Distribution of IgG subclasses after anti-hepatitis B virus immunization with a recombinant vaccine.

ABSTRACT

To assess whether a different IgG subclass distribution was elicited in "low" and "high responders" after vaccination with recombinant hepatitis B virus surface antigen, we selected from 360 vaccine recipients 30 "low-responder" subjects, with anti-HBs levels of 10-160 mIU/ml, and 40 "high-responder" subjects, with anti-HBs levels greater than 10,000 mIU/ml. In both groups all IgG subclasses were elicited in the anti-HBs response and the greatest contribution was that of IgG1, followed by IgG2. IgG1 was significantly less represented after the second (58%) and third doses (61%) of vaccine in "low responders" compared with "high responders" (65% and 69%). The relative percentage of IgG2 was significantly higher after the second (33%) and third (30%) doses of vaccine in "low responders" than in "high responders" (29% and 26%). In "low responders" the age of vaccine recipients significantly influenced the anti-HBs IgG subclass distribution IgG2 and IgG4 production was positively correlated with age, whereas the opposite was observed for IgG1. These data support the evidence that (1) IgG1 and IgG2 subclasses are mainly involved in the specific anti-HBs response both in "high" and "low responders"; (2) the relative contribution of specific IgG2 to vaccination is higher in low responders and progressively increases with age.