Questions 15-17. Match the immunoglobulin to its main function or characteristic. 11 example of: 15. IgM 16. IgG 17. IgD a found on surface of B cells and act as B cell receptors b. protect against multicellular parasites and involved in allergic reactions c. found in breast milk, saliva, and on mucous membranes secreted as a dimer d. 75% of all immunoglobulins circulating in the blood, secreted as a monomer e large pentamer that is the first responder binding lots of antigen 18. These cells make and secrete antibodies and are made after B cells are activated a. Macrophages b. Cytotoxic T cells c. Natural killer cells d. Helper T cells Plasma cells 19. The CD receptors on T cells serve a very important function. Which of the following best describe the function of these receptors? CD receptors bind... a. directly to endogenous antigen. b. directly to B cell receptors. c. to MHC proteins d. directly to exogenous antigen e. all of these 20. This process is involved in generating roughly 1 x 10 differently shaped receptors of specific or adaptive immunity far more than the total number of genes in the human genome) a. endogenous antigen processing b. exogenous antigen processing c. phagocytosis d. opsonization e. V(D) recombination