Sequence and diversity of MHC DQA and DQB genes of the owl monkey Aotus nancymaae

The New World primate Aotus nancymaae has been recommended by the World Hea lth Organization (WHO) as a model for evaluation of malaria vaccine candida tes, given its susceptibility to experimental infection with the human mala ria parasites Plasmodium falciparum and Plasmodium vivax. We present here t he nucleotide sequences of the complete cDNA of MHC-DQA1 and of the polymor phic exon 2 segments of MHC-DQB1/DQB2. In a group of three nonrelated anima ls captured in the wild, five alleles of MHC-DQA1 could be identified. They all belong to one lineage, namely Aona-DQA1*27. This lineage has not been described in any other New World monkey species studied. In a group of 19 u nrelated animals, 14 Aona-DQB1 alleles could be identified which are groupe d into the two lineages Aona-DQB1*22 and Aona-DQB1*23. These lineages have been described previously in the common marmoset and cotton-top tamarin. In addition, two Aona-DQB2 sequences could be identified which are highly sim ilar to HLA-DQB2 sequences. Essential amino acid residues contributing to M HC DQ peptide binding pockets number 1 and 4 are conserved or semi-conserve d between HLA-DQ and Aona-DQ molecules, indicating a capacity to bind simil ar peptide repertoires. These results fully support the use of Aotus monkey s as an animal model for evaluation of future subunit vaccine candidates.