Human anti-gamma-globulin antibodies specific for gamma G heavy chain subclasses.

Anti-γ-globulin antibodies which show specificity for γG and γG subclass antigens respectively have been detected in human sera. In contrast to most of the subclass antigens which are present in intact γ-globulin, these antigens are only revealed by pepsin digestion. This is the first test system employing anti-γ-globulin antibodies for determining γG subclasses of isolated antibodies and myeloma proteins. These anti-γ-globulins also react strongly with autologous pepsin-digested γG-globulin. The finding of human anti-γ-globulin antibodies with these fine specificities for γG subclasses and autologous γG-globulin suggests that their function is closely related to certain specific-γG antibody populations. The findings show that both γG and γG molecules have subclass specific antigenic structures which are revealed following pepsin digestion.