ANTIBODY RESPONSE TO IMMUNIZATION BY DIFFERENT ROUTES.

Rabbits were injected with human serum albumin once intravenously or intradermally with this antigen plus complete Freund adjuvant. The hemagglutinating titers of the antiserum and of the heavy and light antibody fractions were followed for several months. Circulation of heavy antibody in the intravenously injected group disappeared in 1 month, but in the intradermally injected group, it rose to a maximum titer, then declined, and then showed a second rise in titer. Light antibody showed increasing and then sustained titers over most of the time period. Heavy antibody failed to precipitate with antigen, even when it showed high hemagglutinating titers. Light antibody, in contrast, gave precipitation even when tested at much lower hemagglutination titers