Cell-mediated cytotoxicity to porcine aortic endothelial cells is not dependent on galactosyl residues when baboon peripheral blood lymphocytes are previously primed with pig xenoantigens.
BACKGROUND
In the pig-to-baboon model, acute vascular rejection remains the main hurdle for successful long-term xenograft survival. The production of galactosyl knockout pigs could solve concomitantly the problem of hyperacute and acute vascular rejection. This work studies in vitro the cell-mediated cytotoxicity of natural killer (NK) and T cells after priming of baboon peripheral blood lymphocytes (PBLs) with pig antigens to evaluate whether cytotoxicity is galactosyl-dependent.


METHODS
PBLs from naive and primed baboons were used as effectors on primary porcine aortic endothelial cells (PAECs) to assess cytotoxicity. Untreated or galactosidase-digested PAECs were used to evidence the role of galactosyl residues on cell-mediated cytotoxicity. Two rat-anti baboon monoclonal antibodies were tested to inhibit either T+NK cells (LO-CD2b) or NK cells alone (LO-CD94).


RESULTS
When using PBLs from naive animals, spontaneous lysis occurred and was inhibited by both LOCD-2b and LO-CD94. In comparison, lysis of PAECs was significantly higher when baboon PBLs were first primed in vivo with pig xenoantigens. In this case, cytotoxicity was completely inhibited by LO-CD2b but only partially by LO-CD94. Reduction of galactosyl residues by galactosidase digestion showed that PAEC lysis almost completely disappeared with naive baboon PBLs but not with primed baboon PBLs, thereby indicating that anti-pig T-cell response is not dependent on galactosyl residues.


CONCLUSIONS
Galactosyl knockout pigs could solve hyperacute rejection and also prevent the activation of NK cells even after xenogeneic priming. T cells will then be the next hurdle for the success of xenografting.
Dehoux
Jean-Paul
JP
Laboratory of Experimental Surgery, Faculty of Medicine, Université Catholique de Louvain, CHEX/5570, 55 Avenue Hippocrate, B-1200 Brussels, Belgium.
Nizet
Yannick
Y
de la Parra
Bernardo
B
Lecuivre
Corinne
C
Vergauwen
Martial
M
Bazin
Hervé
H
Latinne
Dominique
D
Gianello
Pierre
P
D000818:Animals; D015478:Antigens, Heterophile / Q000276:immunology*; D001011:Aorta; D002470:Cell Survival; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology* / Q000637:transplantation*; D007074:Immunoglobulin G / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D023421:Models, Animal; D010215:Papio; D051381:Rats; D013552:Swine; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D019172:Transplantation Conditioning / Q000379:methods; D014183:Transplantation, Heterologous / Q000276:immunology*; D000519:alpha-Galactosidase
D015478:Antigens, Heterophile; D007074:Immunoglobulin G; D000519:alpha-Galactosidase