title: Presence of intrinsic B lymphocyte tolerance in mixed but not in complete semiallogeneic bone marrow chimeras.
abstract: The existence of intrinsic B lymphocyte transplantation tolerance was investigated in murine semiallogeneic complete and mixed bone marrow chimeras. Complete chimeras (CC), which were obtained by infusing 20x10(6) C57BL/10 (P1) bone marrow (BM) cells into irradiated (10.5 Gy) (C57BL/10xBALB/c) F1 recipients, were repopulated for 100% with P1 lymphohematopoietic cells. In mixed chimeras (MC), which were obtained by injection of 15 x 10(6) P1 together with 5 x 10(6) F1 BM cells, between 15% and 40% of F1 lymphohematopoietic cells persisted after BM transplantation. Neither MC nor CC were able to develop significant T cell immunity (mixed lymphocyte reaction) or B cell immunity (IgG alloantibodies) against the mismatched host antigens (BALB/c), despite repetitive immunizations. However, after immunization with third-party cells (C3H), the IgG alloantibodies raised cross-reacted with the host-type (BALB/c) antigens in the CC but not in the MC. This suggested that intrinsic B lymphocyte tolerance for host antigens had occurred in MC but not in CC. This was further evidenced in transfer experiments using lethally irradiated C57BL/10 mice reconstituted with purified control C57BL/10 T lymphocytes together with purified C57BL/10 B lymphocytes isolated from CC or MC. Only the recipients reconstituted with B lymphocytes from CC, and not those from MC, produced anti-BALB/c IgG alloantibodies after immunization. These results show that intrinsic B lymphocyte tolerance can be achieved after transplantation and that this depends on the presence of lymphohemopoietic cells expressing the tolerogens.
authors.affiliation: Division of Nephrology, University of Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Salam
authors.forename: J
authors.initials: J
authors.lastname: Moodley
authors.forename: M
authors.initials: M
authors.lastname: Waer
mesh_terms: D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology*; D016026:Bone Marrow Transplantation; D002678:Chimera; D007111:Immunity, Cellular; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018183:Transplantation Chimera