Proportions of IgG subclasses in antibodies formed during vaccination with hepatitis B surface antigen

Nineteen healthy adults were given three injections of hepatitis B vaccine (days 0, 30, and 180), and serum samples were obtained on days 0, 21, 51, and 201. A fourfold or greater increase of IgG antibodies within 201 days was detected in 18 individuals (geometrical mean increase 26-fold), but final IgG antibody concentrations (0.3-3 micrograms/ml) were low. Some vaccines had almost reached peak concentration on day 21, in others a great increase was observed between days 21 and 51, and in a few individuals between days 51 and 201. IgG1 was the predominant subclass in the antibodies of most individuals. Ninety-five per cent of all IgG antibodies were IgG1 in early samples of early responders. In late samples of all vaccinees the average proportion of IgG1 antibodies was 78%. The proportion of IgG2 antibodies was slightly higher in late samples (average 12%) than in the early samples of the early responders, (average less than 6%, P less than 0.05). Considerable amounts of IgG3 and IgG4 antibodies were found in one vaccine, but on the average the proportion of IgG3 or IgG4 antibodies was low (less than 6%).