Mycoplasma fermentans (Incognitus Strain) Cells Are Able to Fuse with T Lymphocytes

• Published in: Clinical infectious diseases 1993-08, Vol.17 (Supplement-1), p.S305-S308
• Main Authors: Dimitrov, D. S., Franzoso, G., Salman, M., Blumenthal, R., Tarshis, M., Barile, M. F., Rottem, S.
• Format: Article
• Language: English
• Subjects: Acquired Immunodeficiency Syndrome - etiology; Acquired Immunodeficiency Syndrome - microbiology; AIDS; AIDS/HIV; Bacteriology; Biological and medical sciences; Calcium - pharmacology; Cell fusion; Cell Line; Cell membranes; Endopeptidase K; Fluorescence; Fundamental and applied biological sciences. Psychology; HIV Infection, AIDS, and Mycoplasmal Infection in Immunocompromised Hosts; Humans; Lipids; Lymphocytes; Membrane Fusion - drug effects; Membrane Fusion - physiology; Microbiology; Mycoplasma; Mycoplasma fermentans - drug effects; Mycoplasma fermentans - pathogenicity; Mycoplasma fermentans - physiology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Polyethylene Glycols - pharmacology; Prokaryotic cells; Serine Endopeptidases - pharmacology; T lymphocytes; T-Lymphocytes - drug effects; T-Lymphocytes - microbiology; Viruses
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1093/clinids/17.Supplement_1.S305

Characteristics of the fusion of Mycoplasma fermentans (incognitus strain) with cultured lymphocytes were investigated. The rate and extent of fusion were monitored continuously in an assay that measured lipid mixing on the basis of dequenching of a fluorescent probe, octadecylrhodamine (R18), incorporated into mycoplasmas. Fusion of M. fermentans was detected with CD4+ (Molt-3) cells, CD4− (12E1) cells, and primary peripheral-blood lymphocytes. The level of fusion was relatively low (8%–12%). Detection of a similarly low level of fusion by fluorescence microscopy suggested the involvement of a specific lymphocyte subpopulation. After a short lag period, fusion at 37°C proceeded exponentially for ∼30 minutes and was virtually complete at 60 minutes. Throughout the process, lymphocytes remained intact. Fusion was stimulated by CaCl2 but not by MgCl2; its inhibition by antisera to M. fermentans and by pretreatment of M. fermentans with proteolytic enzymes implied that the mycoplasmas possessed a proteinase-sensitive receptor involved in fusion. Mycoplasmas were rendered nonfusogenic by treatment with the uncoupler CCCP (carbonyl cyanide m-chlorophenylhydrazone; 5 µM) but were unaffected by treatment with chlorpromazine (10 µM) or DCCD (dicyclohexylcarbodiimide; 50 µM); these findings suggested that a proton gradient across the cell membrane is required for fusion.