Role of staphylococcal enterotoxins in pathogenesis of atopic dermatitis: growth and expression of T cell receptor V beta of peripheral blood mononuclear cells stimulated by enterotoxins A and B.
In order to investigate the role of staphylococcal enterotoxins in the pathogenesis of dermatitis in atopic patients, the growth and expression of T cell receptor V beta in peripheral blood mononuclear cells (PBMCs) from atopic dermatitis patients induced by stimulation with staphylococcal enterotoxin A (SEA) or staphylococcal enterotoxin B (SEB) were examined. Lymphocyte stimulation tests (LST) using SEA or SEB were performed in atopic dermatitis (AD) patients (n = 10) and normal controls (n = 5). PBMCs from AD patients displayed significantly stronger responses to SEA or SEB than those from the controls. To ascertain further whether SEA acts as a superantigen in atopic dermatitis, the expression of 22 genes in the variable region of the beta chain (V beta) of T cell receptors (TcR) was examined before and after stimulation with SEA by a reverse transcriptase-polymerase chain reaction (RT-PCR). Before stimulation, only weak expression of V beta was observed, and the expression of the various V beta segments was uniform in the normal controls (n = 3). In the AD patients (n = 3), the expression of V beta was enhanced, but was not uniform in 2 out of 3 patients and the pattern of expression was characteristic in each individual. This suggests that V beta expression varies in individual AD patients and displays restricted heterogeneity, reflecting the diversity of the etiology of the disease. After culture of the SEA-stimulated cells, no difference was observed in the expression of TcR V beta segments in the 3 normal controls as compared with that prior to stimulation, but particular V beta segments were intensely expressed in 3 AD patients, displaying distinct patterns (case I: V beta 9, V beta 10, V beta 18; case 2: V beta 6.1-3; case 3: V beta 6.1-3, V beta 18). Many of these V beta segments corresponded with those known to be induced by SEA. These results suggest oligoclonal proliferation of T cells in the peripheral blood of AD patients and high responsiveness in each clone, and since the expression of V beta segment after SEA stimulation was restricted, the actions of staphylococcal enterotoxins as superantigens were suggested.
Department of Dermatology, Kinki University School of Medicine, Osaka, Japan.
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D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D016022:Case-Control Studies; D002648:Child; D017931:DNA Primers / Q000235:genetics; D003876:Dermatitis, Atopic / Q000209:etiology* / Q000235:genetics / Q000276:immunology; D004768:Enterotoxins / Q000633:toxicity*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D016133:Polymerase Chain Reaction; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D013203:Staphylococcal Infections / Q000150:complications; D013211:Staphylococcus aureus / Q000472:pathogenicity
D017931:DNA Primers; D004768:Enterotoxins; D016693:Receptors, Antigen, T-Cell, alpha-beta; C026066:enterotoxin A, Staphylococcal; C031818:enterotoxin B, staphylococcal