IDENTIFICATION OF A 65-KDA MANNOPROTEIN AS A MAIN TARGET OF HUMAN CELL-MEDIATED IMMUNE-RESPONSE TO CANDIDA-ALBICANS

To identify molecular targets of anticandidal cell-mediated immunity ( CMI) in humans, a highly immunogenic mannoprotein fraction (MP-F2) of Candida albicans was studied. SDS-PAGE and gel-permeation chromatograp hy separated MP-F2 into polydisperse mannoproteins of >200-31.5 kDa. H owever, only a 65-kDa constituent specifically induced proliferation o f human peripheral blood mononuclear cells (PBMC). Lymphoproliferation was accompanied by production of interleukin (IL)-1beta, interferon-g amma, and IL-6 but not IL-4. MP-F2- and MP-65-induced PBMC proliferati on was inhibited by an antagonist anti-T cell receptor antibody. Neith er the purified protein derivative of Mycobacterium tuberculosis nor M P-65 activated naive lymphocytes from umbilical cord blood, although t hese cells proliferated extensively in response to both phytohemagglut inin and IL-2. These data strongly suggest that MP-65 is an immunodomi nant mannoprotein antigen that is ordinarily expressed as a target of anti-Candida CMI in healthy humans.