Immunohistochemical localization of a choriogonadotropin-like protein in bacteria isolated from cancer patients

Abstract

By the use of specific antibody to human chorionic gonadotropin (CG) as well as to its β‐subunit, and the application of the indirect fluorescein‐labeled and peroxidase‐labeled antibody techniques, we have demonstrated the presence of a membrane (wall)‐associated CG‐similar immunoreactive protein in 15 strains of bacteria isolated from tissues of patients bearing malignant neoplasms. These microorganisms were classified as S. epidermidis, (12), E. coli (2), and a single strain of P. maltophilia (ATCC 13637). The absence of the CG‐like antigen in other “cancer associated bacteria”, Streptococcus faecalis (ATCC 12818) and Pseudomonas aeruginosa (from patient with cancer of colon), demonstrated that not every “cancer associated bacteria” has the capability to synthesize the trophoblastic‐like protein. The negative results obtained with a number of “noncancer control” bacteria of known origin, obtained from ATCC and from clinical samples, strongly supported the idea that the existence of these CG‐like protein producing microorganisms is not a ubiquitous finding. The demonstration of a de novo bacterial biosynthesis of a protein having similar antigenic and biophysical properties to those of the human trophoblastic hormone, has great biological implications, especially if its biosynthesis is proven only in bacterial strains growing in the presence of cancer cells in which we have already demonstrated the presence of a similar antigen. The explanation of the phenomenon is unknown. Because of their origin, the potential of “genetic exchange” with subsequent expression of the mammalian gene by the bacterial cells becomes a possibility. It is also possible that the gene coding for the CG‐like protein is normally present but inactive or repressed in all bacteria.

Human Choriogonadotropin-like Material in Bacteria of Different Species: Electron Microscopy and Immunocytochemical Studies with Monoclonal and Polyclonal Antibodies

“…For TEM studies, all bacteria (hCG-producers and controls) were grown aerobically in Trypticase soy broth at 35 "C for 18 h and subsequently fixed for a minimum of 2 h with cold (4 "C) 3% (w/v) glutaraldehyde in 0.1 M-phosphate buffer pH 7.4 containing 1 % (w/v) CaC12. Subsequent preparation of the specimens was as described by Acevedo et al (1981 h).…”

“…Most of those isolates were from cancer patients (Livingston & Alexander-Jackson, 1970;Cohen & Strampp, 1976;Acevedo et al, 1978Acevedo et al, , 1979Acevedo et al, , 1981Maruo et al, 1979;Backus & Affronti 1981 ;Domingue et al, 1986). These findings have important biological implications (Domingue et al, 1986) because (1) they constituted the first demonstration of the natural synthesis by prokaryotes of a biologically active material Abbreviations: hCG, human choriogonadotropin ; CWD, cell wall deficient; MoAb, monoclonal antibody; TEM, transmission electron microscopy.…”

Corticotropin/lipotropin common precursor-like material in normal rat extrapituitary tissues.

“…Livingston and Livingston (50), Cohen and Strampp (51), and Acevedo et al (52) have demonstrated that a human choriogonadotropin-like material is produced by bacteria, and our studies suggest § (53) that it is extractable from fish. LeRoith et al (53) have shown that bioactive ACTH and immunoactive A-endorphin were extractable from protozoa.…”

Production of choriogonadotropin-like factor by a microorganism.

“…Recently, Acevedo et al (22), using immunocytochemical techniques, reported that CG-like protein is present in several microorganisms that were isolated from patients bearing malignant neoplasms. However, these findings should be substantiated by other methods in view of the fact that subunits of glycoprotein hormones and serine proteases possess a homologous peptide sequence (23).…”