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R Makida

Publications and source records attributed to R Makida.

3 recordsLinked to original sources

Association of toxic shock syndrome toxin-secreting and exfoliative toxin-secreting Staphylococcus aureus with Kawasaki syndrome complicated by coronary artery disease.

Kawasaki syndrome (KS) has been reported to be associated with selective expansion of Vbeta2+ T cells and either staphylococcal toxic shock syndrome toxin-1 or streptococcal pyrogenic exotoxin C in uncomplicated cases. However, there have been no previous studies on the role of superantigens in KS associated with coronary artery disease, the major complication of this illness. The present study characterized bacteria isolated from three acute KS patients who developed coronary artery disease. Staphylococcus aureus secreting either TSST-1 (n = 3) or exfoliative toxin A (n = 1), both known to stimulate expansion of Vbeta2+ T cells, were isolated from all three patients. The percent Vbeta2+ T cells was determined in three patients with coronary artery disease. On presentation, one patient demonstrated reduction, whereas the other two showed expansion, of Vbeta2+ T cells. Repeat analyses of the latter two children showed their percent Vbeta2+ T cells to decrease toward normal. These observations suggest that coronary artery disease in KS may result from superantigenic stimulation of Vbeta2+ T cells. This is also the first demonstration of an association of staphylococcal exfoliative toxin with acute KS. The observation that three different bacterial toxins associated with KS are potent activators of Vbeta2+ T cells suggests an important role for this T cell subset in the pathogenesis of this autoimmune disease.

Aneurysm↗

Bacterial superantigens induce V beta-specific T cell receptor internalization.

Staphylococcal enterotoxins can cause toxic shock syndrome and autoimmune diseases. Circulating T cells from these diseases have a very wide range of expression in particular T cell receptor (TCR) beta chain variable regions (V beta). One possibility for this wide range of TCR V beta expression is that during acute infection with organisms secreting superantigens (SAg) these potent molecules might modulate TCR expression. To test this hypothesis, we investigated the potential effects of SAg on TCR V beta cell surface expression. Peripheral blood mononuclear cells (PBMC) from healthy donors were incubated with staphylococcal SAg. Toxic shock syndrome toxin-1 (TSST-1) induced downregulation of V beta 2 expression, whereas staphylococcal enterotoxin (SE) B induced V beta 3-and V beta 12-specific downregulation. TSST-1 did not interfere with anti-V beta 2 mAb binding. Therefore, this downregulation was not due to steric hindrance of Ab binding by TSST-1. TSST-1 induced V beta 2 downregulation was time-, dose- and temperature-dependent. CD3 expression decreased in parallel with reduction of V beta expression. CD4 and CD8 expression were only slightly decreased. CD2, CD25 and HLA-DR expression were upregulated following TSST-1 stimulation of T cell lines. To investigate the fate of TCR after toxin stimulation, V beta 8+ Jurkat T cells were incubated with SEE which is known to stimulate V beta 8+ T cells, and analysed with fluoresence microscopy, and immunoprecipitation and Western blotting. After SEE stimulation, there was an increase in V beta 8 molecules found in the cytoplasm which correlated with loss of cell surface V beta 8 molecules, suggesting internalization of cell surface V beta 8 molecules was induced by SEE stimulation. Shedding of V beta 8 molecules into the culture supernatant was not detected. These data demonstrate that SAg mediated downregulation of TCR expression occurs primarily as the result of TCR internalization. This downregulation phenomenon may have physiological and pathological consequences in patients infected with Staphylococcus aureus.

Antibodies, Monoclonal↗