Identification of MhcMafa-DRB alleles in a cohort of cynomolgus macaques of Vietnamese origin

Dynamic evolution of Mhc haplotypes in cynomolgus macaques of different geographic origins

The major histocompatibility complex (MHC) plays a key role in immune defense, and the Mhc genes of cynomolgus macaque display a high degree of polymorphism. Based on their geographic distribution, different populations of cynomolgus macaques are recognized. Here we present the characterization of the Mhc class I and II repertoire of a large pedigreed group of cynomolgus macaques originating from the mainland north of the isthmus of Kra (N = 42). Segregation analyses resulted in the definition of 81 unreported Mafa-A/B/DRB/DQ/DP haplotypes, which include 32 previously unknown DRB regions. In addition, we report 13 newly defined Mafa-A/B/DRB/DQ/DP haplotypes in a group of cynomolgus macaques originating from the mainland south of the isthmus of Kra/Maritime Southeast Asia (N = 16). A relatively high level of sharing of Mafa-A (51%) and Mafa-B (40%) lineage groups is observed between the populations native to the north and the south of isthmus of Kra. At the allelic level, however, the Mafa-A/B haplotypes seem to be characteristic of a population. An overall comparison of all currently known data revealed that each geographic population has its own specific combinations of Mhc class I and II haplotypes. This illustrates the dynamic evolution of the cynomolgus macaque Mhc region, which was most likely generated by recombination and maintained by selection due to the differential pathogenic pressures encountered in different geographic areas.

Differential recombination dynamics within the MHC of macaque species

A panel of 15 carefully selected microsatellites (short tandem repeats, STRs) has allowed us to study segregation and haplotype stability in various macaque species. The STRs span the major histocompatibility complex (MHC) region and map in more detail from the centromeric part of the Mhc-A to the DR region. Two large panels of Indian rhesus and Indonesian/Indochinese cynomolgus macaques have been subjected to pedigree analysis, allowing the definition of 161 and 36 different haplotypes and the physical mapping of 10 and 5 recombination sites, respectively. Although most recombination sites within the studied section of the Indian rhesus monkey MHC are situated between the Mhc-A and Mhc-B regions, the resulting recombination rate for this genomic segment is low and similar to that in humans. In contrast, in Indonesian/Indochinese macaques, two recombination sites, which appear to be absent in rhesus macaques, map between the class III and II regions. As a result, the mean recombination frequency of the core MHC, Mhc-A to class II, is higher in Indonesian/Indochinese cynomolgus than in Indian rhesus macaques, but as such is comparable to that in humans. The present communication demonstrates that the dynamics of recombination 'hot/cold spots' in the MHC, as well as their frequencies, may differ substantially between highly related macaque species.

Study of MHC class II region polymorphism in the Filipino cynomolgus macaque population

The cynomolgus macaque (Macaca fascicularis) is currently used as an animal model in various fields of immunology especially in the development of innovative vaccines for the prevention and treatment of infectious diseases. The polymorphism of the major histocompatibility complex (MHC) influences the development of adaptive immune responses and it is crucial to characterize the polymorphism of cynomolgus MHC genes. We present here a systematic study of the MHC class II haplotypes in the Filipino macaque population. By the study of a large sample of Filipino animals (N = 353), we have characterized 18 MHC class II haplotypes by means of genotyping seven microsatellites. The animals were DRB genotyped by means of PCR-SSO or DGGE-sequencing on genomic amplified fragments. We cloned and sequenced the complementary DNA (cDNA) of DQA, DQB, DPA, and DPB genes of 117 animals. Combining the microsatellite genotyping and cDNA characterized in the 117 animals, we defined genetic association between the cDNA and the microsatellites and characterized 18 MHC class II haplotypes. For 104 animals out of the 353 studied, the presence of a recombinant haplotype was highly probable. Thirty-four percent of recombination was located in 256 kb segment between D6S2876 and D6S2747 microsatellites, a region encompassing several hot spots of recombination in the human MHC.