IDENTIFICATION OF A 40-KDA HUMAN PROTEIN THAT CROSS-REACTS WITH PROKARYOTIC HSP60 CHAPERONINS

Cross-reactivity between the immunodominant bacterial hsp60 proteins a nd heterologous human target proteins has led to numerous hypotheses o n the role of hsp60 in the pathogenesis of autoimmune disease. In this work, we describe a novel 40-kDa human protein that crossreacts with bacterial hsp60 proteins. CCP40 (chaperone cross-reacting protein, 40- kDa) was identified in extracts from HL-60 (human promyelocytic leukem ia) cells on Western blots probed with A57-E4, a monoclonal antibody s pecifying a linear polypeptide epitope common among the bacterial hsp6 0 proteins (Yuan et. al. (1992) Inf. Immun. 60, 2288-2296). CCP40 was detected in other human hematopoietic cell lines, but could not be det ected in mature peripheral blood leukocytes. CCP40 was also expressed in human CD34+ peripheral blood progenitor cells, disappearing with cy tokine-induced cellular maturation. (C) 1995 Academic Press. Inc.