ANTIGEN IN TISSUES .4. EFFECT OF ANTIBODY ON RETENTION AND LOCALIZATION OF ANTIGEN IN RAT LYMPH NODES

Abstract

A study was made of the role of specific antibody in causing increased retention and specific localization of a weak antigen, human serum albumin (HSA), in the popliteal and aortic lymph nodes of rats. The antigen was labelled with 1125 prior to mixing with antibody. HSA mixed with excess homologous antibody was trapped to the greatest extent in these nodes after footpad injection of the antigen. Injection of HSA with antibody caused increased uptake of HSA into the medulla but retention was poor as autoradio-graphs showed the area to be essentially free of antigen 4-5 days after injection. By contrast, antigen injected with antibody localized strongly in lymphoid follicles and persisted at this site. Both IgM [immuno-globulin M] and IgG [immunoglobulin G] antibody caused follicular localization of HSA in rats. Heterologous, isologous and homologous antibody also caused follicular localization of the antigen. Purified homologous gamma-globulin localized in the follicles. A moderate increase in the net negative charge of the gamma-globulin by acetyla-tion did not appreciably affect the ability of the globulin to localize in the follicles. Detectable formation of antibody did not occur in the rats after injection of antigen-antibody complexes, owing possibly to the inhibitory effect of free antibody on the primary response.