Immunoglobulin G subclass restriction of antibodies against hepatitis B surface antigen

Immunoglobulin G (IgG) antibodies against hepatitis B surface antigen were found to be restricted to subclasses IgG1 and IgG3 in serum samples of 17 individuals. Quantitative determinations showed that in 10 samples the minor serum subclass IgG3 contained more antibodies than the predominant subclass IgG1. Ranges of concentrations were between 0.72 and 16.50 micrograms/ml for IgG3 antibodies and between 0.55 and 6.19 micrograms/ml for antibodies of subclass IgG1.