immune responses

PRIMARY &SECONDARY IMMUNE RESPONSE
Dr. Baha, H. AL-Amiedi

Primary Immune Response:
This is the first interaction between the antigen and B-cells ,the B-cells will differentiate and become memory cells for future exposure or become mature plasma cells and produce antibodies .the antibody classes strat with IgM, and described as Antigen specific response . lmmunogen injected intramuscular has greater immune response than an immunogen taken orally . A 25-Year old will have a greater immune response than if it given to child.
Secondary Immune Response:
This is anamestic response . It is also known for response of booster shot , it cause a rapid proliferation and differentiation of B-cells to produce large amount of antibody ( mainly IgG). This response is seen with B-cell and DTH T-Cell. An anemnestic response is faster, more specific and longer lasting than primary immune response.
The antigen type is in these responses is B-dependent-Antigen .The time carve is follow factor influencing Antibody production:
1. Age
2. Nutritional status
3. Route of administration
4. Size and Number of doses
5. Multiple antigens
6. Adjuvant
7. Immunosuppressive agent

Cellular Immune Response: -
The term cell rnediated immunity refers to the specific immune responses that do not involve antibodies, induction of cell mediated immune response (CMI) ,The T-cell recognize Antigen through a surface molecule termed the T-cell receptor (TCR) ,Each T-cell possesses adifferent (TCR) to allow it to recognize a different antigen . specifically sensitizing T-lymphocytes comes against the antigen. When sensitized T-cell comes in contact with antigen determinant (epitopes) after the enzymatically degraded antigen into small peptides (epitopes) which binding to class l or class ll and transport to the cell surface; Class l pathway activated CD 8 (Cytotoxic) T-cell ,While Class ll pathway activated CD4 T-Cell (TH2 &TH1 Cells) by the function of Antigen Presenting Cell (APC) ,so T-cell under goes blast transformation and clonal proliferations selectively in paracortical areas of lymph nodes.
lymphokines: material required as secreted proteins from the activated T-cell , These Lymphokine have several biological function
1-Effect on macrophage : This Lymphokine is function is covered out
by the following:
a-Macrophage inhibition Factor (MIF)
b-Macrophage aggregation Factor (MAF)
c-Macrophage chemotactic Factor (MCF)
2-Effect on Lymphocytes:This role is done by:
a-Blastogenic factor (BF)
b-Potentiation factor (PF)
c-Cell co-operation factor (CE).
3-Effect on granulocyte: •.
a-Inhibition factor (IF)
b-Chemotactic factor(CF)
4-Effect on tissue cultur:
a-Lymphotoxin
b-Proliferation inhibition factor (PIF)
c-Interferon








Imunoglobuline
Or Antibodies
Are glycoprotein present in the gamma- globulin fraction of serum. which make 20- 25 % of serum protein Immunoglobulin generally natural present in blood without previous antigenic stimulation However antibody are produce
specifically by activated B-cell( plasma cell ) after antigenic stimulation . Thus all antibodies are Immunoglobulin while no all Immunoglobulin are antibody
The characteristic of antibody are
1. glycoprotein in nature.
2. specific to antigen induce them.
3. React specifically with their own antigen
Antibody are distributed in serum, body fluid, Urine ,Saliva , Ear wax and tears.
The antibody molecule are found to be of different classes , the classification depend on :
1-The molecular size
2-Natur of carbohydrate,
3-Amino acid sequence.
The classes of Antibodies are IgM, IgG, IgE & IgD.
The difference between these Classes depend on the type of heavy chain in each molecule, Immunoglobulin , the term immunoglobulin is structural & chemical concept while antibody is biological and function concept.
The basic structure of antibody Molecule
antibody are made up of one or more units (monomers) comprising four polypeptides which are:
1- two identical light chain (I.C) consist of 214 amino acid, 106 amino acid respect the constant region of molecule while variable region consist of 108 amino acid for Kappa & Lambda
2- two identical heavy chain (HC) consist of 440 amino acid, residues 322 amino acid occur in constant region (CH). 118 amino acid in the variable region (VH)
There are 5 Classes of (HC) Heavy chain content of five Classes of lmmunoglobulines:
1-(Gamma) or lgG
2-(Mu) or lgM
3-(Alpha) or lgA
4-(Epsilon) or lgE
5-(Dalta) or IgD
The variable region in both heavy chain (HC) and light chain (LC) are consist the antigen combination sit.
Fab : it is amino acid terminal half of heavy chain & light, it act as Antigen binding fragment .
Fc: It is carboxyl terminal half of heavy chain & determine biological properties of Immunoglobulin
These chains are connected to form Y- shaped molecules, IgM is a pentamer of the basic structure ,IgA is usually a dimer , and lgG, IgD & lgE are monomeric