Extensive interbreed, but minimal intrabreed, variation of DLA class II alleles and haplotypes in dogs

Abstract

The DLA class II genes in the dog major histocompatibility complex are highly polymorphic. To date, 52 DLA-DRB1, 16 DLA-DQA1 and 41 DLA-DQB1 allelic sequences have been assigned. The aim of this study was to examine the intrabreed and interbreed variation of DLA allele and haplotype frequencies in dogs, and to ascertain whether conserved DLA class II haplotypes occur within and between different breeds. One thousand and 25 DNA samples from over 80 different breeds were DLA class II genotyped, the number of dogs per breed ranging from 1 to 61. DNA sequence based typing and sequence specific oligonucleotide probing were used to characterize dogs for their DLA-DRB1, DQA1 and DQB1 alleles. The high frequency of DLA class II homozygous animals (35%), allowed the assignment of many haplotypes despite the absence of family data. Four new DLA alleles were identified during the course of this study. Analysis of the data revealed considerable interbreed variation, not only in allele frequency, but also in the numbers of alleles found per breed. There was also considerable variation in the number of breeds in which particular alleles were found. These interbreed variations were found in all three DLA class II loci tested, and also applied to the three-locus haplotypes identified. Within this data set, 58 different DLA-DRB1/DQA1/DQB1 three-locus haplotypes were identified, which were all found in at least two different animals. Some of the haplotypes appeared to be characteristic of certain breeds. The high interbreed, and relatively low intrabreed, variation of MHC alleles and haplotypes found in this study could provide an explanation for reports of interbreed variation of immune responses to vaccines, viruses and other infections.

Stable long-term mixed chimerism achieved in a canine model of allogeneic in utero hematopoietic cell transplantation

“…4 We did not perform preemptive DLA testing on breeding pairs. 11 However, based on review of 5-generation pedigrees, pups have no shared ancestors at 4 generations removed, with 2 sharing 1 at the fifth generation. Twenty-nine fetuses of 6 pregnant dogs underwent IC injection at GA39-42.5 (Table 1).…”

Diversity of Antibody Responses to Borrelia burgdorferi in Experimentally Infected Beagle Dogs

“…If the immunization protocol were insufficient to elicit detectable specific antibody responses, then it is unlikely that an unspecified effect of this lipoprotein would have lasted for so many months. Although the major histocompatibility complex (MHC) class I and II genotypes of the dogs in the study are not known, it is likely that, in comparison with the population of all dog breeds, there were relatively few MHC haplotypes represented among the beagles (46). This means that the range of potential antibody responses might have been restricted but also that the differences in traits that were observed may eventually be more feasibly associated with a genetic locus in beagles than would be the case for a population with a different demographic history, a larger effective size, and less linkage disequilibrium (34).…”

Oral Administration of β-1,3/1,6-Glucan to Dogs Temporally Changes Total and Antigen-Specific IgA and IgM

“…To diminish variation, samples were taken each day at the same hour (13). Furthermore, both experiments were performed with animals of the same breed (17). The oral administration of MacroGard increased the serum IgM concentration and decreased the serum and mucosal IgA concentrations, whereas no effect on IgG concentrations was seen, suggesting that the effect of the ␤-glucan was induced at the intestinal mucosa.…”