducing both antibody- and cellmediated immune responses to a wide variety of antigens. Injected DNA enters the cells of the host and makes the
protein, which triggers the immune response. According to present needs, the flexibility of DNA vaccine technology
permits the combination of multiple antigens from both the preerythrocytic and erythrocytic stages of malaria
parasite. DNA vaccines with genes coding for different antigenic parts of malaria proteins have been created and
presently some of these are undergoing field trials. The results from these trials will help to determine the likelihood
of success of this technology in humans. This review presents an update of the studies carried out in malaria using
DNA vaccine approach, the challenges, and the future prospects.
Curr Mol Med 2001 May;1(2):217-43
DNA vaccines.
Reyes-Sandoval A, Ertl H C.
The Wistar Institute, Philadelphia, PA 19104, USA.
Within the last decade bacterial plasmids encoding foreign antigens have revolutionized vaccine design. Although
no DNA vaccine has yet been approved for routine human or veterinary use, the potential of this vaccine modality
has been demonstrated in experimental animal models. Plasmid DNA vaccination has shown efficacy against viral,
bacterial and parasitic infections, modulated the effects of autoimmune and allergic diseases and induced control
over cancer progression. With a better understanding of the basic immune mechanisms that govern induction of
protective or curative immune responses, plasmid DNA vaccines and their mode of delivery are continuously being
optimized. Because of the simplicity and versatility of these vaccines, various routes and modes of delivery are
possible to engage the desired immune responses. These may be T or B effector cell responses able to eliminate
infectious agents or transformed cells. DNA vaccines may also induce an immunoregulatory/modulatory or
immunosuppressive (tolerizing) response that interferes with the differentiation, expansion or effector functions of B
and T cells. In this sense a DNA vaccine may be thought of as a 'negative' vaccine. Pre-clinical and initial smallscale clinical trials have shown DNA vaccines in either of these modes to be safe and well tolerated. Although DNA
vaccines induce significant immune responses in small animal trials their efficacy in humans has so far been less
promising thus necessitating additional optimizations of this novel vaccine approach.
Immunol Lett 2002 Apr 1;81(1):13-24
A DNA vaccine encoding the 42 kDa C-terminus of merozoite surface protein
1 of Plasmodium falciparum induces antibody, interferon-gamma and
cytotoxic T cell responses in rhesus monkeys: immuno-stimulatory effects of
granulocyte macrophage-colony stimulating factor.
Kumar S, Villinger F, Oakley M, Aguiar JC, Jones TR, Hedstrom RC, Gowda K, Chute J, Stowers A, Kaslow
DC, Thomas EK, Tine J, Klinman D, Hoffman SL, Weiss WW.
Malaria Program, Naval Medical Research Center, 20910, Silver Spring, MD, USA
We have constructed a DNA plasmid vaccine encoding the C-terminal 42-kDa region of the merozoite surface
protein1 (pMSP1(42)) from the 3D7 strain of Plasmodium falciparum (Pf3D7). This plasmid expressed recombinant
MSP1(42) after in vitro transfection in mouse VM92 cells. Rhesus monkeys immunized with pMSP1(42) produced
antibodies reactive with Pf3D7 infected erythrocytes by IFAT, and by ELISA against yeast produced MSP1(19)
(yMSP1(19)). Immunization also induced antigen specific T cell responses as measured by interferon-gamma
production, and by classical CTL chromium release assays. In addition, immunization with pMSP1(42) primed
animals for an enhanced antibody response to a subsequent boost with the recombinant yMSP1(19). We also
evaluated Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) as an adjuvant for pMSP1(42.) We tested
both rhesus GM-CSF expressed from a DNA plasmid, and E. coli produced recombinant human GM-CSF. Plasmids
encoding rhesus GM-CSF (prhGM-CSF) and human GM-CSF (phuGM-CSF) were constructed; these plasmids
expressed bio-active recombinant GMCSF. Co-immunization with a mixture of prhGM-CSF and pMSP1(42)
induced higher specific antibody responses after the first dose of plasmid, but after three doses of DNA monkeys
immunized with or without prhGM-CSF had the same final antibody titers and T cell responses. In comparison,
rhuGM-CSF protein did not lead to accelerated antibody production after the first DNA dose. However, antibody
titers were maintained at a slightly higher level in monkeys receiving GM-CSF protein, and they had a higher
response to boosting with recombinant MSP1(19). The GM-CSF plasmid or protein appears to be less potent as an
adjuvant in rhesus monkeys than each is in mice, and more work is needed to determine if GM-CSF can be a useful
adjuvant in DNA vaccination of primates.
Nurse Pract 2002 Jan;27(1):53-9; quiz 60-1
Advances DNA vaccines.
Simmerman JM.
US Centers for Disease Control and Prevention, National Center for Infectious Diseases, International Emerging
Infections Program, Bangkok, Thailand.
Extraordinary advances in biotechnology make DNA vaccines the most promising area of vaccinology. This article
reviews the public health impact of vaccines in the 20th century, summarizes immunologic concepts, and updates
the status of DNA vaccine development and its impact on clinical practice.
Naturwissenschaften 2001 Dec;88(12):504-13
DNA vaccines.
Gregersen JP.
Chiron Behring GmbH, Postfach 1630, 35006 Marburg, Germany. [email protected]
Immunization by genes encoding immunogens, rather than with the immunogen itself, has opened up new
possibilities for vaccine research and development and offers chances for new applications and indications for future
vaccines. The underlying mechanisms of antigen processing, immune presentation and regulation of immune
responses raise high expectations for new and more effective prophylactic or therapeutic vaccines, particularly for
vaccines against chronic or persistent infectious diseases and tumors. Our current knowledge and experience of
DNA vaccination is summarized and critically reviewed with particular attention to basic immunological
mechanisms, the construction of plasmids, screening for protective immunogens to be encoded by these plasmids,
modes of application, pharmacokinetics, safety and immunotoxicological aspects. DNA vaccines have the potential
to accelerate the research phase of new vaccines and to improve the chances of success, since finding new
immunogens with the desired properties is at least technically less demanding than for conventional vaccines.
