Xenogeneic iso-skin graft and mixed lymphocyte reaction studies using HLA-DP transgenic mice.
To elucidate the cellular responses against xeno-MHC antigens, in vitro mixed lymphocyte culture (MLC) and in vivo skin grafting (SG) studies were conducted using HLA-DP transgenic mice (B6-DP mice). Xenogenic iso-(B6-DP to B6 mice) MLC showed positive but much lower responses compared to allo-MLC responses. Nevertheless, B6-DP skin grafts were rejected in a similar time course as allo-skin grafts. To examine mechanisms underlining skin graft rejection, both in vitro cytotoxic lymphocyte (CTL) responses and delayed-type hypersensitivity (DTH) reactions were tested. The studies showed that DTH but not CTL reactions were involved for the graft rejection. SG was again conducted after the administration of anti-CD4 and/or CD8 monoclonal antibody (mAb). Mice treated with both CD4 and CD8 mAb accepted B6-DP SG for as long as up to 60 days and those treated with either CD4 or CD8 mAb alone rejected skin grafts on its own most of the time (75% in anti-CD4 mAb treated mice, 88.9% in anti-CD8 mAb treated mice), which suggests that the strict T cell restrictions for xeno-DP antigens do not exist. Even in these finally rejected cases, longer median survival time and final rejection time were observed, and in the other mice (25% in anti-CD4 mAb treated, and 11.1% in anti-CD8 mAb treated mice), graft acceptance was found. Therefore, it was suggested that the immunological reactions leading to the graft rejection occurs most efficiently when both T cell subsets are present. The above results indicate that xenogeneic HLA-DP antigens could act as significant transplantation antigens equivalent to alloantigens despite their lower stimulative activity in vitro, and also support the interpretation that DP antigens act like a minor histocompatibility antigen beyond the difference of species. Monomorphic anti-HLA class II antibodies were detected in recipients' sera as early as 2 weeks and even at 6 months, indicating that xeno-MHC antigens are prone to be memorized to B cells. It was concluded that HLA transgenic mice are useful for the investigation of cellular responses across xeno-MHC barriers.
Hagihara
M
M
Department of Transplantation Immunology, Tokai University School of Medicine, Kanagawa, Japan.
Shimura
T
T
Takebe
K
K
Munkhbat
B
B
Sato
T
T
Tsuchida
F
F
Sato
K
K
Tsuji
K
K
D000818:Animals; D000906:Antibodies / Q000032:analysis; D016516:CD4-CD8 Ratio; D006682:HLA-DP Antigens; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006968:Hypersensitivity, Delayed / Q000276:immunology; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008822:Mice, Transgenic / Q000276:immunology*; D012867:Skin / Q000276:immunology; D016038:Skin Transplantation / Q000276:immunology* / Q000473:pathology; D013154:Spleen / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014183:Transplantation, Heterologous; D014185:Transplantation, Isogeneic
D000906:Antibodies; D006682:HLA-DP Antigens; D000949:Histocompatibility Antigens Class II