IgA
mucosal immunityMainly dimer also monomer, trimerSerum half life 6 day
IgD
Naive B cell antigen receptor.Monomer.Serum half life 3 day.
IgE
defense against parasitic worms, helminithic , present in allergic reactions., immediate hypersensitivity.Monomer. Serum half life 2 day. The least Serum concentration and the shortest half life.
IgG
crosses placentaOpsonization.Complement activation.Antibody dependent cell mediated.Cytotoxicity.Neonatal immunity.Feedback inhibition of B cells.Monomer 23 days Highest Serum concentration, longest half life.
IgM
Naive B cell antigen receptor(Monomeric Form ) , complement activation.Serum half life 5 dayPentamer