However, on the way to innovative vaccine products, several hurdles have to be overcome. The efficacy of DNA
vaccines in humans appears to be much less than indicated by early studies in mice. Open questions remain
concerning the persistence and distribution of inoculated plasmid DNA in vivo, its potential to express antigens
inappropriately, or the potentially deleterious ability to insert genes into the host cell's genome. Furthermore, the
possibility of inducing immunotolerance or autoimmune diseases also needs to be investigated more thoroughly, in
order to arrive at a well-founded consensus, which justifies the widespread application of DNA vaccines in a healthy
population.
Mol Immunol 2002 Mar;38(11):803-16
GPI-anchoring of GM-CSF results in active membrane-bound and partially
shed cytokine.
Poloso NJ, Nagarajan S, Mejia-Oneta JM, Selvaraj P.
Department of Pathology and Laboratory Medicine, School of Medicine, Emory University, 1639 Pierce Drive,
Woodruff Memorial Building, Room 7309, 30322, Atlanta, GA, USA
Granulocyte-macrophage colony-stimulating factor (GM-CSF) can induce the generation and activation of dendritic
cells (DCs), the most potent of antigen presenting cells (APCs). Tumors secreting GM-CSF have been shown to
induce strong anti-tumor immune responses. In this report, we have constructed a glycosylphosphatidyl-inositol
(GPI) anchored form of GM-CSF (GPI-GM-CSF). This protein subsequently was found expressed on the cell
membrane and sensitive to phosphatidyl-inositol-specific phospholipase C (PIPLC), confirming that it is GPIanchored. However, GM-CSF was also found in the culture supernatant of cells expressing GPI-GM-CSF. Inhibition
studies using brefeldin A and para-formaldehyde fixation revealed that GM-CSF found in the supernatant was not
secreted, but due to shedding or proteolytic cleavage. Accumulation of GM-CSF in the media from isolated
membranes was time and temperature-dependent. The released portion represented 10-15% of all membrane-bound
GM-CSF after 72h under culture conditions. GPI-GM-CSF retained functional activity to induce bone marrow cell
proliferation and administration of GPI-GM-CSF expressing membranes induced the generation of DCs in vivo.
These results demonstrate that GPI-anchored GM-CSF retains all functional activity of native GM-CSF while
gaining the ability to attach to cell membranes. The ability of GPI-GM-CSF to be expressed on membranes and be
partially released, can possibly lead to formation of a cytokine gradient, while retaining ability to target associated
membrane antigens to DCs. This novel form of GM-CSF may have wide range of clinical applicability.
J Immunol Methods 2002 Mar 1;261(1-2):49-63
Generation of functional and mature dendritic cells from cord blood and bone
marrow CD34(+) cells by two-step culture combined with calcium ionophore
treatment.
Liu A, Takahashi M, Narita M, Zheng Z, Kanazawa N, Abe T, Nikkuni K, Furukawa T, Toba K, Fuse I,
Aizawa Y.
First Department of Internal Medicine, Faculty of Medicine, Niigata University, Niigata, Japan
The object of this study is to explore a culture method to generate a large number of functional and mature dendritic
cells (DC) from human CD34(+) hematopoietic progenitor cells. In the present study, we used a two-step method
combined with calcium ionophore to induce DC from cord blood (CB) or normal human bone marrow (BM)
CD34(+) progenitor cells. The two-step method consists of 10 days of first step culture for the expansion and
proliferation of CD34(+) hematopoietic progenitor cells in the presence of SCF, IL-3, IL-6, G-CSF, and 7--11 days
of second step culture for the induction of DC in the presence of GM-CSF, IL-4 and TNF-alpha. By the two-step
culture, total nucleated cells were increased 208plus minus66 (meanplus minusSD, n=13), or 94plus minus29 (n=5)fold in the culture of CB or BM cells, respectively, compared with the number of CD34(+) cells at the time of
starting culture. Out of the total nucleated cells, 23plus minus10.4% of cells in CB cell culture and 25plus minus5%
of cells in the BM cell culture acquired DC characteristic phenotypes, which were marked expressions of CD1a,
HLA-DR, co-stimulatory molecules such as CD80, CD40, and adhesion molecule such as CD58. In allogeneic
mixed leukocyte reaction (MLR), two-step cultured cells showed potent allo-stimulatory capacity. With this twostep culture, the absolute number of CD1a(+) cells that co-expressed HLA-DR, CD80, CD40 and CD58 was
enhanced approximately 3 times in CB cell culture and 1.9 times in BM cell culture, compared with the commonly
used one-step culture method for the generation of DC from CD34(+) cells using SCF, GM-CSF and TNF-alpha.
However, on these DC generated in the two-step culture, the expressions of co-stimulatory molecule CD86 and
mature DC marker CD83 were not sufficient. By the treatment of two-step cultured cells with calcium ionophore
agent (A23187), the expression of co-stimulatory molecules such as CD86 and CD80 (especially CD86) was upregulated. Besides, the expression of mature DC marker CD83 was remarkably induced by treatment with A23187
for a short duration (24 h). Consistent with the up-regulation of surface molecules CD86, CD80 and CD83, the twostep cultured cells treated with A23187 also showed a stronger allo-stimulatory capacity compared with the cells
without A23187 treatment. In conclusion, the present study demonstrated that the two-step culture method
effectively improved the yield of CD1a(+) DC generated from CD34(+) cells, and the phenotypes and functions of
these CD1a(+) DC could be enhanced efficiently by treatment with a calcium ionophore agent.
Transplant Proc 2001 Nov-Dec;33(7-8):3814-5
Dendritic cells, generated in vitro, are immunocompetent and very useful in
the induction of specific cytotoxic T lymphocyte activity.
Hasel T, Yoshimura R, Wada S, Chargui J.
