Recognizes a 60kDa protein, identified as the heat shock protein 60 (hsp60). Its epitope is localized between aa 383-447 of human hsp60. A wide variety of environmental and pathophysiological stressful conditions trigger the synthesis of a family of proteins known as heat shock proteins (hsp s), more appropriately called as stress response proteins (srp s). hsp60 is a potential antigen in a number of autoimmune diseases. In human arthritis and in experimentally induced arthritis in animals, disease development coincides with the development of immune reactivity directed against not only bacterial hsp60, but also against its mammalian homolog. Clone HSPD1/8398R, unlike LK2, recognizes only the mammalian (not bacterial) hsp60 and is useful in distinguishing hsp60 from mammals and bacteria.