Download Adverse Effects

IV. Immunosuppressive antibodies
-
The use of antibodies plays a central role in prolonging
allograft survival. Most of them block T cell surface
molecules involved in signaling immunoglobulins. They
include:
◦ Antithymocyte globulins (ATG).
◦ Muromonab-CD3
◦ Rho (D) immunoglobulin.
◦ Basiliximab
◦ Daclizumab
◦ Infliximab
Immunosuppressive antibodies (cont’d)
Preparation:
1. By immunization of either rabbits or horses with human
lymphoid cells producing a mixture of polyclonal
antibodies directed against a number of lymphocyte
antigens (variable, less specific).
2. Hybridoma technology: produce antigen-specific,
monoclonal antibody (homogenous, specific).
 Hybridomas are produced by fusing mouse antibodyproducing cells with human immortal, malignant bone
marrow cells. Hybrid cells are selected and cloned, and the
antibody specificity of the clones is determined. Clones of
interest can be cultured in large quantities to produce
clinically useful amounts of the desired antibody.
Hybridoma technology
Preparation of immunosuppressive antibodies (cont’d)
3. Recombinant DNA technology:
• Antibodies can be obtained by replace part of the mouse
gene sequence with human genetic material thus
humanized antibody produced (less antigenicity-longer
half life).
• The names of monoclonal antibodies conventionally
contain “Muro-” in their names are from a murine
(mouse) source or contain “zu” or “xi” if they are
humanized .
1-Antithymocyte globulins (ATG)




Thymocytes are cells that develop in the thymus and serve
as T-cell precursors.
The antibodies developed against them are prepared by
immunization of large rabbits or horses with human
lymphocytes (Polyclonal antibodies).
The antibodies bind to the surface of circulating T lymphocytes,
which then undergo various reactions, such as antibodydependent cytotoxicity, and apoptosis.
The antibody-bound cells are phagocytosed in the liver and
spleen, resulting in lymphopenia and impaired T-cell responses
& cell-mediated immunity.
CD3
CD3
CD3
Antithymocyte globulins (cont’d)
Pharmacokinetics:


The antibodies are slowly infused I.V.
Their half-life extends from 3 to 9 days.
Therapeutic uses:



They are primarily employed, together with other
immunosuppressive agents (like cyclosporine), at the time of
transplantation to prevent early or acute allograft rejection,
or they may be used to treat severe rejection episodes .
Corticosteroid-resistant
Acute allograf rejection.
Adverse effects:



Hypersenstivity (chills and fever, skin rashes)
leukopenia and thrombocytopenia,
Tendency to infections especially CMV or other viruses.
2- Muromonab-CD3



Muromonab-CD3 is a murine monoclonal antibody that
is synthesized by hybridoma technology and directed
against cell surface glycoprotein CD3 antigen of human T
cells.
Binding to CD3 (antigen recognition site) leading to
disruption of T-lymphocyte function, and depletion of.
circulating T cells with decreased immune response.
Because muromonab-CD3 recognizes only one antigenic
site, the immunosuppression is less broad than that seen
with the polyclonal antibodies. T cells usually return to
normal within 48 hours of discontinuation of therapy.
Muromonab-CD3 (cont’d)
Pharmacokinetics:



The antibody is administered by I.V., initial binding of muromonabCD3 to the antigen transiently activates the T cell and results in
cytokine release (cytokine storm)
It is therefore usual to premedicate the patient with Prednisolone,
diphenhydramine , and acetaminophen to alleviate the cytokine
release syndrome.
The antibody is metabolized by liver enzymes and excreted in the bile.
Therapeutic uses:



Muromonab-CD3 is used for treatment of acute rejection of renal
allografts
For treatment of corticosteroid-resistant allograft rejection in cardiac
and hepatic transplant patients.
It is also used to deplete T cells from donor bone marrow prior to
transplantation.
Muromonab-CD3 (cont’d)
Adverse effects:
• Anaphylactic reactions may occur.
• Cytokine release syndrome may follow the first dose. The
symptoms can range from a mild, flu-like illness and fever,
muscular and joint pain, pulmonary edema and acute
respiratory distress and rarely some thromboembolic
problems, in addition to a life-threatening, shock-like
reaction.
• Central nervous system effects (headache, encephalopathy,
cerebral edema, aseptic meningitis, and seizures) may occur.
• Liability to infections can increase,
• Muromonab-CD3 is contraindicated in patients with a
history of seizures, in those with uncompensated heart
failure, in pregnant women, and in those who are breastfeeding.
3- Rho (D) / Rh0(D) immune globulin



