Download immune response

IMMUNE RESPONSE
 It includes reactions against any antigen.
 The consequences are usually beneficial or some
times may be injurious to the host.
 The adaptive response can be antibody-mediated
(humoral), cell-mediated (cellular), or both.
Sequence of events occur after entry of a pathogen
ENTRY
APC
Through MHC
LYM
Rec T LC
LYMPHOKINES
Humoral Immune Response
 Helper T lymphocytes (CD4) recognize the pathogen's
antigens complexed with class II MHC proteins on the
surface of an APC and produce cytokines that activate B
cells expressing antibodies that specifically match the
antigen.
 Major host defense functions of antibodies include
neutralization of toxins and viruses and opsonization
(coating) of the pathogen, which aids its uptake by
phagocytic cells.
 It applies mainly to extracellular pathogens and their
toxins.
Primary and secondary immune responses
It is slow, short lived with long lag phase and low
titre persists for short period.
Secondary response is prompt, powerful and
prolonged with short negligible lag phase much
higher levels of antibodies last for long period.
MONOCLONAL ANTIBODIES
Normally antibodies produced by infection or
antigens will have antibodies against multiple
epitopes.
 A single antibody producing cell of clone
produces against a single epitope.
Antibodies produced by a single clone and
directed against a single epitope are called as
monoclonal antibodies
Uses:
1. Diagnostic use
2. Therapeutic use
Factors influencing antibody production
1. Genetic factors
2. Age
3. Nutritional status
4. Route of administration
5. Dose of Antigen
6. Multiple antigens
7. Adjuvants
8. Immunosuppressive agents
9. Effect of antibody
Cellular immune response
Each class of T cells produces cytokines, becomes
activated, and expands by clonal proliferation.
Helper T cell activity, promotes the development
of delayed hypersensitivity and thereby also serves
in the defense against intracellular agents,
including intracellular bacteria (eg, mycobacteria),
fungi, protozoa, and viruses. Cytotoxic T cell
activity is aimed mainly at the destruction of cells
in tissue grafts, tumor cells, or cells infected by
some viruses.
Cytokines
These are biologically active substances
secreted by lymphocytes, monocytes and
others cells.
Selected Important Cytokines.
Name
Major Cellular Source
Selected Biologic Effects
IL-1 (interleukin-1)
Macrophages
Cell activation, fever
IL-2 (interleukin-2)
T cells
T cell growth and activation
IL-3 (interleukin-3)
T cells
Hematopoiesis
IL-4 (interleukin-4)
T cells, mast cells
B cell proliferation and switching to
IgE, TH2 differentiation
IL-5 (interleukin-5)
T cells
Differentiation of eosinophils,
activates B cells
IL-7 (interleukin-7)
Bone marrow stroma
cells
T cell progenitor differentiation
IL-8 (interleukin-8)
Macrophages, T cells
Chemotactic for neutrophils
IL-10 (interleukin-10)
Macrophages, T cells
Inhibits activated macrophages and
dendritic cells
IL-12 (interleukin-12)
Macrophages
Differentiation of T cells, activation
of NK cells
IFN-alpha, beta
Macrophages
fibroblasts
Antiviral, Activates macrophages,
Immunosuppressive agents
These inhibit the immune response.
X- radiation, Radiomimetic drugs, Carticosteroids,
Antimetabolites, Antilymphocytic serum.
Used in situations like transplatation to prevent
graft rejection
Detection of CMI
1. Skin test.
2. Lymphocyte transformation test.
3. Migration inhibition factor.
Transfer factor
It is possible to transfer of CMI in man by injecting
the extract from leucocytes.
It is low MW substance of 2000-4000.
Used in 1. T cell deficiency syndrome.
2. Treatment of disseminated infections.
3. Treatment of some cancers.
THANK YOU