FURTHER STUDIES OF ANTIGEN STIMULATION OF DEOXYRIBONUCLEIC ACID SYNTHESIS IN RABBIT SPLEEN CELL CULTURES .2. EFFECTS OF SPECIFIC ANTIBODY

  • 1 January 1968
    • journal article
    • research article
    • Vol. 14  (3) , 415-+
Abstract
Insoluble immune complexes, prepared with heterologous protein antigens and homologous antibodies, affected the incorporation of [3H] thymidine into spleen cell suspension from rabbits immunized to these proteins. Low concentrations of such complexes stimulated thymidine uptake, (this being antigen specific), while high concentrations impaired the response to antigen. The inhibitory effect of high concentrations of immune complexes was non-specific as far as the responses to antigens were concerned, but the PHA-responsiveness of rabbit spleen cells was not significantly impaired by the presence of such complexes. When macrophages from the peritoneal cavities of normal rabbits were incubated with insoluble immune complexes and then washed, such cells were able to stimulate an antigen-specific response by spleen cells from immunized rabbits. The failure of spleen cells from immunized rabbits to respond to antigen in the presence of immune complexes may be the result of a direct inhibition of the mechanism of proliferation by these complexes. Inhibition of the response to antigen was also produced by the presence of free specific antibodies in the culture medium, even in excess of antigen. The antibody may have reacted with antigen present on the surfaces of cells, particularly macrophages, blocking the stimulatory mechanism.