Rho (D) is a concentrated solution of human IgG containing higher titer
of antibodies against Rho (D) antigen of red cells.
In a Rh negative mother Rho(D) Immune Globulin, can take out any
fetal RhD-positive erythrocytes which have entered the maternal
systemic circulation from fetal circulation before sensitization of the
maternal immune system to react to fetal Rh D antigens, which can
cause rhesus disease in the current or in subsequent pregnancies.
Given to Rh-negative mother within 24-72 hours postpartum (either
natural delivery or c- section) and after miscarriage or therapeutic
abortion of Rh-positive baby (2 ml, I.M.) to prevent development of
an immunological condition known as Rhesus (Rh) disease of the
subsequent Rh positive pregnancy. The disease ranges from mild to
severe. In mild cases, the fetus may have mild anaemia with
reticulocytosis. In moderate or severe cases the fetus may have a more
marked anaemia and erythroblastosis fetalis (hemolytic disease of the
newborn). When the disease is very severe it may cause hydrops fetalis
or stillbirth.


Treatment of mother may happen during pregnancy if a
sensitizing events during pregnancy occures like
amniocentesis, ectopic pregnancy, abdominal trauma and
external cephalic version. The anti-RhD)antibodies
preparation has an FDA Pregnancy Category C. In many
countries it is given by I.M. injection as part of modern
routine antenatal care at about 28 weeks of pregnancy.
This is considered a type of passive immunity and its effect
will wear off after about 4 to 8 weeks as the anti-Rh
antibodies gradually decline to zero in the maternal blood.
Adverse Effects:
◦ Local pain
◦ Fever




A humanized monoclonal antibody directed against surface
protein (CD52) – expressed on lymphocytes, monocytes,
macrophages, natural killer cells and thymocytes
It exerts its effects by causing profound depletion of T cells
from the peripheral circulation as well as peripheral lymph
nodes.
it is being utilized in combination with low-dose CNIs or
sirolimus especially, in corticosteroid avoidance protocols in
renal and liver transplantation especially in HCV-infected
subjects.
Adverse effects: include Cytokine storm syndrome, requiring
premedication with acetaminophen, and diphenhydramine, in
addition to neutropenia, and anemia.
5- IL-2-receptor antagonists




The antigenicity and short serum half-life of the murine
monoclonal antibody have been averted by replacing most
of the murine amino acid sequences with human ones by
genetic engineering.
Basiliximab is a chimeric human-mouse monoclonal IgG
(25% murine, 75% human protein).
Daclizumab is a humanized monoclonal IgG (90% human
protein).
They have less antigenicity & longer half lives than murine
antibodies
Mechanism of action:



Both compounds are anti-CD25 antibodies and
bind to CD25 (α-subunit chain of IL-2 receptor
on activated lymphocytes)
They thus block IL-2 stimulated T cells
proliferation and & T-cell response to any
antigenic stimulus
interfere with the
proliferation of these cells.
Basiliximab is more potent than daclizumab as a blocker of IL-2
stimulated T-cell replication.
Therapeutic uses:


Both agents have been used for prophylaxis of acute rejection in
renal transplantation in combination with with low-dose CNIs and
corticosteroids.
They are not used for the treatment of ongoing rejection.
IL-2-receptor antagonists (cont’d)
Pharmacokinetics:



Both antibodies are given intravenously.
The serum half-life of Daclizumab is about 20 days, Five doses of
daclizumab are usually administered (the first at 24 hours before
transplantation, and the next four doses at 14-day intervals).
The serum half-life of Basiliximab is about 7 days. Usually, two
doses of this drug are administered (the first at 2 hours prior to
transplantation, and the second at 4 days after the surgery).
Adverse effects:
Both Daclizumab and Basiliximab are well tolerated. Their major
toxicity is GI upset, mild hypersensitivity symptoms with minimal
risk
of
opportunistic
infections
and
post-transplant
lymphoproliferative disorder.
.




TNF-α is proinflammatory cytokine, many chimeric human-mouse
monoclonal IgGs such as infliximab, adalimumab, certolizumab
pegol, and golimumab that were prepared against TNF-α to inhibit
its activity were approved for clinical use.
Etanercept , is a humanized fusion protein produced by
recombinant DNA linking the solubleTNF receptor to the Fc end of
the IgG1 antibody, mimics inhibitory effects of naturally occurring
soluble TNF receptor (TNF- R2).
Mainly used in treatment of autoimmune disorders like rheumatoid
arthritis, psoriatic arthritis, and ankylosing spondylitis.
Adverse effects:
- Infusion reaction – fever, urticaria, hypotension, dyspnoea
- Opportunistic infections – TB, RTI, UTI
V- Interferones





