Effector Functions Mediated by Antibodies

A by the Fc of IgG is not easily visualized. Nevertheless, all functions represent properties peculiar to inununoglobulins, and the sites responsible for the interaction have been investigated to some extent. These properties have been found to be associated with the Fc fragment, and in some cases the localization has been further defined. Table IV lists the effector functions and the classes and subclasses they are associated with. 

It should be mentioned at this point that no definitive function has been found to be associated with the carbohydrate moieties of immunoglobulins, most of which are associated with the Fc fragment. Hinrichs and Smyth (1970) have obtained some evidence that a portion (40%) of rabbit IgG molecules bear a Ch2 oligosaccharide, and these are not transferred across the placental membrane. It is interesting that in human IgM, which is also known not to cross the placental membrane, the Ch2 oligosaccharide occupies a similar position, i.e., close to the inter-H-chain disulfide bond. Moreover, carbohydrate has been reported (Swenson and Kem, 1967 Melchers and Knopf, 1%7) to play a role in the 

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