Cross reactivity of human beta2-microglobulin with human granulocyte colony-stimulating activity

Effects of antisera to human beta2-microglobulin (beta2 m) on factors able to stimulate colony formation in culture by human granulopoietic progenitor cells were investigated. The colony-stimulating activity (CSA) present in media conditioned by cultures of human peripheral leukocytes was suppressed by treatment with anti-beta2m. This inhibition was not due to a direct effect on the granulopietic progenitor cells; controls to test for cytotoxicity and for noncytotoxic inhibition of the progenitor cells by anti-beta2m yielded negative results. These experiments provide evidence for a relationship between human CSA and beta-microglobulin, and suggest a possible analogy between molceules involved in the in vitro regulation of granulopoiesis and products of the major histocompatibility gene complex.