title: Double-negative T cells, activated by xenoantigen, lyse autologous B and T cells using a perforin/granzyme-dependent, Fas-Fas ligand-independent pathway.
abstract: The ability to control the response of B cells is of particular interest in xenotransplantation as Ab-mediated hyperacute and acute xenograft rejection are major obstacles in achieving long-term graft survival. Regulatory T cells have been proven to play a very important role in the regulation of immune responses to self or non-self Ags. Previous studies have shown that TCRalphabeta+CD3+CD4-CD8- (double-negative (DN)) T cells possess an immune regulatory function, capable of controlling antidonor T cell responses in allo- and xenotransplantation through Fas-Fas ligand interaction. In this study, we investigated the possibility that xenoreactive DNT cells suppress B cells. We found that DNT cells generated from wild-type C57BL/6 mice expressed B220 and CD25 after rat Ag stimulation. These xenoreactive B220+CD25+ DNT cells lysed activated, but not naive, B and T cells. This killing, which took place through cell-cell contact, required participation of adhesion molecules. Our results indicate that Fas ligand, TGF-beta, TNF-alpha, and TCR-MHC recognition was not involved in DNT cell-mediated syngenic cell killing, but instead this killing was mediated by perforin and granzymes. The xenoreactive DNT cells expressed high levels of granzymes in comparison to allo- or xenoreactive CD8+ T cells. Adoptive transfer of DNT cells in combination with early immune suppression by immunosuppressive analog of 15-deoxyspergualin, LF15-0195, significantly prolonged rat heart graft survival to 62.1 +/- 13.9 days in mice recipients. In conclusion, this study suggests that xenoreactive DNT cells can control B and T cell responses in perforin/granzyme-dependent mechanisms. DNT cells may be valuable in controlling B and T cell responses in xenotransplantation.
authors.affiliation: Department of Surgery, University of Western Ontario, London, Ontario, Canada. zhuxu.zhang@lhsc.on.ca
authors.forename: Zhu-Xu
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Yuexia
authors.initials: Y
authors.lastname: Ma
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Arp
authors.forename: Jifu
authors.initials: J
authors.lastname: Jiang
authors.forename: Xuyan
authors.initials: X
authors.lastname: Huang
authors.forename: Kathy M
authors.initials: KM
authors.lastname: He
authors.forename: Bertha
authors.initials: B
authors.lastname: Garcia
authors.forename: Joaquím
authors.initials: J
authors.lastname: Madrenas
authors.forename: Robert
authors.initials: R
authors.lastname: Zhong
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015478:Antigens, Heterophile / Q000008:administration & dosage / Q000502:physiology*; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002450:Cell Communication / Q000235:genetics / Q000276:immunology; D016923:Cell Death / Q000235:genetics / Q000276:immunology; D018920:Coculture Techniques; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D053222:Fas Ligand Protein / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D006085:Graft Survival / Q000235:genetics / Q000276:immunology; D053804:Granzymes / Q000502:physiology*; D016027:Heart Transplantation / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000637:transplantation; D019014:fas Receptor / Q000502:physiology*
chemical_list: D015478:Antigens, Heterophile; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D019014:fas Receptor; D054353:Perforin; D053804:Granzymes