Immunology 2001 Oct;104(2):175-84
Porcine dendritic cells generated in vitro: morphological, phenotypic and
functional properties.
Carrasco CP, Rigden RC, Schaffner R, Gerber H, Neuhaus V, Inumaru S, Takamatsu H, Bertoni G,
McCullough KC, Summerfield A.
Institute of Virology and Immunoprophylaxis, Mittelhausern, Switzerland.
Despite the central role that dendritic cells (DC) play in immune regulation and antigen presentation, little is known
about porcine DC. In this study, two sources of DC were employed. Bone marrow haematopoietic cell-derived DC
(BM-DC) were generated using granulocyte-macrophage colony-stimulating factor (GM-CSF) in the presence or
absence of tumour necrosis factor-alpha (TNF-alpha). Monocyte-derived DC (Momicron-DC) were generated with
GM-CSF and interleukin-4 (IL-4). In both systems, non-adherent cells developed with dendritic morphology,
expressing high levels of major histocompatibility complex (MHC) class II. The presence of TNF-alpha increased
the BM-DC yield, and enhanced T-cell stimulatory capacity. Both BM-DC and Momicron-DC expressed the panmyeloid marker SWC3, as well as CD1 and CD80/86, but were also CD14+ and CD16+. The CD16 molecule was
functional, acting as a low-affinity Fc receptor. In contrast, the CD14 on DC appeared to differ functionally from
monocyte CD14: attempts to block CD14, in terms of lipopolysaccharide (LPS)-induced procoagulant activity
(PCA), failed. The use of TNF-alpha or LPS for DC maturation induced up-regulation of MHC class II and/or
CD80/86, but also CD14. Allogeneic mixed leucocyte reactions and staphylococcal enterotoxin B antigen
presentation assays demonstrated that these DC possessed potent T-cell stimulatory capacity. No T helper cell
polarization was noted. Both the BM-DC and the Momicron-DC induced a strong interferon-gamma and IL-4
response. Taken together, porcine DC generated in vitro possess certain characteristics relating them to DC from
other species including humans, but the continued presence of CD14 and CD16 on mature and immature porcine DC
was a notable difference.
J Immunol 2002 Feb 15;168(4):1704-9
Microbial compounds selectively induce Th1 cell-promoting or Th2 cellpromoting dendritic cells in vitro with diverse th cell-polarizing signals.
de Jong EC, Vieira PL, Kalinski P, Schuitemaker JH, Tanaka Y, Wierenga EA, Yazdanbakhsh M,
Kapsenberg ML.
Department of Cell Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
[email protected]
Upon microbial infection, specific Th1 or Th2 responses develop depending on the type of microbe. Here, we
demonstrate that different microbial compounds polarize the maturation of human myeloid dendritic cells (DCs) into
stably committed Th1 cell-promoting (DC1) or Th2 cell-promoting (DC2) effector DCs that polarize Th cells via
different mechanisms. Protein extract derived from the helminth Schistosoma mansoni induced the development of
DC2s that promote the development of Th2 cells via the enhanced expression of OX40 ligand. Likewise, toxin from
the extracellular bacterium Vibrio cholerae induced development of DC2s as well, however, via an OX40 ligandindependent, still unknown mechanism. In contrast, toxin from the intracellular bacterium Bordetella pertussis
induced the development of DC1s with enhanced IL-12 production, which promotes a Th1 cell development.
Poly(I:C) (dsRNA, mimic for virus) induced the development of extremely potent Th1-inducing DC1, surprisingly,
without an enhanced IL-12 production. The obtained DC1s and DC2s are genuine effector cells that stably express
Th cell-polarizing factors and are unresponsive to further modulation. The data suggest that the molecular basis of
Th1/Th2 polarization via DCs is unexpectedly diverse and is adapted to the nature of the microbial compounds.
J Immunol 2002 Jan 15;168(2):537-40
Cutting edge: Th2 response induction by dendritic cells: a role for CD40.
MacDonald AS, Straw AD, Dalton NM, Pearce EJ.
Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY
14853, USA.
We investigated the influence of dendritic cell (DC) CD40 expression on Th2 and Th1 development by in vivo
transfer of Ag-pulsed bone marrow-derived DC generated from wild-type (WT) or CD40(-/-) mice. Contrary to
expectation, CD40(-/-) DC primed with Ag that inherently induce a Th2 response (soluble egg Ag from Schistosoma
mansoni) failed to induce a Th2 response or any compensatory Th1 response, whereas CD40(-/-)DC primed with Ag
that inherently induce a Th1 response (Propionibacterium acnes) generated a competent Th1 response. Thus, DC
expression of CD40 is a prerequisite for initiation of Th2, but not Th1, responses by these Ag. Consistent with this,
CD154(-/-) mice, unlike WT mice, failed to mount a Th2 response when directly injected with schistosome eggs but
mounted a normal Th1 response after challenge with P. acnes. CD40-CD154 interaction can therefore play a major
role in Th2 response induction.
Parasite Immunol 2001 Dec;23(12):627-32
Defect of protective immunity to Schistosoma mansoni infection in Mongolian
gerbils involves limited recruitment of dendritic cells in the vaccinated skin.
Sato H, Kamiya H.
Department of Parasitology, Hirosaki University School of Medicine, Hirosaki, Japan.
In Mongolian gerbils, Meriones unguiculatus, the attenuated Schistosoma mansoni vaccine, is known to induce
marginal or no resistance to a homologous infection. To clarify the base of defective acquisition of the resistance,
we have focused on the induction phase of protective immunity to S. mansoni, i.e. cellular responses in the skin and
skin-draining lymph nodes (SLN). Percutaneous exposure to normal or ultraviolet (18mJ/cm2)-attenuated cercariae
induced comparable increases in SLN leucocyte counts, in contrast to other attenuated schistosome vaccine models
in rodents where attenuated parasites induce more notable increases in SLN leucocyte counts than normal ones.
