Proliferative response and cytokine production of bovine peripheral blood mononuclear cells induced by the superantigens staphylococcal enterotoxins and toxic shock syndrome toxin-1.
The potential of staphylococcal enterotoxin A (SEA), B (SEB), C(SEC) and toxic shock syndrome toxin-1 (TSST-1) to act as superantigens by inducing polyclonal T-cell mitogenesis and cytokine production was tested on bovine peripheral blood mononuclear cells (PBMC). These four toxins were capable of inducing strong proliferative response of PBMC from calves over a broad dosage range (1 pg/ml to 1 microgram/ml) in vitro. The toxin-activated blast cells consisted of both CD4+ T-cells and CD8+ T-cells, but the T-cell proliferation depended upon the presence of monocytes. Treatment of monocytes with monoclonal antibody to major histocompatibility complex class II antigens substantially inhibited the toxin-induced T-cell proliferative response, but paraformaldehyde-fixation did not abrogate the accessory function. SEA, SEB, SEC and TSST-1, all induced the in vitro release of interleukin-2, interferon gamma and tumor necrosis factor alpha in a dose dependent manner. The results indicate that SEA, SEB, SEC and TSST-1 are capable of acting as superantigens by stimulating bovine T-cells as shown in the human and murine systems. The possible implications of these toxins in the immunopathogenesis of bovine mastitis caused by the infection with Staphylococcus aureus are discussed.
D000818:Animals; D000831:Animals, Newborn; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001427:Bacterial Toxins; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004768:Enterotoxins / Q000494:pharmacology*; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013211:Staphylococcus aureus; D018089:Superantigens / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D000911:Antibodies, Monoclonal; D001427:Bacterial Toxins; D004768:Enterotoxins; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D018089:Superantigens; D014409:Tumor Necrosis Factor-alpha; C030107:enterotoxin F, Staphylococcal; D007371:Interferon-gamma