Characterization of the Three Immunoglobulin G Subclasses of Macaques

Southern blot experiments with genomic DNA samples of rhesus monkeys and crab-eating macaques and human C gamma-specific probes indicated that the two macaque species studied here possessed three C gamma genes per haploid genome. By amplifying the cDNA from macaque–mouse hybridomas, the coding sequences of two different rhesus monkey immunoglobulin (Ig)G subclasses, IgG1rh (Cγ1rh) and IgG2rh (Cγ2rh), and one crab-eating macaque IgG subclass IgG1mafa (Cγ1mafa), were characterized. None of the 16 rhesus monkey–mouse hybridomas studied here secreted IgG of the third subclass IgG3rh (Cγ3rh). The Cγ3rh gene was partly characterized at the genomic level. The cDNA of the Cγ3rh gene was amplified from mRNA of rhesus monkey peripheral blood mononuclear cells (PBMC). The results are analysed in terms of phylogenesis of the C gamma genes. The cDNA sequences coding for the Cμ and the Cκ domains of rhesus monkey Ig were established and compared to their human and non-human primate counterparts.