alpha1,3-Galactosyltransferase gene-knockout miniature swine produce natural cytotoxic anti-Gal antibodies.
BACKGROUND
The expression of galactose alpha 1,3 galactose (Gal) in pigs has proved a barrier to xenotransplantation. Miniature swine lacking Gal (Gal pigs) have been produced by nuclear transfer/embryo transfer.


METHODS
The tissues of five Gal pigs of SLA dd haplotype (SLA) were tested for the presence of Gal epitopes by staining with the Griffonia simplicifolia IB4 lectin. Their sera were tested by flow cytometry for binding of IgM and IgG to peripheral blood mononuclear cells (PBMC) from wild-type (Gal) SLA-matched pigs; serum cytotoxicity was also assessed. The cellular responses of PBMC from Gal swine toward Gal SLA-matched PBMC were tested by mixed leukocyte reaction and cell-mediated lympholysis assays.


RESULTS
None of the tissues tested showed Gal expression. Sera from all five Gal pigs manifested IgM binding to Gal pig PBMC, and sera from three showed IgG binding. In all five cases, cytotoxicity to Gal cells could be demonstrated, which was lost after treatment of the sera with dithiothreitol, indicating IgM antibody-mediated cytotoxicity. PBMC from Gal swine had no proliferative or cytolytic T-cell response toward Gal SLA-matched PBMC.


CONCLUSIONS
Gal pigs do not express Gal epitopes and develop anti-Gal antibodies that are cytotoxic to Gal pig cells. The absence of an in vitro cellular immune response between Gal and Gal pigs is related to their identical SLA haplotype and indicates the absence of immunogenicity of Gal in T-cell responses. The model of Gal organ transplantation into a Gal SLA-matched recipient would be a valuable large animal model in the study of accommodation or B-cell tolerance.
Dor
Frank J M F
FJ
Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02129, USA.
Tseng
Yau-Lin
YL
Cheng
Jane
J
Moran
Kathleen
K
Sanderson
Todd M
TM
Lancos
Courtney J
CJ
Shimizu
Akira
A
Yamada
Kazuhiko
K
Awwad
Michel
M
Sachs
David H
DH
Hawley
Robert J
RJ
Schuurman
Henk-Jan
HJ
Cooper
David K C
DK
D000818:Animals; D000961:Antilymphocyte Serum / Q000276:immunology; D004187:Disaccharides / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005700:Galactosyltransferases / Q000235:genetics*; D006239:Haplotypes; D007108:Immune Tolerance / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D016296:Mutagenesis; D013552:Swine; D013556:Swine, Miniature; D014183:Transplantation, Heterologous / Q000276:immunology*
D000961:Antilymphocyte Serum; D004187:Disaccharides; D000939:Epitopes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C055075:galactosyl-(1-3)galactose; D005700:Galactosyltransferases