The effect of intradermal administration of Corynebacterium parvum on the immune response to hepatitis Bs antigen.

The immunopotentiating effect of the intradermal administration of a course of four doses (0.25 ml) of a standard suspension of killed C. parvum (2 mg/ml) was studied in a group of 10 asymptomatic chronic hepatitis B surface antigen (HBsAg) carriers, as well as in 11 persons with antibodies to HBsAg (anti-HBs) and six without HBsAg or anti-HBs. HBsAg, anti-HBs, and leukocyte migration inhibition (LMI) studies were performed in pre- and post-inoculation blood samples. C. parvum produced a substantial increase of anti-HBs titre in persons with preexisting anti-HBs. However, anti-HBs responses were not induced in carriers. HBsAg was not eliminated and its titre remained practically unchanged in carriers. These results support the hypothesis that in carriers the specific defect in the immune response to HBsAg possibly exists at the B cell level.