Using serial sections, it was demonstrated that greater numbers of attenuated larvae remained for a longer period in
the exposed skin than normal ones. Correlated with cellular responses in the SLN, attenuated and normal
schistosomes elicited a comparable degree of response of epidermal Langerhans' cells/putative dermal dendritic cells
that were visualized by immunohistochemistry using a monoclonal antibody to a gerbil major histocompatibility
complex class II molecule (HUSM-M.g.30). It is speculated that in Mongolian gerbils limited recruitment of
dendritic cells around attenuated S. mansoni larvae, at least partially, contribute to defective induction of protective
immunity by the attenuated vaccine.
J Immunol 2001 Aug 15;167(4):1982-8
CD8- dendritic cell activation status plays an integral role in influencing Th2
response development.
MacDonald AS, Straw AD, Bauman B, Pearce EJ.
Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY
14853, USA.
Whether dendritic cells (DC) play a passive or active role in Th2 response induction is poorly understood. In this
study, we show that CD8- DC pulsed with Th2-polarizing Ag (soluble egg Ag (SEA)) from Schistosoma mansoni
potently stimulate Th2 responses in vivo and in vitro while failing to undergo a conventional maturation process.
Thus, in contrast to DC pulsed with the Th1 response inducing Ag Propionebacterium acnes, SEA-exposed DC
exhibit a phenotype that is most similar to that of immature DC, failing to up-regulate expression of CD40, CD54,
CD80, CD86, or OX40L; producing no detectable IL-4, IL-10, or IL-12; and displaying only a minor increase in
MHC class II expression. Importantly, in vitro derived DC exposed to SEA were phenotypically similar to CD8- DC
isolated from active S. mansoni infection. By discriminating between different types of pathogen and responding
appropriately, CD8- DC play a major role in the decision process to mount either a Th1 or Th2 response.
J Exp Med 2001 May 21;193(10):1135-47
Role of the parasite-derived prostaglandin D2 in the inhibition of epidermal
Langerhans cell migration during schistosomiasis infection.
Angeli V, Faveeuw C, Roye O, Fontaine J, Teissier E, Capron A, Wolowczuk I, Capron M, Trottein F.
Centre d'Immunologie et de Biologie Parasitaire, Institut National de la Sante et de la Recherche Medicale
(INSERM) U547, Lille, France.
Epidermal Langerhans cells (LCs) play a key role in immune defense mechanisms and in numerous immunological
disorders. In this report, we show that percutaneous infection of C57BL/6 mice with the helminth parasite
Schistosoma mansoni leads to the activation of LCs but, surprisingly, to their retention in the epidermis. Moreover,
using an experimental model of LC migration induced by tumor necrosis factor (TNF)-alpha, we show that parasites
transiently impair the departure of LCs from the epidermis and their subsequent accumulation as dendritic cells in
the draining lymph nodes. The inhibitory effect is mediated by soluble lipophilic factors released by the parasites
and not by host-derived antiinflammatory cytokines, such as interleukin-10. We find that prostaglandin (PG)D2, but
not the other major eicosanoids produced by the parasites, specifically impedes the TNF-alpha-triggered migration
of LCs through the adenylate cyclase-coupled PGD2 receptor (DP receptor). Moreover, the potent DP receptor
antagonist BW A868C restores LC migration in infected mice. Finally, in a model of contact allergen-induced LC
migration, we show that activation of the DP receptor not only inhibits LC emigration but also dramatically reduces
the contact hypersensitivity responses after challenge. Taken together, we propose that the inhibition of LC
migration could represent an additional stratagem for the schistosomes to escape the host immune system and that
PGD2 may play a key role in the control of cutaneous immune responses.
: Immunol Today 1999 Dec;20(12):561-7
T-cell priming by type-1 and type-2 polarized dendritic cells: the concept of a
third signal.
Kalinski P, Hilkens CM, Wierenga EA, Kapsenberg ML.
Parasite Immunol 1998 Jul;20(7):337-43
Accelerated influx of dendritic cells into the lymph nodes draining skin sites
exposed to attenuated cercariae of Schistosoma mansoni in guinea-pigs.
Sato H, Kamiya H.
Department of Parasitology, Hirosaki University School of Medicine, Japan.
We compared temporal changes in the cell composition of the skin-draining lymph nodes (SLN) in guinea-pigs
exposed percutaneously to normal or attenuated cercariae of Schistosoma mansoni. Different populations were
analysed by flow cytometry of double-stained cells by monoclonal antibodies to the major histocompatibility
complex class II molecule and lymph node cells of guinea-pigs. Exposure to S. mansoni caused a marked increase in
the proportion of B cells and dendritic cells (DC) on day 2, reaching a peak number on day 4. These changes were
comparable in both infected and vaccinated animals exposed to normal or attenuated parasites, respectively. Total
number of DC, however, showed different kinetics; in infected animals, the number peaked on day 2 and then
gradually declined, whereas it reached a higher peak on day 4 in vaccinated animal. Daily injection of bromodeoxyuridine after exposure to the parasite reduced the total number of DC in the SLN on day 4. A reduction in DC
counts in the contralateral side SLN was also evident in vaccinated animals. Our results indicate that a significant
number of newly formed DC are recruited to the skin by 4th day of vaccination, followed by increased efflux to the
SLN. It is possible that retention of attenuated S. mansoni in the skin may cause accelerated recruitment of newly
formed DC from the bone marrow, and facilitate transport and processing of antigens highly expressed on attenuated
parasites.
Hybridoma 1997 Dec;16(6):529-36
Production of murine monoclonal antibodies to guinea pig leukocytes and
immunohistochemistry of guinea pig skin exposed to Schistosoma mansoni.
Sato H, Inaba T, Kamiya H.
Department of Parasitology, Hirosaki University School of Medicine, Japan.
