Download Immunology - PharmaEuphoria

ABHISHEK D. CHOUHAN
Immunology and Immune system
IMMUNOLOGY
It is the study of the components and function of the
immune system.
IMMUNE SYSTEM
Molecules, cells, tissues & organs which provide
non-specific and specific protection against.
Microorganisms
Microbial toxins
Tumor cells
Antigens
Some chemical that creates immune response. These
are substances which, when introduced into the
body, stimulate the production of antibodies.
CHEMICAL NATURE
These are mostly the conjugated proteins like
lipoproteins, glycoproteins and nucleoproteins.
Antigens
STRUCTURE
Antigenic determinants or epitopes are components of
antigen. Each antigen carries many epitopes. Each Yshaped antibody molecule has at least two binding sites
that can attach to a specific epitope on an antigen. An
antibody can also bind to identical epitopes of two
different cells at the same time which can cause
neighboring cells to aggregate. Antigens combine with
the antibody. The combination is very much like the
lock and key analogy.
Antigen types
Based upon the ability of antigens to carry out their functions,
antigens are of two types
complete antigens
Incomplete antigens (haptens)
A complete antigen is able to induce antibody formation &
produce a specific and observable reaction with the antibody so
produced.
Haptens are substances which are incapable of inducing
antibody formation by themselves, but can be capable of
inducing antibodies on combining with larger molecules
(normally proteins) which serve as carriers.
Antibodies
Proteins that recognize and bind to a particular
antigen with very high specificity.
It is a protein produced by the body’s immune
system when it detects harmful substances, called
antigens. Ex. of antigens includes microorganisms
(bacteria, fungi, parasites, and viruses) & chemical.
Each type of antibody is unique & defends the body
against one specific type of antigen.
Types of antibodies
1. Immunoglobulin G
2. Immunoglobulin A
3. Immunoglobulin M
4. Immunoglobulin D
5. Immunoglobulin E
Difference between Antigen and
Antibodies
Antigen
Antibodies
Protein or polysaccharide molecule
Protein molecule
Foreign material that stimulates
antibody formation
Synthesized by an animal to combat
foreign material
May occur on the surface of a microbe May occurs on the surface of a plasma
of as a free
cell & also in body
molecule
fluids
Binds to a macrophage to reach a
helper T-cell to initiate
immune response.
Directly joins an antigen to destroy
the latter.
Antigen-Antibodies reactions
1. Agglutination
2. Precipitin
3. Complement fixation
4. Opsonisation
5. Neutrilisation
6. Immune cytolysis
7. Immune adherence
8. Immunofluorescence
9. Radio Immunoassay (RIA)
10. Enzyme Linked Immuno Sorbent Assay (ELISA)
Hypersensitivity reactions
Over reaction of adaptive immune response to
harmless antigens.
Hypersensitivity refers to excessive undesirable
(damaging, discomfort-producing and sometimes
fatal) reactions produced by the normal immune
system. Hypersensitivity reactions require a presensitized (immune) state of the host.
These reactions can be divided into four types,
based on the mechanisms involved & time taken for
the reaction.
Four types of reactions (I-IV)
Type I: Anaphylactic Reactions/Immediate
(typical bee-sting or hay fever allergic responses)
Type II: Cytotoxic Reactions/Antibody-mediated
(as in mismatched ABO transfusion reaction)
Type III: Immune Complex Reactions
(as in rheumatoid arthritis or in "serum sickness")
Type IV: Cell-mediated Reactions
(seen with positive tuberculin (TB)-skin test
reaction)
Autoimmunity
Antibodies may be produced when the immune
system mistakenly considers healthy tissue a
harmful substances. This is called an autoimmune
disorder. Misdirected adaptive immune response.
Results from a loss of self-tolerance.
Three Types (II, III, IV) of reactions.
Autoimmunity is the response of the adaptive immune
system to self-antigens that occurs when mechanisms of
self tolerance fail. Autoimmunity is one cause of
hypersensitivity.
Autoimmunity can occur in the
following conditions
Graves Disease
Rheumatoid Arthritis
Systemic lupus erythematosus (SLE)
Myasthenia Gravis
Insulin-dependant Diabetes: Auto-reactive Tcytotoxic cells destroy pancreatic beta-cells (the
insulin producing cells).
RIA
ANTIBODY
BACTERIA
IMMUNITY
SENSITIVITY
ANTIGEN
REACTIONS
TOXIN
ELISA
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