Anti-Gal antibody-mediated skin graft rejection requires a threshold level of Gal expression

Abstract

Background: Despite overcoming xenograft hyperacute rejection (HAR), Gal (galactose-α1,3-galactose) expression may not be completely eliminated from the α1,3-galactosyltransferase gene knockout (Gal KO) pig because of alternative galactosyltransferases. Whether low levels of "residual" Gal are still susceptible to either complement fixing or non-complement fixing antibody beyond the HAR barrier remains unknown. Furthermore, it would be impossible to analyze the immune response specific to low-level Gal in a xenograft setting given the multitude of xenoantigens that could induce a recipient response. To investigate this question, we therefore used a skin graft model in BALB/c mice where the s..