Using histochemical ATPase-staining of the guinea pig epidermal sheet, we have demonstrated remarkable
accumulations of ATPase-positive cells after exposure to attenuated Schistosoma mansoni cercariae. To characterize
further the cells accumulating in the skin after exposure to S. mansoni, we produced a panel of monoclonal
antibodies (MAb) to guinea pig leukocytes. These were immunohistochemically classified into 15 types and
included MAb to the major histocompatibility complex (MHC) Class I and Class II molecules, shared antigens of all
lymph node cells or between lymph node cells and Langerhans' cells (LC), T cells and macrophages (M phi), and M
phi including the large Tingible body M phi in the secondary follicle. Varied MAb to M phi, including commercially
available MAb (MR-1), were negative with ATPase- and MHC Class II-positive cells accumulated in the skin
exposed to S. mansoni. Three MAb (HUSM-30 and 46, and commercially available MSgp2) detected an identical
staining profile of accumulated cells with epidermal LC, but two MAb (HUSM-12 and 42) positively stained
accumulated cells but not resident LC. These results indicate that the cells accumulated in the guinea pig skin within
a few days after exposure to attenuated cercariae of S. mansoni are closest to LC, not to Mo, and may be bloodborne LC/dendritic cells.
Immunology 1995 Feb;84(2):233-40
Role of epidermal Langerhans' cells in the induction of protective immunity to
Schistosoma mansoni in guinea-pigs.
Sato H, Kamiya H.
Department of Parasitology, Hirosaki University School of Medicine, Japan.
Percutaneous exposure of guinea-pigs to attenuated or normal larvae of Schistosoma mansoni induced proliferative
T-cell responses in the skin-draining lymph nodes (SLN). The responses elicited by attenuated larvae were stronger
and more prolonged [2-12 days post-infection (p.i.)] than those by normal larvae (3-8 days p.i.). The former were
coincident with greater and more sustained increases in numbers of SLN dendritic cells. During this event,
epidermal Langerhans' cells (LC) showed marked changes in their distribution and morphology. Resident LC were
similarly exhausted by either attenuated or normal larvae between 12 hr and 1 day p.i., but thereafter more bloodborne LC were recruited around the former, since reaggregation of LC around these persisted larvae was more
frequent and intensive, and enhanced replenishment of epidermal LC was achieved by 8 days p.i. When the skin
depleted of epidermal LC by short-wavelength ultraviolet (UVC) irradiation was exposed to attenuated larvae,
consequent T-cell responses were delayed. Excision of the whole exposed skin on day 4 p.i. also reduced T-cell
responses to marginal levels. These results indicate that during the afferent phase of immunity to S. mansoni,
efficient T-cell responses in the SLN need an active involvement of not only resident LC but also blood-borne LC as
immunostimulatory cells.
J Parasitol 1998 Aug;84(4):764-70
Overproduction of SM28GST in a baculovirus expression vector and its use to
evaluate the in vivo immune responses of mice vaccinated against Schistosoma
mansoni with naked DNA encoding the SM28GST gene.
Kayes SG, Shaneyfelt RC, Monteiro C, O'Brien JJ.
Department of Structural and Cellular Biology, College of Medicine, University of South Alabama, Mobile 366880002, USA.
To evaluate the immune responses of mice vaccinated intramuscularly with naked DNA encoding a single parasitederived gene, sufficient quantities of protein are necessary for use in the immunological assays. A plasmid carrying
the cDNA encoding the entire sequence for the 28-kDa Schistosoma mansoni glutathione S-transferase (Sm28GST)
was used as a source of naked DNA to vaccinate mice. Using polymerase chain reaction employing custom primers
to add Eco RI and Hind III restriction sites at the 5' and 3' ends, respectively, a 651-bp fragment was amplified from
the vaccine plasmid. This product was isolated, ligated into the pFastBac HTb donor plasmid containing a 6X
histidine (6X-his) tag, and transposed into the baculovirus expression vector system. Following blue white selection
screening, high molecular weight DNA was isolated and transfected in Sf21 insect ovary cells using a liposomal
preparation. Culture medium containing infective virus particles was used to infect a series of Sf21 cultures and the
cells were lysed after 3-5 days. The lysates were subjected to immobilized metal (Ni-NTA) affinity chromatography
from which the 6X-his-tagged recombinant Sm28GST was eluted in 250 mM imidazole. The eluted protein was
probed with a polyclonal rabbit antibody specific for the Sm28GST and subsequently recognized using a
monoclonal antibody specific for the 6X-his tag following concentration of the pooled fractions. Mice were
vaccinated intramuscularly with purified plasmid DNA encoding either the Sm28GST or firefly luciferase. Skin tests
performed using recombinant Sm28GST were positive in only those mice vaccinated with naked DNA encoding the
Sm28GST gene. In a different group of experimental mice, only sera from mice vaccinated with naked DNA
encoding Sm28GST contained IgG-specific anti-Sm28GST antibodies at 14 days postvaccination, and at 42 days the
levels were suggestive of an anamnestic response. These results suggest that naked DNA vaccination of mice is
capable of inducing both antigen-specific cell-mediated and humoral immune responses against Sm28GST and
further strengthen the case for this antigen being a vaccine candidate.
Mol Biochem Parasitol 1998 Oct 30;96(1-2):15-25
Characterization of Sm20.8, a member of a family of schistosome tegumental
antigens.
Mohamed MM, Shalaby KA, LoVerde PT, Karim AM.
Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, Egypt.
