Heat-killed Bacillus subtilis inhibits T-cell proliferative response to mitogens and recall antigens.
Heat-killed vegetative forms of Bacillus subtilis were found to impair considerably the capacity of human T-lymphocytes to secrete interleukin-2 (IL-2) and to proliferate (in terms of [3H]thymidine incorporation) after phytohaemagglutinin (PHA) stimulation. B. subtilis was also found to interfere with T-cell proliferation induced by concanavalin A (Con A) and the recall antigen tetanus toxoid (TT). The suppressive activity was dependent on bacterial concentration, and was not ascribed to mitogen, medium-nutrient absorption or cell killing. Moreover, B. subtilis did not interfere with mitogen-induced IL-2 receptor expression on the T-cell surface. On the other hand, B. subtilis did not interfere with T-cell proliferation induced by phorbol myristate acetate (PMA) and ionomycin stimulation. All data obtained suggest the binding of B. subtilis subcomponents to- or very close to-the T-cell receptor (TCR). Identification and purification of the basic structure(s) or component(s) of B. subtilis with TCR antagonist activity in vitro will help to exploit different aspects of T-cell activity and development, and possibly, will provide a means of specific control or modification of the immune response.
Gao
J
J
Institute of Microbiology, University of Brescia, School of Medicine, Italy.
Caruso
A
A
de Francesco
M
M
Canaris
A D
AD
Licenziati
S
S
Corulli
M
M
Dima
F
F
Fallacara
F
F
Savio
L
L
Martinelli
F
F
Fiorentini
S
S
Gargiuld
F
F
Turano
A
A
D001412:Bacillus subtilis / Q000276:immunology*; D001428:Bacterial Vaccines; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D003208:Concanavalin A; D005434:Flow Cytometry; D006358:Hot Temperature; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology; D015759:Ionomycin / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000166:cytology; D008213:Lymphocyte Activation / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D008934:Mitogens / Q000502:physiology; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology*; D013745:Tetanus Toxoid / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate
D001428:Bacterial Vaccines; D007376:Interleukin-2; D008934:Mitogens; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2; D013745:Tetanus Toxoid; D003208:Concanavalin A; D015759:Ionomycin; D013755:Tetradecanoylphorbol Acetate