Inhibition of Candida-induced lymphocyte proliferation by antibody to Candida albicans

Antibodies to Candida albicans do not prevent the occurrence of candidal vulvovaginitis. To determine if antibodies may be involved in enhancing infectivity, the effects of purified rabbit anti-Candida immunoglobulin G (IgG) on the in vitro cellular immune response to this organism was examined. In four individuals, 50 micrograms/mL rabbit anti-Candida IgG, but not control rabbit IgG, inhibited the lymphocyte proliferative response to Candida antigens by a mean of 92.3%. The degree of inhibition was proportional to antibody concentration over a 5-25 micrograms/mL range. Addition of antibody at the initiation of Candida incubation with peripheral blood mononuclear cells or up to 48 hours later led to a 60-83% inhibition; antibody addition 24 hours before Candida caused only a 29% inhibition. Addition of antibody to purified macrophages concomitantly with Candida or after an overnight incubation of macrophages and Candida, both followed by the addition of lymphocytes, demonstrated that the uptake and/or processing of Candida antigens by macrophages and the recognition by lymphocytes of Candida antigen on the macrophage surface were both inhibited by antibody. Candida-specific antibody may enhance the ability of this organism to escape immune destruction.