title: Early cellular events in a systemic graft-vs.-host reaction. II. Autoradiographic estimates of the frequency of donor lymphocytes which respond to each Ag-B-determined antigenic complex.
abstract: A graft-vs.-host (GVH) reaction was initiated by the intravenous injection of parental strain (AO) lymphocytes into irradiated (AO times HO)F1 or (AO times DA)F1 hybrids. The proportion of donor T cells which had responded to the F1 hybrid antigens within 24 h was estimated by two methods. (a) Donor lymphocytes were labeled with [3H]uridine in vitro before injection. The proportion of labeled cells which had morphologically transformed in the recipient's spleen was 17-19%. In both series of experiments syngeneic transfers were performed in which case the proportion of transformed cells was 1-2.4%. A similar low proportion was found after parental to F1 transfer in a non-Ag-B strain combination. These figures were used to calculate the frequency of responding cells in the injected population given three additional pieces of information: (a) the extent of selection in the spleen which transformed the estimate to 4.5%-6.0% responders; (b) division of donor cells was shown to be negligible under the conditions of the experiment; and (c) the nonspecific recruitment of lymphocytes was shown to be negligible. A speculative model of antigen recognition by T cells which accounts for the high proportion of responders is outlined.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex; D001345:Autoradiography; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D003703:Demecolcine / Q000494:pharmacology; D006087:Graft vs Host Reaction; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D000644:Quaternary Ammonium Compounds; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology; D013897:Thoracic Duct / Q000276:immunology / Q000473:pathology; D013936:Thymidine; D013997:Time Factors; D014316:Tritium; D014529:Uridine; D014966:Xanthenes
chemical_list: D000936:Antigen-Antibody Complex; D000644:Quaternary Ammonium Compounds; D014966:Xanthenes; D014316:Tritium; D004247:DNA; D013936:Thymidine; D014529:Uridine; D003703:Demecolcine