The common marmoset: A new world primate species with limitedMhcclass II variability

Abstract

The common marmoset (Callithrix jacchus) is a New World primate species that is highly susceptible to fatal infections caused by various strains of bacteria. We present here a first step in the molecular characterization of the common marmoset's Mhc class II genes by nucleotide sequence analysis of the polymorphic exon 2 segments. For this study, genetic material was obtained from animals bred in captivity as well as in the wild. The results demonstrate that the common marmoset has, like other primates, apparently functional Mhc-DR and -DQ regions, but the Mhc-DP region has been inactivated. At the -DR and -DQ loci, only a limited number of lineages were detected. On the basis of the number of alleles found, the -DQA and -B loci appear to be oligomorphic, whereas only a moderate degree of polymorphism was observed for two of three Mhc-DRB loci. The contact residues in the peptide-binding site of the Caja-DRB1*03 lineage members are highly conserved, whereas the -DRB*W16 lineage members show more divergence in that respect. The latter locus encodes five oligomorphic lineages whose members are not observed in any other primate species studied, suggesting rapid evolution, as illustrated by frequent exchange of polymorphic motifs. All common marmosets tested were found to share one monomorphic type of Caja-DRB*W12 allele probably encoded by a separate locus. Common marmosets apparently lack haplotype polymorphism because the number of Caja-DRB loci present per haplotype appears to be constant. Despite this, however, an unexpectedly high number of allelic combinations are observed at the haplotypic level, suggesting that Caja-DRB alleles are exchanged frequently between chromosomes by recombination, promoting an optimal distribution of limited Mhc polymorphisms among individuals of a given population. This peculiar genetic make up, in combination with the limited variability of the major histocompatability complex class II repertoire, may contribute to the common marmoset's susceptibility to particular bacterial infections.

Unprecedented Polymorphism of Mhc-DRB Region Configurations in Rhesus Macaques

“…Hence, one would predict that primate species possessing limited or no polymorphism of -DRB region configurations would encode highly variable Mhc-DRB genes that are frequently exchanged by recombination. This has been documented for common marmosets, a New World monkey from the neotropical rain forests (32). In addition, the chicken has been reported to possess a "minimal essential Mhc" with two class II genes (43).…”

Quantitative MRI‐pathology correlations of brain white matter lesions developing in a non‐human primate model of multiple sclerosis

“…The mean lesion volume was 2.85 AE 1.28 mm 3 and the total lesion load 5.91 AE 4.68 mm 3 . Lesion appearance on brain MRI did not always coincide with an immediate increase of the neurological score.…”

“…Owing to the sharing of the MHC class II allele Caja-DRB Ã W 12 0 1 , 100% of monkeys are susceptible to the induction of experimental autoimmune encephalomyelitis (EAE), a widely accepted experimental model of the chronic inflammatory disease multiple sclerosis (MS) (3,4). The marmoset thus provides a useful preclinical model for basic research and for the efficacy testing of new therapies that fail to work in animal models more distinct from humans, such as rats and mice.…”

Myelin/Oligodendrocyte Glycoprotein-Induced Autoimmune Encephalomyelitis in Common Marmosets: The Encephalitogenic T Cell Epitope pMOG24–36 Is Presented by a Monomorphic MHC Class II Molecule

“…The molecular analysis of the Mhc class II genes of the common marmoset revealed functional Mhc-DR and -DQ regions, and an apparently inactivated Mhc-DP region (5). On basis of the number of alleles found, it was concluded that the Caja-DQA and -DQB loci are oligomorphic.…”

“…Genomic DNA was isolated from stable growing B cell lines, and exon 2 of the Caja-DRB genes was amplified by PCR (5). Sequence analysis was performed on an ABI prism 310 Genetic analyzer (Perkin-Elmer Applied Biosystems, Foster City, CA) using the ABI Prism dRhodamine terminator cycle sequencing ready reaction kit (Perkin-Elmer).…”