Polysaccharide antigen with multiple repeating subunits B-cell receptors YY} FIGURE 15.16 T-Independent Antigens Antigens such as some polysaccharides have multiple repeating epitopes. Because of the arrangement of epitopes, clusters of B-cell receptors bind to the antigen simultaneously, leading to B-cell activation without the involvement of TH cells. (YY

Under what circumstances is having a fever beneficial? Under what circumstances is having a fever harmful? What are the actions of T cells? What are the actions of B cells?

What are some examples of innate defense mechanisms that are chemical in nature? What is complement?

What problems would arise if a person had a hereditary deficiency that resulted in an inability to present antigens to T cytotoxic cells? What would the problem be if the person had a deficiency in presenting antigen to generate Th 1 (T helper 1) cells or (T helper 2) cells? Could a person having any one of these deficiencies survive in a normal environment