Evolutionary conservation of MHC class I and class II molecules—different yet the same

Kaufman, Jim; Salomonsen, Jan; Flajnik, Martin F.

doi:10.1006/smim.1994.1050

Cited by 157 publications

(156 citation statements)

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“…This is interesting in light of the existence of both fastidious and promiscuous peptide-binding clefts, as recently demonstrated in chickens and humans (58). Residues 24,26,34,45, and 67 surrounding residue 45 in the HLA-A2 a1 chain make up the so-called 45 pocket that influences the peptides bound, and are conserved in human alleles at the HLA-A or -C locus, while very diverse at the HLA-B locus (49). We examined these residues to compare the diversity within this region and see 26 variants of the pocket residues (24, 26, 34, 43, and 66, respectively).…”

Section: Discussionmentioning

confidence: 85%

“…Three of these residues are not perfectly conserved in our wild population. Arginine at position 83 instead of Y84 is typical of birds and other nonmammalian vertebrates (45,46). Y123 is replaced by phenylalanine, F124, or leucine, L124, and Y169 is replaced by histidine in six wild mallard alleles.…”

Section: Expressed Alleles Have Features Of Classical Mhc Class I H Cmentioning

confidence: 99%

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Extensive Allelic Diversity of MHC Class I in Wild Mallard Ducks

Fleming-Canepa

Jensen

Mesa

et al. 2016

The Journal of Immunology

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MHC class I is critically involved in defense against viruses, and diversity from polygeny and polymorphism contributes to the breadth of the immune response and health of the population. In this article, we examine MHC class I diversity in wild mallard ducks, the natural host and reservoir of influenza A viruses. We previously showed domestic ducks predominantly use UAA, one of five MHC class I genes, but whether biased expression is also true for wild mallards is unknown. Using RT-PCR from blood, we examined expressed MHC class I alleles from 38 wild mallards (Anas platyrhynchos) and identified 61 unique alleles, typically 1 or 2 expressed alleles in each individual. To determine whether expressed alleles correspond to UAA adjacent to TAP2 as in domestic ducks, we cloned and sequenced genomic UAA-TAP2 fragments from all mallards, which matched transcripts recovered and allowed us to assign most alleles as UAA. Allelic differences are primarily located in α1 and α2 domains in the residues known to interact with peptide in mammalian MHC class I, suggesting the diversity is functional. Most UAA alleles have unique residues in the cleft predicting distinct specificity; however, six alleles have an unusual conserved cleft with two cysteine residues. Residues that influence peptide-loading properties and tapasin involvement in chicken are fixed in duck alleles and suggest tapasin independence. Biased expression of one MHC class I gene may make viral escape within an individual easy, but high diversity in the population places continual pressure on the virus in the reservoir species.

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Section: Discussionmentioning

confidence: 85%

Section: Expressed Alleles Have Features Of Classical Mhc Class I H Cmentioning

confidence: 99%

Extensive Allelic Diversity of MHC Class I in Wild Mallard Ducks

Fleming-Canepa

Jensen

Mesa

et al. 2016

The Journal of Immunology

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“…Although class I and class II molecules have similar tertiary structures, they differ in the class of peptides that they bind and the proteolytic routes for processing them (Kaufman et al 1994;Castellino et al 1997;Gromme and Neefjes 2002). They also differ in the class of T cells that they react with (Housset and Malissen 2003).…”

Section: Mh Class I Versus Class Ii Patterns Of Variabilitymentioning

confidence: 99%

Patterns of variability at the major histocompatibility class II alpha locus in Atlantic salmon contrast with those at the class I locus

et al. 2005

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In order to investigate the mechanisms creating and maintaining variability at the major histocompatibility (MH) class II alpha (DAA) locus we examined patterns of polymorphism in two isolated Atlantic salmon populations which share a common post-glacial origin. As expected from their common origin, but contrary to the observation at the MH class I locus, these populations shared the majority of DAA alleles: out of 17 sequences observed, 11 were common to both populations. Recombination seems to play a more important role in the origin of new alleles at the class II alpha locus than at the class I locus. A greater than expected proportion of sites inferred to be positively selected (potentially peptide binding residues, PBRs) were found to be involved in recombination events, suggesting a mechanism for increasing MH variability through an interaction between recombination and natural selection. Thus it appears that although selection and recombination are important mechanisms for the evolution of both class II alpha and class I loci in the Atlantic salmon, the pattern of variability differs markedly between these classes of MH loci.

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“…Although the MHC-class I genes are present on the majority of cell types until now they have been poorly characterised. They code class I molecules which present antigenic peptides to CD8+ T cells (Kaufman et al, 1994;Dukkipati et al, 2006). Within Ovar-MHC class I locus have been found a few RFLP and polymorphic microsatellite sequences which differ among sheep breeds Charon et al, 2001;Gruszczyńska et al, 2002).…”

Section: Genetic Markers Within the Ovine Major Histocompatibility Comentioning

confidence: 99%