title: Blocking activity of the serum from semiallogeneic chimaeras produced by means of cyclophosphamide.
abstract: Blocking activity of the serum from semiallogeneic chimaeras produced by the i.p. injection of cyclophosphamide, followed by the i.v. injection of 10(8) spleen cells from (CBA X C57B-L/6)F1 hybrid mice into CBA mice, was investigated. The chimaera serum was found to inhibit local GVHR when injected together with lymphocytes from CBA mice into (CBA X C57BL/6)F1 hybrid mice, but not (CBA X BALB/c)F1 hybrids. Previous absorption of the chimaera serum with C57BL/6 lymphocytes reduced its blocking activity in local GVHR. Absorption with activated CBA anti-C57BL/6 lymphocytes had no effect on blocking activity of the serum. In some experiments the chimaera serum inhibited cytotoxic activity of CBA anti-C57BL/6 and BALB/c anti-C57BL/6 lymphocytes on the corresponding target cells in vitro. Graft-versus-graft reaction of CBA thymocytes against spleen cells from (CBA X C57BL/6)F1 hybrid mice was considerably reduced when irradiated chimaeras were the recipients. Intravenous injection of the chimaera serum into the intact CBA mice did not prolong the survival of C57BL/6 skin allografts. It is concluded that the serum blocking factor is an antibody to the transplantation antigen or an antigen-antibody complex.
mesh_terms: D000818:Animals; D000906:Antibodies; D001667:Binding, Competitive; D002678:Chimera; D003513:Cycloheximide / Q000494:pharmacology*; D003602:Cytotoxicity, Immunologic; D005260:Female; D006087:Graft vs Host Reaction; D007108:Immune Tolerance / Q000187:drug effects*; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D016038:Skin Transplantation; D013154:Spleen / Q000276:immunology; D014184:Transplantation, Homologous
chemical_list: D000906:Antibodies; D003513:Cycloheximide