The MHC systems in humans (HLA) and in other primate species have been studied extensively (Bontrop 2006) . The orthologues of the classical HLA-A and -B genes, which are involved in the presentation of intracellularly processed peptides to cytotoxic T cells, are present in the rhesus and cynomolgus macaque (Boyson et al. 1996; Krebs et al. 2005) . However, in these animals the genes have undergone several rounds of duplication and display copy number variation (Anzai et al. 2003; Daza-Vamenta et al. 2004; Otting et al. 2005) . Whereas in humans only one copy of the HLA-A and -B genes is present, in macaques seven A-like genes are distinguished. On each haplotype, one polymorphic gene is observed, named Mamu-A1 or Mafa-A1, in combination with one or two oligomorphic genes designated Mamuor Mafa-A2 up to -A7, respectively (Otting et al. 2007; Pendley et al. 2008; Campbell et al. 2009; Kita et al. 2009 ). The same organisation is also applicable to the pigtailed macaque (Macaca nemestrina) (Lafont et al. 2007; Wu et al. 2008) .