RELATIONSHIPS BETWEEN ANTIBODIES AGAINST HUMAN SOLUBLE COMPLEMENT RECEPTOR-1 (HSCR1) FROM VARIOUS SPECIES

The relationships between antibodies against human soluble complement receptor 1 (hsCR1) were studied in rodents, dogs, nonhuman primates, a nd humans. An antibody response occurred in all species except humans. The anti-hsCR1 antibodies from the various species were characterized to determine if they recognize similar epitopes on the hsCR1 molecule . Dog and monkey sera, positive for hsCR1 binding, were used as blocki ng antibodies against mouse anti-hsCR1 monoclonal antibodies as well a s mouse and rat anti-hsCR1-positive sera. Human sera (blood group anti sera: anti-Knops, anti-McCoy, anti-Knops/McCoy, anti-Swain-langley) an d serum from one burn patient (who became seropositive despite ever re ceiving treatment with hsCRI) were also used to test blocking of mouse , rat, dog, and monkey antil-hsCR1. Characterization of anti-hsCR1 ant ibodies from different species demonstrated that hsCR1 causes divergen t antibody responses among animals. While mouse, rat, and dog antibodi es cross inhibit binding by approximately 50%, monkey antibodies recog nize primarily different epitopes of the hsCR1 molecule. Moreover, hum an antibodies binding hsCR1 are completely different from the animal a ntibodies, including monkey. This study indicates that although hsCR1 is immunogenic in animals, there is a difference in response between s pecies, particularly between nonprimates mates and primates, and final ly, that this antibody response is not predictive for humans.