Two cDNA clones each encoding a 20.8-kDa protein (Sm20.8) were identified from the human blood fluke
Schistosoma mansoni sporocyst and adult worm cDNA expression libraries by antibodies derived from rabbits
vaccinated with irradiated cercariae and purified over an NP-40 extract of 3h schistosomula. Each identified cDNA
has an open reading frame encoding a protein of 181 amino acids and shows homology (29-30%) with Sm21.7,
Sm22.6, and Sj22.6, previously identified as belonging to a family of soluble schistosome tegumental antigens. An
EF-hand calcium-binding motif is found in Sm20.8 protein in two different positions. However, neither motif binds
45calcium (45Ca) Recombinant Sm20.8 showed immunoreactivity with sera from infected humans and rabbits
vaccinated with irradiated cercariae. Polyclonal rabbit sera against the Sm20.8 recognized the native protein in an
extract of infected snail (sporocyst), cercariae, 3 hour schistosomules (3 h NP-40) and an adult worm preparation but
not in uninfected snail tissue or eggs. Further demonstration that Sm20.8 was expressed in the different
developmental stages of the parasite was by RT-PCR. Confocal microscopy demonstrates that Sm20.8 localizes to
the tegument of adult worms and 3 h np-40. The IgG fraction specific to Sm20.8 mediated complement killing of
schistosomules in vitro by 34%. Vaccination of mice with naked DNA containing the Sm20.8 gene and
subsequently challenged with cercariae showed 30% reduction in worm burden compared to controls.
Vaccine 1999 Mar 17;17(11-12):1338-54
Recombinant vaccinia viruses and gene gun vectors expressing the large
subunit of Schistosoma mansoni calpain used in a murine immunizationchallenge model.
Hota-Mitchell S, Clarke MW, Podesta RB, Dekaban GA.
The John P. Robarts Research Institute, Department of Microbiology and Immunology, University of Western
Ontario, London, Canada.
Schistosomiasis is a parasitic disease affecting over 200 million people every year in tropical regions of the world.
Drug treatment and other existing control measures are costly and have failed to eliminate the incidence of infection,
morbidity and mortality due to Schistosoma mansoni infection. Vaccination of susceptible individuals using
recombinant vaccines encoding key S. mansoni antigens may be the most effective and least expensive means of
controlling schistosomiasis. A candidate vaccine antigen is p80, the large subunit of the S. mansoni protease,
calpain. In our vaccine studies, we have employed both the wild-type p80 and a mutant p80 (mut p80) in which an
active site amino acid was genetically altered to create a less proteolytically-active enzyme. Two vaccine delivery
approaches were implemented using p80 or mut p80 as vaccine antigen: recombinant vaccinia virus (RVV)
inoculation and DNA immunization via the Accell gene gun (GG) delivery system. RVV's expressing p80 and mut
p80 were generated and tested for recombinant protein expression in vitro. These RVV's were tested for protective
capacity in mouse challenge studies. Neither subcutaneous nor intranasal vaccinations with RVV-p80 or RVV-mut
p80 were capable of significantly reducing the mean worm burdens of vaccinated mice. A GG-RVV combination
immunization regime using WRG-vectors encoding p80 and mut p80 for GG priming and the RVV's for boosting
prior to S. mansoni challenge infection was performed and no significant protection was obtained over two repeated
studies. However, duplicate challenge studies involving GG immunization of mice with WRG-vectors encoding p80
or mut p80 revealed that 3 inoculations of mice with WRG-full5' mut p80 (containing the full 5' untranslated region
of mut p80) provided 60% protection which was statistically significant (p < 0.05). These preliminary in vivo
studies demonstrate the potential for further study of the protection afforded by gene gun-delivered WRG-full5' mut
p80 into subsequently-challenged mice. Such studies may pave the way to effective vaccination of humans using
WRG DNA vectors expressing a schistosomal calcium-activated neutral protease.
J Infect Dis 1999 Aug;180(2):454-63
Control of schistosomiasis pathology by combination of Sm28GST DNA
immunization and praziquantel treatment.
Dupre, Herv M, Schacht AM, Capron A, Riveau G.
Telethon Institute for Gene Therapy, Science Park DIBIT-HSR, 20132 Milan, Italy.
Today the control of schistosomiasis infection relies only on the use of praziquantel (PZQ) chemotherapy. However,
PZQ treatment cannot prevent reinfection and progressive development of the pathology. We assessed in a mouse
model the efficiency of a combined therapy, based on the combination of PZQ chemotherapy with Schistosoma
mansoni 28-kDa glutathion S-transferase (Sm28GST) DNA vaccination, designed to limit the pathology. Following
this combined therapy, the long-term survival of the mice was significantly enhanced in comparison with the
survival of mice either vaccinated only or treated with PZQ only. In addition, the development of the pathology
observed in the control groups was almost completely prevented in the vaccinated-PZQ-treated mice and was
associated with a dramatic reduction of egg deposition in the tissues. We showed that PZQ treatment induced the
unmasking of the native GST enzyme at the surface of the worms, thus permitting its neutralization by the
antibodies raised by DNA immunization. This study provides insights into the synergistic mechanisms involved in
an immunointervention strategy associated with chemotherapy for the control of a chronic infection and its
associated pathology.
Vaccine 2000 Apr 14;18(20):2102-9
Immunogenicity of plasmid DNA encoding the 62 kDa fragment of
Schistosoma japonicum myosin.
Zhang YY, Taylor MG, Gregoriadis G, McCrossan MV, Bickle QD.
Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical
Medicine, Keppel Street, London, UK.
The recombinant Schistosoma mansoni 62 kDa myosin fragment, rIrV-5, is highly protective in experimental
animals, however, vaccination of mice and rats with the recombinant Schistosoma japonicum homologue, rSj62, did
not induce significant resistance against S. japonicum infection. To explore alternative ways of presenting this
antigen, we further constructed a plasmid (VRSj62) which encodes Sj62 using the VR1020 vector and tested it in
vaccination experiments. Four immunisations with 10 microg VRSj62 DNA alone were sufficient to induce high
and progressively increasing levels of IgG antibodies against rSj62 with increasing numbers of injections in CBA/Ca
mice (IgG titre > or =1:25000), and three injections with 50 microg VRSj62 DNA alone induced significant IgG
responses in C57Bl/6 mice (IgG titre, 1:1600). However, vaccination with plasmid DNA entrapped in cationic
liposomes or together with pUC19 DNA as a source of CpG motifs, both of which have been reported to enhance
immune responses, did not enhance specific antibody production. In spite of the stimulation of specific antibodies
against rSj62 with the naked DNA construct no resistance to challenge was demonstrated.
