MHC class I allele frequencies in pigtail macaques of diverse origin

Pigtail macaques (Macaca nemestrina) are an increasingly common primate model for the study of human AIDS. Major Histocompatibility complex (MHC) class I-restricted CD8⁺ T cell responses are a critical part of the adaptive immune response to HIV-1 in humans and simian immunodeficiency virus (SIV) in macaques; however, MHC class I alleles have not yet been comprehensively characterized in pigtail macaques. The frequencies of ten previously defined alleles (four Mane-A and six Mane-B) were investigated in detail in 109 pigtail macaques using reference strand-mediated conformational analysis (RSCA). The macaques were derived from three separate breeding colonies in the USA, Indonesia and Australia, and allele frequencies were analysed within and between these groups. Mane-A*10, an allele that restricts the immunodominant SIV Gag epitope KP9, was the most common allele, present in 32.1% of the animals overall, with similar frequencies across the three cohorts. Additionally, RSCA identified a new allele (Mane-A*17) common to three Indonesian pigtail macaques responding to the same Gag CD8⁺ T cell epitope. This broad characterization of common MHC class I alleles in more than 100 pigtail macaques further develops this animal model for the study of virus-specific CD8⁺ T cell responses.