{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T16:18:54Z","timestamp":1759335534661},"reference-count":0,"publisher":"Canadian Science Publishing","issue":"9","license":[{"start":{"date-parts":[[1992,9,1]],"date-time":"1992-09-01T00:00:00Z","timestamp":715305600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/www.nrcresearchpress.com\/page\/about\/CorporateTextAndDataMining"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Can. J. Microbiol."],"published-print":{"date-parts":[[1992,9,1]]},"abstract":"<jats:p> Staphylococcal toxic shock syndrome toxin-1 (TSST-1) as well as staphylococcal enterotoxin A (SEA) and B (SEB) have recently been shown to bind directly to the class II major histocompatibility antigen, HLA-DR. Whereas others have characterized TSST-1 and SEA binding to HLA-DR on transfected L cells or B lymphoma cell lines, we sought evidence for direct binding of TSST-1 and SEA to HLA-DR on purified human monocytes. A single class of high-affinity receptors was found for both TSST-1 (dissociation constant (K<jats:sub>d<\/jats:sub>) 40\u2002nM, 3.4\u2002\u00d7\u200210<jats:sup>4<\/jats:sup> receptors per cell) and SEA (K<jats:sub>d<\/jats:sub> 12\u2002nM, 3.2\u2002\u00d7\u200210<jats:sup>4<\/jats:sup> receptors per cell) on normal human monocytes. Affinity cross-linking of <jats:sup>125<\/jats:sup>I-labeled toxins to monocytes revealed the presence of two membrane protein subunits with molecular masses consistent with the \u03b1 and \u03b2 chains of human HLA-DR (35 and 28\u2002kDa, respectively). The anti-HLA-DR monoclonal antibody L243, but not L203 or 2.06, inhibited radiolabeled toxin binding to human monocytes and neutralized the mitogenic response of human T lymphocytes to both toxins. However, L243 was consistently more effective in blocking radiolabeled TSST-1 than SEA binding to human monocytes from the same donors, suggesting that TSST-1 and SEA may be binding to overlapping epitopes rather than to the same epitope on HLA-DR. Because TSST-1 and SEB bind to distinct epitopes on HLA-DR and because SEA cross competes with both TSST-1 and SEB on the HLA-DR receptor, we postulate that SEA occupies a binding site within HLA-DR that overlaps both TSST-1 and SEB. Future studies focused on receptor-mediated binding of these toxins to human monocytes and T lymphocytes from normal donors and toxic shock syndrome patients may reveal the underlying anomalies that predispose particular individuals to toxic shock syndrome. Key words: monocytes, staphylococcal toxic shock syndrome toxin-1, receptors, HLA-DR, staphylococcal enterotoxin A. <\/jats:p>","DOI":"10.1139\/m92-151","type":"journal-article","created":{"date-parts":[[2010,5,20]],"date-time":"2010-05-20T18:45:19Z","timestamp":1274381119000},"page":"937-944","source":"Crossref","is-referenced-by-count":7,"title":["Receptors for toxic shock syndrome toxin-1 and staphylococcal enterotoxin A on human blood monocytes"],"prefix":"10.1139","volume":"38","author":[{"given":"Raymond H.","family":"See","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gerald","family":"Krystal","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anthony W.","family":"Chow","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"155","container-title":["Canadian Journal of Microbiology"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/www.nrcresearchpress.com\/doi\/pdf\/10.1139\/m92-151","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,1,5]],"date-time":"2020-01-05T11:51:12Z","timestamp":1578225072000},"score":1,"resource":{"primary":{"URL":"http:\/\/www.nrcresearchpress.com\/doi\/10.1139\/m92-151"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1992,9,1]]},"references-count":0,"journal-issue":{"issue":"9","published-print":{"date-parts":[[1992,9,1]]}},"alternative-id":["10.1139\/m92-151"],"URL":"https:\/\/doi.org\/10.1139\/m92-151","relation":{},"ISSN":["0008-4166","1480-3275"],"issn-type":[{"value":"0008-4166","type":"print"},{"value":"1480-3275","type":"electronic"}],"subject":[],"published":{"date-parts":[[1992,9,1]]}}}