Vaccine 2001 May 14;19(25-26):3606
Immunostimulatory effect of IL-18-encoding plasmid in DNA vaccination
against murine Schistosoma mansoni infection.
Dupre L, Kremer L, Wolowczuk I, Riveau G, Capron A, Locht C.
Laboratoire des Relations Hotes-Parasite et Strategies Vaccinales, INSERM U 167, Institut Pasteur de Lille, F59019 Cedex, Lille, France.
In vivo delivery of DNA encoding antigens is a simple tool to induce immune responses against pathogens. This
approach to vaccination also offers the possibility to codeliver plasmids encoding immunomodulatory molecules in
order to drive immune responses towards optimal protective effects. In the murine model of Schistosoma mansoni
infection, vaccination inducing a Th1 profile has been shown to be protective. In this study, we used a plasmid
encoding the Th1-promoting cytokine IL-18, since we observed that percutaneous infection of Balb/c mice strongly
induced the production of IL-18 mRNA in the skin. Intradermal injection of the IL-18-encoding plasmid prior to
infection did not interfere with parasite migration through the skin although it led to a local and transient cellular
infiltration. When the IL-18-encoding plasmid was codelivered with a S. mansoni glutathione S-transferase
(Sm28GST)-encoding plasmid, a 30-fold increase of antigen-specific IFN-gamma secretion by spleen cells was
observed in comparison to spleen cells from mice that had received only the Sm28GST-encoding plasmid. This
immunostimulatory effect was related to a significant protective effect (28% reduction in egg laying and 23%
reduction in worm burden) which was attributed to a cooperative effect between both plasmids. Therefore, this study
shows that codelivery of an IL-18-encoding plasmid with an antigen-encoding plasmid can stimulate specific
cellular responses and induce protective effects against S. mansoni infection.
Vaccine 2001 Nov 12;20(3-4):359-69
Immunization with plasmid DNA encoding the integral membrane protein,
Sm23, elicits a protective immune response against schistosome infection in
mice.
Da'dara AA, Skelly PJ, Wang MM, Harn DA.
Department of Immunology and Infectious Diseases, Harvard School of Public Health, 665 Huntington Avenue,
Boston, MA 02115, USA.
Schistosomes are helminth parasites infecting at least 200 million people worldwide. In this study, we evaluated the
feasibility of using a nucleic acid vaccine to induce protective immune responses to the Schistosoma mansoni
integral membrane protein Sm23. C57BL/6 mice were immunized by intramuscular injection in three separate
vaccination trials. ELISA and Western Blot analyses indicated that mice immunized with a DNA plasmid construct
encoding Sm23 (Sm23-pcDNA) generated specific IgG for Sm23, while sera from mice immunized with the control
pcDNA plasmid did not. The vaccine elicited IgG(2a), and IgG(1) antibody isotypes. We also tested the adjuvant
activity of IL-12 and IL-4 on humoral responses to Sm23. Co-immunization with plasmid encoding IL-12 did not
affect the level of anti-Sm23 IgG(2a), but did reduce the IgG(1) level. In contrast, co-injection with a plasmid
encoding IL-4 significantly reduced the level of anti-Sm23 IgG(2a), while the level of IgG(1) was largely
unchanged. Importantly, the Sm23-pcDNA vaccine provided statistically significant levels of protection against
challenge infection (21-44%, P<0.001-0.02). Co-administration of plasmids encoding either IL-12 or IL-4 did not
significantly enhance this protective effect.
Vaccine 2001 Nov 12;20(3-4):439-47
DNA vaccination with asparaginyl endopeptidase (Sm32) from the parasite
Schistosoma mansoni: anti-fecundity effect induced in mice.
Chlichlia K, Bahgat M, Ruppel A, Schirrmacher V.
Department of Tropical Hygiene, University of Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
[email protected]
DNA-based vaccine technology was used to induce an immune response in mice against a schistosome cysteine
proteinase, asparaginyl endopeptidase (Sm32). The cDNA coding for Sm32 was cloned in a mammalian expression
vector under control of the CMV promoter/enhancer and expressed for the first time in transfected mammalian cells
as well as in mice immunized with the Sm32-encoding DNA construct. These mice developed antibodies which
recognized the native protein not only in homogenates of Schistosoma mansoni worms but also in the gut on
cryostat sections of the parasites. This DNA vaccine led to an anti-fecundity effect: female worms of a challenge
infection produced 37% less eggs than those growing in naive mice. The results suggest that Sm32 may be a
candidate antigen for the generation of an anti-pathology vaccine against schistosomes.
Int J Med Microbiol 2002 Feb;291(6-7):577-82
Delivery of protein antigens and DNA by attenuated intracellular bacteria.
Gentschev I, Dietrich G, Spreng S, Pilgrim S, Stritzker J, Kolb-Maurer A, Goebel W.
Department of Microbiology, University of Wuerzburg, Germany. [email protected]
On the basis of attenuated intracellular bacteria, we have developed two delivery systems for either heterologous
proteins or DNA vaccine vectors. The first system utilizes attenuated strains of Gram-negative bacteria which are
engineered to secrete heterologous antigens via the alpha-hemolysin secretion system (type I) of Escherichia coli.
The second system is based on attenuated suicide strains of Listeria monocytogenes, which are used for the direct
delivery of eukaryotic antigen expression vectors into professional antigen-presenting cells (APC) like macrophages
and dendritic cells in vitro and can be also used in animal models.
J Med Virol 2002 Mar;66(3):320-8
Co-delivery of GM-CSF gene enhances the immune responses of hepatitis C
viral core protein-expressing DNA vaccine: Role of dendritic cells.
Ou-Yang P, Hwang LH, Tao MH, Chiang BL, Chen DS.
Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, Taiwan.
