Measurement of hemolytic complement and the third component of complement in nonhuman primates

Complement, determined by hemolytic assay, and the third component of complement (C3), determined by radial immunodiffusion assay, were measured in nine nonhuman primate species. The species studied were the titi (Callicebus mollach). The sooty mangabey (Cercocebus atys), the thick-tailed galago or bushbaby (Galago crassicaudatus panganiensis), the crab-eating monkey (Macaca fascicularis), the rhesus monkey (Macaca mulatta), the bonnet monkey (Macaca radiata), the stumptailed macaque (Macaca speciosa), the yellow baboon (Papio cynocephalus), and the black-and-red tamarin (Saguinus nigricollis). Both sheep and bovine erythrocytes were used in the hemolytic complement assays. With the sheep erythrocyte system, sera from four species (yellow baboon, sooty mangabey, bonnet monkey, black-and-red tamarin) had similar titers with both antibody sensitized and non-sensitized erythrocytes. In contrast, the titers obtained using sensitized bovine erythrocytes was always higher than the values obtained using non-sensitized bovine erythrocytes. In all species, the titers for non-sensitized sheep erythrocytes was higher than the titer for non-sensitized bovine erythrocytes. When the species were compared for cross reactivity using the radial immunodiffusion assay for human C3, the rhesus monkey showed the strongest cross reaction; the thick-tailed galago, a prosimian, showed no detectable cross reactivity; and the other species examined showed intermediate degrees of reactivity.