Identification of MHC I class genes in two Platyrrhini species

Abstract

The major histocompatibility complex is a diverse gene family that plays a crucial role in the adaptive immune system. In humans, the MHC class I genes consist of the classical loci of HLA-A, -B, and -C, and the nonclassical loci HLA-E, -F, and -G. In Platyrrhini species, few MHC class I genes have been described so far and were classified as MHC-E, MHC-F, and MHC-G, with MHC-G possibly representing a classical MHC class I locus while there were arguments about the existence of the MHC-B locus in Platyrrhini. In this study, MHC class I genes were identified in eight common marmosets (Callithrix jacchus) and two brown-headed spider monkeys (Ateles fusciceps). For common marmosets, 401 cDNA sequences were sequenced and 18 alleles were detected, including 14 Caja-G alleles and 4 Caja-B alleles. Five to eleven Caja-G alleles and one to three Caja-B alleles were detected in each animal. For brown-headed spider monkeys, 102 cDNA sequences were analyzed, and 9 new alleles were identified, including 5 Atfu-G and 4 Atfu-B alleles. Two or three Atfu-G and two Atfu-B alleles were obtained for each of animal. In phylogenetic analyses, the MHC-G and -B alleles from the two species and other Platyrrhini species show locus-specific clusters with bootstrap values of 86% and 50%. The results of pairwise sequence comparisons and an excess of non-synonymous nucleotide substitutions in the PBR region are consistent with the suggestion that Caja-G and Atfu-G may be classical MHC class I loci in the Platyrrhini species… But it appears that MHC-B locus of the two Platyrrhini species shares features with both classical and nonclasical MHC class I loci. Our results are an important addition to the limited MHC immunogenetic information available for the Platyrrhini species.

Gene conversion of the major histocompatibility complex class I Caja‐G in common marmosets (Callithrix jacchus)

“…Duplication of the MHC class I Caja‐B segment has already been observed, supporting the possibility of locus duplication, although further studies are required for verification. Contrary to previous publications, the Caja‐G alleles Caja‐G*07:01:01 , Caja‐G*08:01 , Caja‐G*08:23 and Caja‐G*18:04 were present in the majority of animals, seeming to have priority over others because of their high occurrence in individual unrelated animals. It can be speculated that 40 years of breeding that started from a relatively small group of breeding pairs in Europe might propagate such a phenomenon as major alleles.…”

“…In our study, 480 sequences of 21 common marmosets were analysed and classified as members of the Caja-G family. Comparison with already confirmed Caja-G sequences [26][27][28] resulted in 34 different alleles in our investigated group of animals. Four of the detected alleles have been published before 26,27 and a total of 30 new alleles, concerning the sequence of exon 1-4, were uploaded to the NCBI database and are presented in Table 1 with GenBank accession numbers, official IPD-MHC nomenclature and number of animals that shared the correspondent alleles.…”

“…The group of Cao et al . even detected up to 11 different alleles in a single common marmoset, which indicates that the variety of different alleles per animal may not be due to contamination but rather to the natural genotype . Duplication of the MHC class I Caja‐B segment has already been observed, supporting the possibility of locus duplication, although further studies are required for verification.…”

The response of common marmoset immunity against cedar pollen extract

“…Shiina et al determined the gene structure of Caja-G. The Caja-G gene cluster contains 14 loci, at least 5 of which express functional gene products (25); plural alleles have been found in these loci (26)(27)(28)(29). The variation and the binding of peptide suggested that it is more similar to classical HLA in humans, but the real function of Caja-G is yet to be clarified.…”

MHC class I-presented tumor antigen appraisable for T-cell responses against ovarian cancer

“…), of which the role is to transform the protein antigen into antigen peptides, present them to antigen-specific T lymphocytes, and implement antigen-antibody reaction, protecting the body from infection outside (Cao et al, 2015;Lisik et al, 2009). Many viruses can infect the skin and mucosa, and interfere with MHC-I antigen presentation process to evade the host immune response.…”