37-OR

Abstract

Aim Cynomolgus macaque (Macaca fascicularis = Mafa) and Rhesus macaque (Macaca mulatta = Mamu) are widely used as alternative nonhuman primate models for studying HIV, transplantation, and vaccines since they are anatomically and physiologically similar to humans. In this study we characterize naturally loaded peptides from two Mafa (A ∗ 31 & B ∗ 49) and one Mamu (B ∗ 47) class I molecule. Methods An MHC Class I-deficient human B cell line was transfected with Mafa and Mamu soluble MHC (sMHC) DNA constructs and selected with Geneticin. Clones were tested for sMHC class I production by ELISA, and “best producers” were single cell sorted, expanded, and retested. Cell pharms were seeded and 25 mg of class I MHC harvested. Mafa and Mamu class I MHC were purified by affinity chromatography, peptide ligands eluted in acetic acid, and the pooled peptide ligands were subjected to 14 cycles of Edman degradation. Pooled peptides were HPLC fractionated and subjected to nanospray mass spectrometry (MS) in order to characterize individual peptide ligands. Results MS analysis data show that Mafa molecules present peptides similar to those presented by human HLA class I molecules. The peptide lengths and source are consistent with previous reports of class I MHC. The two Mafa molecules in this study have peptide-binding motifs characteristic of HLA-B molecules while Mamu peptide ligands are not consistent with previously reported MHC class I. Conclusions Mafa class I molecules exhibit HLA-B-like cross-species peptide presentation, while Mamu class I molecules do not show similarities with human HLA class I molecules. The characterization of endogenously loaded Mafa-B ∗ 49 MHC class I peptides shows that it is comparable to human HLA-B ∗ 4405, and Mafa-A ∗ 31 to human HLA-B ∗ 1509 and B ∗ 1510. These data suggest that the MHC typing of Non-Human Primates for comparable MHC should proceed the use of these animal models when establishing correlates of immunity.