Polymorphism of Bovine MHC Class Ii Genes. Joint Report of the Fifth International Bovine Lymphocyte Antigen (Bola) Workshop, Interlaken, Switzerland, 1 August 1992

Abstract

Polymorphism of the bovine DRB, DQA, DQB, DYA, DOB and DIB genes was investigated using restriction fragment length polymorphism (RFLP) analysis, isoelectric focusing (IEF), class II serology and polymerase chain reaction (PCR) based typing techniques. The simultaneous application of multiple typing techniques and the characterization of multiple genes resulted in a greatly enhanced picture of the bovine class II regions. Thirty-eight class IIa (DR-DQ) and 5 class IIb (DYA-DOB-DIB) haplotypes were defined. It was found that IEF types were associated with DRB3 polymorphism defined by DRB3 PCR-RFLP and DRB3 microsatellite PCR. Serologically defined polymorphism was associated with distinct molecular/IEF motifs and, therefore, DR and DQ specificities could be tentatively distinguished. Although the DR and DQ genes are tightly linked, neither DR nor DQ typing defined all of the class IIa region polymorphism. Furthermore, even the most powerful DRB3 typing technique, DRB3 PCR-RFLP, failed to detect all expressed DRB3 polymorphism. All detected DRB3 polymorphism could, however, be distinguished with a combination of two molecular techniques: DRB3 PCR-RFLP and DRB3 microsatellite PCR. RFLP typing with transmembrane probes detected significantly less polymorphism than typing with cDNA or exon probes. However, the transmembrane probes were useful because they were locus specific. The presence of only 5 of 12 possible class IIb haplotypes was unexpected and indicates that the DYA, DOB and DIB genes are tightly linked.

Duplicated DQ Haplotypes Increase the Complexity of Restriction Element Usage in Cattle

“…28). In most cases, the PCR-RFLP typing data were consistent with conserved haplotypes characterized in the BoLA workshop (28), except that the two DRB3.2*11 APC (Table II, APC 5 and 10) had different associated DQA PCR-RFLP patterns, suggesting that they had distinct haplotypes.…”

“…The DQ molecules associated with the haplotypes DH24A (and DH15B) and DH28A are likely to be structurally and functionally similar. These haplotypes share both a serological specificity, Dw3 (28), and an allo-T cell specificity (42), yet all have different DR molecules (28). In addition, the DQB*0103 allele, associated with DH28A by RFLP typing data (28), differs from the DH24A DQB*0101 allele by only four conservative substitutions in the Ag-binding cleft (Y30-H, F61-W, F67-I, and Q70-R) (43).…”

“…These haplotypes share both a serological specificity, Dw3 (28), and an allo-T cell specificity (42), yet all have different DR molecules (28). In addition, the DQB*0103 allele, associated with DH28A by RFLP typing data (28), differs from the DH24A DQB*0101 allele by only four conservative substitutions in the Ag-binding cleft (Y30-H, F61-W, F67-I, and Q70-R) (43). Thus, the DQ molecules of DH24A/DH15B and DH28A may belong to a class II supertype (44), sharing structural similarities that are reflected in both their peptide and TCR specificity.…”

“…28; see Table I), and the sequences of DRA, DRB3, DQA, and DQB alleles from the immunized animals have been determined (see Table II; Refs. 23-25; our unpublished data).…”

The Major Histocompatibility Complex in Bovines: A Review

“…The class II region has been characterized using serological techniques [32], cloned heterologous and homologous class II probes [33], RFLP [34, 35], PCR-RFLP [36], and by gene sequencing [37]. Enormous information on the molecular features of the BoLA class II genes can be found in the 8th report of the International Society of Animal Genetics BoLA Nomenclature Committee [25, 26] and on the BoLA website (http://www.ebi.ac.uk/cgi-bin/ipd/mhc/view_nomenclature.cgi?bola.drb3).…”