Interferons are a family of naturally occurring, inducible
glycoprotein cytokines that are used clincally in many
purposes. They have different immunomodulating actions.
The interferons are synthesized by recombinant DNA
technology.
Three types of interferon exist, α , β, and γ.
IFN- γ : Acts as immunostimulant. It increases expression of
MHC molecules, enhances the activity of macrophages and
natural killer cell, and stimulates production of IgG.
IFN- α, β : Act as inhibitors of cellular proliferation (cancer
cells, Immune cells and viral infections)
Interferones (cont’d)
Therapeutic uses:
◦ Treatment of certain infections e.g. Hepatitis B&C
(IFN- α ).
◦ Certain forms of cancer e.g. melanoma, renal cell
carcinoma (IFN- α ).
◦ Autoimmune diseases e.g. Rheumatoid arthritis (IFNα & β ).
◦ Multiple sclerosis (IFN- β): reduced rate of
exacerbation.
Adverse effects:
Fever, chills, myelosuppression.
Immunostimulants
Immunostimulants




Immunosstimulants are substances that
stimulate the immune system by inducing
activation or enhancing the activity of any of its
components.
Immunosstimulant agents are now utilized to
enhancing cellular and/or humoral immunity
should benefit people with immune deficiencies
(primary and secondary) and severe infections
and cancers.
Degree of stimulation relatively small





1- Synthetic drugs:
e.g. Levamisole and Thalidomide
2- Immunostimulant vaccines:
e.g. BCG vaccine
3- Recombinant cytokines :
e.g. IFN-,GM-CSF, IL-2
4- Immunization vaccines (active and passive)
5-Immunostimulatory MAbs
1- Levamisole
Livamisole (Ergamisol, Vapal, Katrex)
•
•
Levamisole (LMS) is an imidazothiazole derivative that has an
immunomostimulator and anthelminthic activities .It is
usually used as phosphates or hydrochloride salts.
It has been used in humans to treat many parasitic worm
infections, In addition to its utilization as immunostimulant in
combination with some chemotherapeutic agents (like 5-FU)
to treat many types of human cancers like colon cancer,
melanoma, and head and neck cancer.




Levamisole’s mechanism of action for its immunostimulating effects
are not well understood. It is believed it enhances cell-mediated
immune function in peripheral T- and B-lymphocytes and
stimulates phagocytosis by monocytes. Its immune stimulating
effects appear to be more pronounced in the immunecompromised individuals.
Levamisole may also interferes with the growth of cancer cells and
slows their growth and spread in the body by blocking carbohydrate
metabolism.
Side effects include GI upset, loss of appetite, change in taste and
smell, muscle aches, fatigue, dizziness, headache and skin rash.
Alcohol and alcohol containing products should be avoided while
taking levamisole. Flushing, nausea, vomiting, stomach pain
headache, swelling, and rashes can occur.
Thalidomide


Thalidomide was first introduced as a sedative and antiemetic
drug during the period of world war II, it was withdrawn due
to sever side effects “teratogenicity and neuropathy”.
Now there are revived interests in using thalidomide as
immunostimulating agent used to treat a number of medical
conditions like cancer (e.g. multiple myeloma) and tough
infectious diseases like leprosy.


Thalidomide has many mechanisms by which it exerts the
immunostimulatory effect:
- It stimulates T-cells proliferation
- It enhances activation of NK cells
- It stimulate production of IL-2& IFN-γ and inhibits the
production of other cytokines (e.g. IL-10 ).
- Thalidomide has antiangiogenic effect (inhibits the growth of
new blood vessels), which makes it be useful in treating some
types of cancer like multiple myloma, prostate cancer and
lymphomas.
Thalidomide is contraindicated in women within childbearing
potential due to the high risk of teratogenicity.
Bacillus Calmette-Guérin (BCG) vaccine



BCG is a vaccine prepared from life-attenuated bovine
tuberculosis bacillus, Mycobacterium bovis, that has lost its
virulence in humans, but still retained its strong antigenicity
enough to stimulate immune system to produce the
corresponding antibodies.
BCG is used predominantly as upperarm I.D. injection for
vaccination against tuberculosis.
BCG is also used as intravisceral therapy in the treatment of
superficial forms of bladder cancer and colorectal cancer. The
mechanism is unclear, it appears a local immune reaction is
mounted against the tumor (may act in part by stimulating
TNF-α release from macrophages).


A number of cancer vaccines in development use BCG as
an adjuvant to provide an initial stimulation of the
patients' immune system.
The most noticeable adverse effects associated with BCG
are causes some pain and scarring at the site of injection,
hypersensitivity, chills, fever, skin rashes, hypotension
and may be shocking.

