Question

a. With reference to the concept of 'afinity maturation', briefly explain why IgG and IgA antibodies are generally of higher afinity than IgM antibodies.

b. Despite this, IgM antibodies can be very effective in activating complement and promoting phagocytosis of bacteria. Provide an explanation for this observation.

Answer 1

CONCEPT OF AFFINITY MATURATION:

a.The IgG and IgA antibodies have higher affinity than IgM antibodies. IgG antibodies displace IgM antibodies for antigens. This typically makes IgM levels to measure. The IgG antibodies with high affinity are removed to avoid negative results. These three antibodies have competitive advantage which varies from antigen to antibody pair to another.

b. IgM antibodies have more antigen binding sites. They can bind 2 antigens by single molecule. It increases the mechanism in phagocytosis bacteria. They neutralize toxins in bacteria. They are attracted to pathogen and activate the complement system.