HUMAN MONOCLONAL ANTI-D-INDUCED CLEARANCE OF HUMAN D-POSITIVE RED-CELLS IN A CHIMPANZEE MODEL

Two human monoclonal anti-Rh0(D) antibodies, one IgG1, and one IgG3, w ere tested for their ability to clear human D-positive red blood cells (RBCs) from chimpanzee circulation. Human RBCs (phenotype A1, R1r) fr om 1 donor were radiolabelled with chromium 51 and injected into 4 chi mpanzees. One day later the control animal received isotonic saline wh ereas 2 animals received 400 mug of purified human monoclonal anti-D, either IgG1 or IgG3. The remaining animal received both antibodies tog ether (200 mug of IgG1 and 200 mug of IgG3). Both individual antibody- mediated clearance of human D-positive cells and synergy was not obser ved when both antibodies were used in combination. IgG1 was slightly m ore effective than IgG3. This animal model is a suitable alternative f or conducting in vivo experiments in human beings, especially at the p reclinical study phase of monoclonal anti-D antibodies.