Antigens/Antibodies. Chapters 4-6. Antigen Any substance that can bind to an antibody or T cell receptor. Immunogen Any substance that can elicit an immune response All immunogens are antigens Not all antigens are immunogens, i.e. haptens. Antigen vs. Immunogen. Determined by
Overlapping peptides were generated and injected into mice.
The antibody response to each peptide was measured by ELISA.
Comerford, S.A. et al. J. Virol. 65:4681-4690, 1991
Electrophoretic separation of serum proteins
plot of variability as a function of position along the sequence of the amino acids that make up the heavy chain of Ig molecules.
No J chain
Extra 20 aa in tail
Associated with two additional proteins
involved in signal transduction
Unlike the remainder of the IgA which is made in the plasma cell, the secretory piece is made in epithelial cells and is added to the IgA as it passes into the secretions. The secretory piece helps IgA to be transported across mucosa and also protects it from degradation in the secretions.
After exposure to an antigen, much of the initial antibody response occurs in lymphoid tissues:
Antigen-antibody complexes are held together by non-covalent forces (therefore, antigen binding by antibody is reversible)