Abstract
Summary: The concentration of serum α- and β-globulins in rats remained within normal limits during the course of infection with Moloney virus. The γ-globulin concentration in such rats was normal at weaning age (4 weeks). However, the γ-globulin concentration did not increase normally as the animals matured, but remained at low levels throughout the life of the animal. The ability of the infected rat to produce IgM globulin appeared to be unimpaired. After immunization with S. typhi “O” antigen, a line corresponding to IgM appeared in both normal and infected rat serum. Agglutination titers to O antigen were comparable in both groups of rats. The antibody in the serum of infected rats was primarily mercaptoethanol sensitive while that in the serum of control rats consisted of both mercaptoethanol sensitive and mercaptoethanol resistant agglutinins.