Human cytokines prepared by recombinant DNA
technology
1- human recombinant IL-2 (rhIL-2 );
aldesleukin, proleukin



It binds to the IL-2 receptor on T-lymphocytes
It stimulates the proliferation and diffrentiation of
antigen-primed (helper) T cells, which subsequently
produce more cytokines( IL-2,IL-1, IFNɣ, and TNFα).
These cytokines collectively activate natural killer cells,
macrophages, and cytotoxic T lymphocytes.


rhIL-2 is used in metastatic renal cell cancer and
melanoma.
Adverse effects:
• Inflammation and increased vascular permeability,
peripheral edema, fever and hypotension.
• Cardiac arrhythmia, anemia, nausea, vomiting,
diarrhea, confusion





INF-ɣ boosts the activity of macrophages and NK cells.
It stimulates the expression of MHC molecules and production
of IgG.
It causes cancer cells to produce more antigens , suppresses the
growth of cancer cells and inhibits angiogenesis
It is approved for use with leukemia, lymphoma, renal cancer
and melanoma in addition to prevention of secondary
infections in chronic granulomatous diseases.
Adverse effects:
• Flu-like symptoms – fever, chills, headache, GI disturbance
• Hypotension, Arrhythmia
• CNS- depression and confusion



GM-CSF is a cytokine secreted mainly by macrophages,
mast cell in addition to endothelial cells, and fibroblasts. It
functions as a white blood cell growth factor.
rhGM-CSF interacts with specific cell-surface receptors
found on various immune component cells. GM-CSF
stimulates stem cells to produce granulocytes (neutrophils,
eosinophils, and basophils) and monocytes. It also activates
the phagocytic activity of mature monocytes and prolongs
their survival in the circulation.
GM-CSF is used in cancer patients after chemotherapy to
treat neutropenia and increased risk of serious infection
after receiving cancer chemotherapy


It is also used to accelerate myeloid recovery after
autologous BMT in patients with lymphoma, and acute
lymphoblastic leukemia
Adverse effects: include fever, malaise, arthralgias,
myalgias, and a capillary leak syndrome characterized by
peripheral edema and pleural or pericardial effusions.
Allergic reactions may occur but are infrequent.
Spleenomegaly is a rare but serious complication of the
use of GM-CSF.



vaccines are biological preparations that improves immunity. It
could act against particular disease or boost the general immune
function.
Active immunization (vaccination): include administration of the
antigen of the disease-causing microorganism in the form of
weakened or killed microbe , its toxins or a specific protein or
peptide constituent of an organism that stimulate the immune
system to recognize these antigens and generate an adaptive
immune response by raising the specific antibodies to destroy it,
and "remember" it, so that the immune system can more easily
recognize and destroy any of these microorganisms that it later
encounters. the response takes days/weeks to develop but may be
long lasting even lifelong.
Vaccines can be prophylactic to prevent or ameliorate the effects
of a future infection by pathogen (e.g. polio vaccine, MMR
vaccine)., or therapeutic (e.g. vaccines against cancer)



Passive immunization: fortification of the immune system by
administration of prepared imunglobulines antibodies to protect against
infection; it gives immediate, but short-lived protection for several
weeks to 3 or 4 months at most. It is mainly used as replacement
therapy in individuals with primary immune deficiency diseases . Also, to
manage some acute infections when active vaccination is inadequate
Passive immunity is usually classified as natural or acquired. The
transfer of maternal tetanus antibody (mainly IgG) across the placenta
provides natural passive immunity for the newborn baby for several
weeks/months until such antibody is degraded and lost. In contrast,
acquired passive immunity refers tothe process of obtaining serum
from immune individuals, pooling this, concentrating the
immunoglobulin fraction and then injecting it to protect a susceptible
person.
Examples: vaccines of hepatitis B, botulism, diptheria, tetanus, rabies



Monoclonal antibodies prepared against surface
antigenic marker proteins specific for tumor cells (e.g.
anti-HER2/Neu, anti-VEGF “Avastin”)
mAbs act directely when binding to a cancer specific
antigens and induce immunological response to
cancer cells. Such as inducing cancer cell apoptosis,
inhibiting growth, or interfering with a key function.
mAbs also was modified to deliver a toxin,
radioisotope, cytokine or other active conjugates
into cancer cells.
mAbs treatment for cancer cells
ADEPT, antibody directed enzyme prodrug therapy; ADCC, antibody
dependent cell-mediated cytotoxicity; CDC, complement dependent
cytotoxicity; MAb, monoclonal antibody; scFv, single-chain Fv fragment.