Hepatitis C virus (HCV) infection has become a critical public health problem worldwide. In Taiwan, it has been
estimated that more than 300,000 people, 2% of the general population, have HCV infection. It has been well
documented that direct delivery of gene intramuscularly can generate both humoral and cellular immunity, which
more closely simulates the conditions of infection. In this study, female Balb/c mice immunized with HCV core
plasmid DNA with or without adjuvant GM-CSF cytokine gene could induce both cellular immune response and
HCV core-specific antibody titers after injection. Furthermore, the mice immunized with HCV core plus GM-CSF
genes showed higher antibody titer and cytotoxic T cell activity compared to those of mice immunized with HCV
core gene only (P < 0.05). To explore the effect of GM-CSF gene, the mice were immunized with reporter gene and
cytokine gene plasmid. Increased levels of reporter protein and infiltrating cells around muscle tissue were noted.
Moreover, the protein could be detected in inguinal node 24 hr after injection, especially in mice immunized with
HCV/core plasmid plus GM-CSF gene. It was also observed that reporter protein expressing CD11c(+) dendritic
cells could be seen in the inguinal node. These data suggest that the GM-CSF gene did enhance HCV core specific
immune response when co-immunized with HCV core DNA plasmid. Although more studies are needed, dendritic
cells that appeared around the naked DNA injection area and that local lymph nodes might play a critical role in the
immune response induced by naked DNA immunization. Copyright 2002 Wiley-Liss, Inc.
: Immunol Lett 2002 Feb 1;80(2):89-96
Oral DNA vaccination: antigen uptake and presentation by dendritic cells
elicits protective immunity.
Cochlovius B, Stassar MJ, Schreurs MW, Benner A, Adema GJ.
Division of Diagnostics and Experimental Therapy, German Cancer Research Centre (DKFZ), Im Neuenheimer
Feld 280, 69120, Heidelberg, Germany
Melanoma differentiation antigens, such as glycoprotein 100 (gp100), have been shown to induce both cellular and
humoral immune responses against melanoma in mouse and man. They are therefore considered as potential targets
for melanoma immunotherapy. In this study, we have used the attenuated auxotrophic mutant strain SL7207 of
Salmonella typhimurium as vehicle for a human gp100 (hgp100) DNA vaccine against melanoma. In vitro studies
indicate that Salmonella/pCMV-hgp100 is efficiently scavenged by dendritic cells, resulting in the expression of the
hgp100 transcription unit in the DC. In addition, oral administration of Salmonella/pCMV-hgp100 results in the
expression of hgp100 RNA and protein by cells exhibiting DC-morphology in mesenteric lymph nodes as soon as 3
days after vaccination. Analysis of the efficacy of the Salmonella/pCMV-hgp100 vaccine in the B16/hgp100 model
demonstrated the induction of strong anti-hgp100 CTL responses and protective immunity in 70% of the vaccinated
mice, but not in control mice. Based on these data, we consider S. typhimurium as a useful vehicle for the design of
recombinant DNA based anti-cancer vaccines.
Dev Biol (Basel) 2000;104:159-64
The cellular basis of immune induction at mucosal surfaces by DNA
vaccination.
Barnfield C, Brew R, Tilling R, Rae A, Wheeler C, Klavinskis LS.
Peter Gorer Department of Immunobiology, Guy's Hospital, GKT, London, UK.
The nasal mucosa provides a simple, non-invasive route to deliver DNA encoding the gene of interest to stimulate
mucosal and systemic immune responses. However, unlike the intradermal or intramuscular routes for plasmid DNA
(pDNA) delivery, immune responsiveness to antigen exposure at the respiratory mucosa is tightly regulated,
consistent with the balance between active immunity and non-responsiveness to pathogenic or inert environmental
antigens. We have characterised the antigen presenting cell types, their distribution and activation status following
nasal vaccination with pDNA-cytofectin complexes encoding model antigens. We demonstrate that nasal
immunisation is associated with expression of the encoded protein in a small population of dendritic cells and
macrophages at the site of pDNA delivery, in the draining lymph nodes (LN) and in the spleen. Antigen expression
by nasal dendritic cells was associated with up-regulation of surface MHC class II and CD86 expression and
functional activation of T-lymphocytes. The results highlight the potential of intranasal vaccination with pDNA,
provided the activation / costimulatory requirements for an active immune response are achieved.
Immunol Lett 2001 Sep 3;78(2):103-11
Dendritic cell discoveries provide new insight into the cellular immunobiology
of DNA vaccines.
Coombes BK, Mahony JB.
Department of Medical Sciences, Father Sean O'Sullivan Research Centre, St. Joseph's Hospital, McMaster
University, 50 Charlton Avenue East, Hamilton, Ontario, Canada L8N 4A6. [email protected]
The evolution of increasingly virulent human pathogens, together with the rapid onset of antimicrobial resistance
has created a need for new vaccination strategies. Nucleic acid vaccines, based on recombinant DNA technology are
a promising new vaccine formulation capable of eliciting both humoral and cellular immune responses. This
technology has been experimentally validated in animal models of pathogen challenge and tumor protection
following administration of a DNA vaccine and has led to extensive research into the mechanisms of protective
immunity. We focus here on the cellular and molecular mechanisms leading to cell-mediated immune responses to
DNA vaccines and discuss these mechanisms in light of recent advances in the field of dendritic cell
immunobiology. In particular, the potential involvement of: (i) the CpG pattern-recognition receptor, toll-like
receptor-9; (ii) the dendritic cell-specific surface adhesion molecule, DC-SIGN; and (iii) the molecular interactions
between CD40 and CD154 in the evolution of protective cell-mediated immunity to DNA vaccines are discussed.
An improved understanding of the precise mechanisms leading to protective cellular immunity following DNA
vaccination may help in the design of novel DNA constructs containing immunostimulatory features that target one
or more of these mechanisms, with the aim of increasing the immunogenic potential and protective efficacy of DNA
vaccines.