Detection, immunoabsorption, and inhibition of cytotoxic activity of anti‐αGal antibodies using newly developed substances with synthetic Gal α1–3Gal disaccharide epitopes

Academic Article

Abstract

  • Abstract: The presence of naturally occurring anti‐Galα1–3Gal (anti‐αGal) antibodies in human serum is believed to be a major factor in the hyperacute rejection of discordant organ xenografts such as the pig‐to‐human combination. Galα1–3Gal epitopes are expressed on pig tissues and the binding of anti‐αGal leads to endothelial cell activation and complement‐mediated, hyperacute graft rejection. One possible method to overcome this problem is to absorb anti‐αGal antibodies from the plasma of the xenograft recipient using a suitable immunoabsorbent or to interfere with their binding to tissues and thus prevent their cytotoxic activity by the intravenous injection of soluble antigen. We describe here the use of new synthetic antigens containing the Galα1–3Gal disaccharide (Bdi) epitope. Soluble conjugates of the Bdi with polyacrylamide (PAA‐Bdi) were used as coating antigens for an anti‐αGal ELISA as well as for in vitro inhibition of the cytotoxicity of anti‐αGal. An immunoabsorbent consisting of PAA‐Bdi coupled to macroporous glass (Sorbent Bdi) was tested for absorption of anti‐αGal from human serum. Anti‐αGal IgM, IgG and IgA could be detected by the anti‐αGal ELISA and were specifically absorbed by Sorbent Bdi with absorption efficiencies ranging from 70 to 50% for anti‐αGal IgG and 60 to 25% for anti‐αGal IgM. A comparison of the anti‐αGal absorption by Sorbent Bdi and rabbit red blood cells revealed a qualitatively (isotype distribution) and quantitatively similar pattern. Nonspecific absorption by Sorbent Bdi was low, as detected by the reduction of anti‐A trisaccharide antibodies. The cytotoxic effect of human serum on pig kidney (PK15) cells was almost totally inhibited by the addition of synthetic B disaccharide or by adsorption of the serum through immunoaffinity columns of PAA‐Bdi. We conclude that the newly developed, synthetic αGal1–3Gal antigens are suitable for the detection and immunoabsorption or inhibition of anti‐αGal antibodies. © 1995 Munksgaard
  • Authors

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    Author List

  • Rieben R; von Allmen E; Korchagina EY; Nydegger UE; Neethling FA; Kujundzic M; Koren E; Bovin NV; Cooper DKC
  • Start Page

  • 98
  • End Page

  • 106
  • Volume

  • 2
  • Issue

  • 2