This course is part of a series taught by Kevin Ahern at Oregon State University on General Biochemistry. For more information about online courses go to http://ecampus.oregonstate.edu/
for the rest of the courses see http://www.youtube.com/playlist?list=PL347B70A1CC0D91C6
This information is provided for all of you who love learning.
1. The immune system contains the innate immunity system and the adaptive immunity system.
2. The innate system uses a Toll-like receptor that binds to the PAMP lipopolysaccharide structure on the surface of Gram negative bacteria.
3. The adaptive immune system system contains two major groups of lymphocytes (immune system cells), B cells and T cells. B cells are involved in the production of antibodies and T cells are involved in both cellular killing, as well as stimulation of the B cells.
4. Immunoglobulin G (IgG) is one of five major antibody classes made by the B lymphocytes of the humoral immune system (cellular immune system described below). IgG is the most abundant antibody in the blood serum. Others include IgA (in mucus), IgM (early responder), IgD (function uncertain), and IgE (parasite protection).
5. The structure of antibodies has several common features. First, they are composed of two sets of Heavy (H) and light (L) chains arranged in a Y shape. Both the H and L chains have constant and variable regions. The variable regions of the H and L chains are adjacent to each other and the variation in these regions are responsible for antibody diversity (108 different shapes). The different classes of antibodies vary in the H chains in the constant region.
6. Molecules bound by antibodies are called antigens. Specific structural regions of an antigen bound by an antibody are called epitopes.
7. IgM antibodies are the first responders of the humoral immune system.
8. Antibody diversity arises from recombination of DNA sequences and splicing of mRNA sequences for coding for the variable regions of H and L chains.
9. For the light chains, the coding sequences are on human chromosome 2 and involve three protein domains - V, J, and C regions. V is the variable portion, J is the portion that joins the V to the C, which is the constant region. Mixing and matching of domains by recombination generates tremendous diversity - over 1000 antibodies per base pair of the human genome.
10. In H chains (chromosome 14), recombination occurs between segments V,D, J and C. Recombination within the constant regions of the H chains can result in "class switching" in which a desired variable segment is swapped among to the various segments to put the binding site onto regions to make IgG, IgE, etc.
Also check out the free textbook "Biochemistry Free and Easy" at: http://biochem.science.oregonstate.edu