Human polypeptidic hormone-like substances in microorganisms

The presence of factors cross-reacting with polypeptidic human hormones (chorionic and pituitary gonadotropins, prolactin, ACTH and gastrin) has been studied with immune staining methods and agglutination tests in schizomycetes and protozoa of different origin. The bacteria strains freshly isolated from tumor patients do not react with the sera, whereas P. maltophilia ATCC 13637, some E. coli strains namely ATCC 12795, K12, 113/3, 1047, a free-living alga (O. malhamensis ATCC 11532) and a protozoon L. enrietti ATCC 30035 cross-react with the sera against hCG and its beta subunit. The last mentioned three bacterial strains (but neither the former one nor the eucaryotic microorganisms) react with rabbit sera raised against human pituitary gonadotropins, and a minority of this population react even with antibodies against human prolactin. B. mycoides ATCC 4004 reacts only with the latter antiserum. None of the examined microorganisms combines with antisera against other polypeptidic human hormones such as ACTH or gastrin. The bacterial production of hCG-like factor(s) by P. maltophilia is fairly high in Brain Heart Infusion Agar, disappears in cultures carried out in glucose-inorganic salt medium either plain or supplemented with growth factors or hCG beta-subunits, and is lost in tetracycline or chloramphenicol resistant mutans. The role played by joint sharing of antigens in conditioning the interaction between different organisms as well as the immune interfering properties of hCG are discussed.