Antibody isotypes of mammals Name Types Description Antibody complexes 2 M exposed to antige ooaivabasophand .g antimicro Binds to allerg 1 gens and triggershistamine release frommast cellsand -≤ In is four forms,provides the mjority of antibody-based immuiy Expressed on the surface of B cells(monomer)and in a secreted form gM ges of Bumoral)immunity before there is srien Antibody isotypes not found in mammals Name Types Description IgY Found inbirds and reptiles;related to mammalian Igw Found insharks and skates related to mammalian ID Structure lobular che critically can modulate an antibody's affinity for its corresponding FcR(s). The basic functional unit of each antibody isan imm with unoglobulin(Ig)m with fish IgM,or pentameric with five Ig units,like mam malian IgM.(2 The variable parts of an antibody are its Vregions,and the constant part is its C region Immunoglobulin domains The monomer shped moleculehatsf opolypepide chainseichns Each chain is composed of structural domains n domains.The contain about 70 s and are clas d 23 fold in whichw a"sandwich"shape.held together by interactions between conserved cysteines and other charged amino acids. Heavy chain