Immunological detection of hCG-like substances in aerobic bacteria of both tumour and non-tumour origin.

Production of hormone-like substances by prokaryotes and unicellular eukaryotes, as well as the presence of a human chorionic gonadotropin-like substance in the serum of individuals with malignancies, have been previously established. To determine the presence and distribution of the production of human chorionic gonadotropin (hCG) among aerobic bacteria, fourteen strains of bacteria of both tumour and non-tumour origin were examined using enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and indirect immunoperoxidase techniques. Of the six bacterial strains tested, half of the tumour-isolates produced an hCG-like substance while non-tumour associated strains of the same species did not do so. Virulent strains of two mycobacterial species also gave high positive values while avirulent Mycobacterium tuberculosis strains (H37Ra) yielded low or negative values. The production of hCG-like substances by mycobacteria, for which no tumour association is known, indicates that tumour association is neither a prerequisite nor a requirement for production of hCG. It appears that the presence of hCG-like substances is a variable character among bacterial species, suggesting that it may have been conserved throughout evolutionary history.