Studies of biologic and serologic activities of rabbit-IgG antibody depleted of carbohydrate residues.

Abstract

Rabbit IgG preparations containing antibody activity against individual strains of Staphylococcus aureus, Escherichia coli, group A β-hemolytic streptococci, and pneumococci were digested with Diplococcus pneumoniae endoglycosidase enzyme with removal of more than half of Ig-associated carbohydrate. In addition specifically purified rabbit anti-bovine serum albumin (BSA) IgG was similarly treated. After carbohydrate removal no appreciable change in opsonic, complement fixing, or agglutinating activity was noted in anti-staphylococcal, anti-E. coli, or anti-streptococcal IgG preparations, whereas complete loss of both complement fixing and opsonic activity occurred with rabbit IgG containing anti-pneumococcal antibody activity. No change in passive cutaneous anaphylactic reactions was noted after carbohydrate depletion of immunoabsorbent isolated rabbit anti-BSA IgG antibody. These findings indicate heterogeneous influences of carbohydrate residues on biologic activities of various antibody populations.