IgG1 HYPERGAMMAGLOBULINAEMIA IN CHRONIC PARASITIC INFECTIONS IN MICE: MAGNITUDE OF THE RESPONSE IN MICE INFECTED WITH VARIOUS PARASITES

Abstract

Mice chronically infected with 3 metazoan and 1 protozoan parasite contain in their circulation levels of IgG₁ which are increased over the levels in uninfected mice by at least 10. In the case of infection with the larval cestode, Mesocestoides corti. the serum IgG₁ concentration can reach > 50 mg/ml and, with a half-life of < 2 days, the number of cells engaged in IgG₁ production is approximately 2 10⁸. The IgG₁ hypergammaglobulinaemia is not seen in infected hypothymic nude mice. Biosynthetic labelling studies with organ and tissue cultures established that in two of the chronic infections the organs principally involved in IgG₁ synthesis were those pathologically involved or those "in line" for antigen capture: i.e. liver and spleen in the case of M. corti which is located in the liver and the peritoneal cavity, and various intestinal lymph nodes in the case of the gut-dwelling nematode, Nematospiroides dubius. This apparently exaggerated response to chronic parasitic infection is of interest simply because of the potential magnitude of the effect and the fact that it involves an Ig isotype with very poorly defined biological function.