IgG Subclasses in the Baboon ( Papio Cynocephalus )

Abstract

Heterogeneity of baboon (Papio cynocephalus) IgG, attributable to differences in the Fc regions of heavy chains, could be demonstrated by the use of specific antisera made in rabbits to isolated γ-chains. Four components of IgG were discernible in immunoelectrophoretic analysis. These antigenic determinants are not shared with man, as shown by absorption experiments with human globulin. The antigenic determinants are not polymorphic, but are a constant feature of the IgG of baboons from several distinct populations. Antibody activity to bovine serum albumin could be demonstrated in two or possibly all four of the components by radioimmunoelectrophoresis. These data support the conclusion that the baboon has four subclasses of IgG, which are delineated by antigenic determinants different from those delineating the human IgG subclasses. Preliminary evidence that these determinants are found in other monkey species is also presented.