Two general classes of helper T cells are defined by the cytokines they secrete. Promote T cell responses ii. D. Antibody is a serum protein which binds to a single molecular structure and then causes a biological effect that results in removal of that substance from the body. Antibodies are the products of B cells. Helper T cells are required for the production of antibodies from B cells.
Antibodies come in different classes, based on the constant region structure.
IgM. Arises first in the antibody response, very large molecule, good initiator of complement. Predominant antibody class found in the circulation. IgA. Found in serum and at mucosal surfaces. Prevents microbial adhesion at mucosal sites. Initiates allergic responses.