Modulation of Ly49 D expression after allogeneic bone marrow transplantation and functional consequences.
Ly49 antigens, interacting with MHC class I molecules, enable NK cells to distinguish "self" from "non-self". Here, we investigated the activating receptor Ly49 D after allogeneic bone marrow transplantation (BMT). After transplantation of B6 bone marrow (BM) into BALB/c recipients we observed a significant reduction of Ly49 D+ NK cells and a decreased density of expression. We found a nonstochastic distribution of Ly49 D with Ly49 G2. In contrast to reduced coexpression with Ly49 A, a constant rate of Ly49 G2 on Ly49 D+ NK cells was observed in allogeneic chimeras. Cytotoxicity was reduced during the first two months after BMT After this time allogeneic chimeras showed tolerance against host-specific targets. We conclude that NK cells are able to shape their Lys49 repertoire fitting to a new environment after allogeneic BMT. This alteration seems to depend on the presence of new corresponding MHC class I molecules resulting in downregulation of respective receptors on donor cells. Analysing coexpression of Ly49 D and Ly49 G2, we found a relationship between these two receptors, showing a distinct effect after allogeneic BMT. Functional data indicate that a time of reduced NK cell cytotoxicity after BMT is followed by in vitro tolerance of allogeneic chimeras.
Abteilung Klinische Immunologie, Medizinische Hochschule Hannover, Germany.
Esther
E
Wilk
Simone
S
Korten
Margot
M
Zielinska-Skowronek
Reinhold E S
RE
Schmidt
Dirk
D
Meyer-Olson
D000818:Animals; D000950:Antigens, Ly / Q000096:biosynthesis / Q000235:genetics*; D016026:Bone Marrow Transplantation / Q000276:immunology*; D002678:Chimera / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D005260:Female; D007694:Killer Cells, Natural / Q000276:immunology; D037181:Lectins, C-Type; D008285:Major Histocompatibility Complex / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D055630:Receptors, NK Cell Lectin-Like; D014184:Transplantation, Homologous
D000950:Antigens, Ly; D037181:Lectins, C-Type; D055630:Receptors, NK Cell Lectin-Like