The orthologs of HLA-DQ and -DP genes display abundant levels of variability in macaque species.

The human major histocompatibility complex (MHC) region encodes three types of class II molecules designated HLA-DR, -DQ, and -DP. Both the HLA-DQ and -DP gene region comprise a duplicated tandem of A and B genes, whereas in macaques, only one set of genes is present per region. A substantial sequencing project on the DQ and DP genes in various macaque populations resulted in the detection of previously 304 unreported full-length alleles.

Complex MHC Class I Gene Transcription Profiles and Their Functional Impact in Orangutans.

MHC haplotypes of humans and the African great ape species have one copy of the MHC-A, -B, and -C genes. In contrast, MHC haplotypes of orangutans, the Asian great ape species, exhibit variation in the number of gene copies. An in-depth analysis of the MHC class I gene repertoire in the two orangutan species, Pongo abelii and Pongo pygmaeus, is presented in this article.

The repertoire of MHC class I genes in the common marmoset: evidence for functional plasticity.

In humans, the classical antigen presentation function of major histocompatibility complex (MHC) class I molecules is controlled by the human leukocyte antigen HLA -A, HLA-B and HLA-C loci. A similar observation has been made for great apes and Old World monkey species. In contrast, a New World monkey species such as the cotton-top tamarin (Saguinus oedipus) appears to employ the G locus for its classical antigen presentation function.

Haplotype diversity generated by ancient recombination-like events in the MHC of Indian rhesus macaques.

The Mamu-A, Mamu-B, and Mamu-DRB genes of the rhesus macaque show several levels of complexity such as allelic heterogeneity (polymorphism), copy number variation, differential segregation of genes/alleles present on a haplotype (diversity) and transcription level differences. A combination of techniques was implemented to screen a large panel of pedigreed Indian rhesus macaques (1,384 individuals representing the offspring of 137 founding animals) for haplotype diversity in an efficient and inexpensive manner. This approach allowed the definition of 140 haplotypes that display a relatively low degree of region variation as reflected by the presence of only 17 A, 18 B and 22 DRB types, respectively, exhibiting a global linkage disequilibrium comparable to that in humans.

The extreme plasticity of killer cell Ig-like receptor (KIR) haplotypes differentiates rhesus macaques from humans.

NK cells are essential in shaping immune responses and play an important role during pregnancy and in controlling infections. Killer cell immunoglobulin-like receptors (KIRs) educate the NK cell and determine its state of activation. Our goal was to determine how the KIR repertoire of the rhesus macaque (Macaca mulatta) has been shaped during evolution.

The mosaic of KIR haplotypes in rhesus macaques.

To further refine and improve biomedical research in rhesus macaques, it is necessary to increase our knowledge concerning both the degree of allelic variation (polymorphism) and diversity (gene copy number variation) in the killer cell immunoglobulin-like receptor (KIR) gene cluster. Pedigreed animals in particular should be studied, as segregation data will provide clues to the linkage of particular KIR genes/alleles segregating on a haplotype and to its gene content as well. A dual strategy allowed us to screen the presence and absence of genes and the corresponding transcripts, as well as to track differences in transcription levels.

Evidence for balancing selection acting on KIR2DL4 genotypes in rhesus macaques of Indian origin.

The interaction of killer-cell immunoglobulin-like receptors (KIR) and their respective major histocompatibility complex (MHC) ligands can alter the activation state of the natural killer (NK) cell. In both humans and rhesus macaques, particular types of non-classical MHC class I molecules are predominantly expressed on the trophoblast. In humans, human leukocyte antigen G has been demonstrated to act as a ligand for KIR2DL4, present on all NK cells, whereas Mamu-AG may execute a similar function in rhesus macaques.

Reactivation by exon shuffling of a conserved HLA-DR3-like pseudogene segment in a New World primate species.

The common marmoset (Callithrix jacchus), a New World monkey species with a limited MHC class II repertoire, is highly susceptible to certain bacterial infections. Genomic analysis of exon 2 sequences documented the existence of only one DRB region configuration harboring three loci. Two of these loci display moderate levels of allelic polymorphism, whereas the -DRB*W12 gene appears to be monomorphic.