POLYMORPHISM OF MHC-DRB ALLELES IN CERCOPITHECUS-AETHIOPS (GREEN MONKEY) - GENERATION AND FUNCTIONALITY

DRB genes have been studied for the first lime in green monkeys (Cerco pithecus aethiops). Eleven new DRB alleles (exon 2, exon 3) have been obtained and sequenced from cDNA. A limited number of lineages have be en identified: DRB103 (4 alleles), DRB1*07 (3 alleles), DRB5 (1 allel e), DRBw6 (1 allele), and DRB1*w7 (2 alleles). The existence of Ceae- DRB1 duplications is supported by the finding of 3 DRB1 alleles in 3 d ifferent individuals. Ceae-DRB10701 may be non-functional because it bears serine at position 82, which hinders molecule surface expression in mice; the allele is only found in Ceae-DRB duplicated haplotypes. Base changes in cDNA Ceae-DRB alleles are consistent with the generati on of polymorphism by point mutations or short segment exchanges betwe en alleles. The eleven green monkey DRB alleles meet the requirements for functionality as antigen-presenting molecules (Perhaps, excluding DRB10701), since: 1) they have been isolated from cDNA and do not pre sent deletions, insertions or stop codons: 2) structural motifs necess ary for a correct folding of the molecule, for the formation of DR/DR dimers and for CD4 interactions are conserved, and 3) the number of no n-synonymous substitutions is higher than the number of synonymous sub stitutions in the peptide binding region (PBR), while the contrary hol ds true for the non-PBR region.