SPECIFIC DEPLETION OF PREFORMED IgM NATURAL ANTIBODIES BY ADMINISTRATION OF ANTI-?? MONOCLONAL ANTIBODY SUPPRESSES HYPERACUTE REJECTION OF PIG TO BABOON RENAL XENOGRAFTS1

Abstract

Specific elimination of natural anti-porcine IgM antibodies allows to avoid HAVR of a pig to baboon renal xenograft, whereas anti-porcine IgG antibodies and complement proteins were present in the serum. This result confirms previous in vitro reports and demonstrates for the first time in vivo that preformed IgM antibodies alone are responsible for HAVR, while preformed anti-porcine IgG antibodies are unable alone to cause HAVR. Anti-IgM therapy appears as an important tool to transiently but completely eliminates xeno-IgM antibodies in vivo.