Trans-species activation of human T cells by rhesus macaque CD1b molecules.

Despite crucial importance of non-human primates as a model of human infectious diseases, group 1 CD1 genes and proteins have been poorly characterized in these species. Here, we isolated CD1A, CD1B, and CD1C cDNAs from rhesus macaque lymph nodes that encoded full-length CD1 proteins recognized specifically by monoclonal antibodies to human CD1a, CD1b, and CD1c molecules, respectively. The monkey group 1 CD1 isoforms contained amino acid residues and motifs known to be critical for intramolecular disulfide bond formation, N-linked glycosylation, and endosomal trafficking as in human group 1 CD1 molecules. Notably, monkey CD1b molecules were capable of presenting a mycobacterial glycolipid to human CD1b-restricted T cells, providing direct evidence for their antigen presentation function. This also detects for the first time a trans-species crossreaction mediated by group 1 CD1 molecules. Taken together, these results underscore substantial conservation of the group 1 CD1 system between humans and rhesus macaque monkeys.