Correlations between polymorphisms at the DNA and at the protein level of DRw52 haplotypes, revealed with a variety of techniques

Distribution of Polymorphic HLA-DR and -DQ Alleles as Determined by Restriction Fragment Length Polymorphism Analysis in an Austrian Population

The restriction fragment length polymorphism (RFLP) of HLA-DR beta, -DQ alpha and -DQ beta genes was analyzed in 637 unrelated individuals from the Austrian population. The restriction enzyme was Taq I, and three exon-specific probes were applied. The gene frequencies, the Hardy-Weinberg equilibrium in DR beta and DQ loci, linkage disequilibria between the loci and haplotype frequencies are calculated. Rare associations between DR and DQ loci are described. Two RFLP patterns are demonstrated which were unique in the overall 1,000 individuals tested so far.

Trans-species evolution of Mhc-DRB haplotype polymorphism in primates: organization of DRB genes in the chimpanzee

The DRB region of the human major histocompatibility complex displays length polymorphism: Five major haplotypes differing in the number and type of genes they contain have been identified, each at appreciable frequency. In an attempt to determine whether this haplotype polymorphism, like the allelic polymorphism, predates the divergence of humans from great apes, we have worked out the organization of the DRB region of the chimpanzee Hugo using a combination of chromosome walking, pulsed-field gel electrophoresis, and sequencing. Hugo is a DRB homozygote whose single DRB haplotype is some 440 kilobases (kb) long and contains five genes. At least one and possibly two of these are pseudogenes, while three are presumably active genes. The genes are designated DRB*A0201, DRB2*0101, DRB3*0201, DRB6*0105, and DRB5*0301, and are arranged in this order on the chromosome. The DRB2 and DRB3 genes are separated by approximately 250 kb of sequence that does not seem to contain any additional DRB genes. The DRB*A0201 gene is related to the DRB1 gene of the human DR2 haplotype; the DRB2*0101 and DRB3*0201 genes are related to the DRB2 and DRB3 genes of the human DR3 haplotype, respectively; the DRB6*0105 and DRB5*0301 genes are related to the DRBVI and DRB5 genes of the human DR2 haplotype, respectively. Thus the Hugo haplotype appears to correspond to the entire human DR2 haplotype, into which a region representing a portion of the human DR3 haplotype has been inserted. Since other chimpanzees have their DRB regions organized in different ways, we conclude that, first, the chimpanzee DRB region, like the human DRB region, displays length polymorphism; second, some chimpanzee DRB haplotypes are longer than the longest known human DRB haplotypes; third, in some chimpanzee haplotypes at least, the DRB genes occur in combinations different from those of the human haplotypes; fourth, and most importantly, certain DRB gene combinations have been conserved in the evolution of chimpanzees and humans from their common ancestors. These data thus provide evidence that not only allelic but also haplotype polymorphism can be passed on from one species to another in a given evolutionary lineage.

Association between IgE response against Bet v I, the major allergen of Birch Pollen, and HLA-DRB alleles

The association of the human IgE response against Bet v I, the major allergen of birch pollen, and the HLA-DR and DQ phenotype was studied. Birch pollen allergic patients showed a typical case history, positive skin-prick test, and positive RAST with birch pollen extracts. They were divided into two groups. Group I (n = 37) consisted of individuals generating IgE antibodies that selectively reacted with Bet v I. Their serum IgE did not react with minor allergens from birch pollen as tested by immunoblot analysis, nor did they show a response against allergens from a panel of grass and other tree pollen or perennial allergens from animals and fungi as determined by skin-prick test. Patients belonging to group II (n = 34) possessed IgE reacting with Bet v I plus one or more additional allergens. The control group consisted of 637 healthy blood donors. Comparison of the frequencies of RFLP-defined HLA-DR and DQ alleles in patients and the control group revealed that the distribution of DRB3 alleles in group I patients differed significantly from that in the control group: A higher frequency of the DRw52a/c alleles in comparison to the control group (pcorr less than 0.02) was observed. In addition, alleles defined by nucleotide sequences coding for the amino acid sequence tyrosine-phenylalanine-histidine at positions 30-32 of the beta chain of DR molecules were found with a higher frequency in patient group I (pcorr less than 0.02), too. These alleles comprise DRw52a/c and some DRB1 alleles.(ABSTRACT TRUNCATED AT 250 WORDS)

Linkage mapping of human polymorphic proteins identified by two-dimensional electrophoresis

Nineteen polymorphic lymphocyte proteins were previously detected by two-dimensional protein electrophoresis (2DE). In this report, we describe the genetic linkage mapping of six of these polymorphic proteins (PNIA1-PNIA6), the identification by genetic linkage of a seventh (glyoxalase 1 on 6p21), and support for the mapping of an eighth (plastin or LCP1) to near the ESD locus on Chr 13. PNIA1-PNIA6 were assigned, respectively, to 10q26, 16p13.3, 10q, 11p15, 3q, and 19q13. These genetic linkages were achieved by classical linkage analysis of 2DE protein charge polymorphisms to the panel of RFLPs previously typed in nine pedigrees in the Centre D'Etude du Polymorphisme Humain (CEPH) collection.

RFLP analysis of HLA-DR5 haplotypes

The analysis of HLA-DR5 haplotypes unravelled a new DRB3 polymorphism and permitted the identification of various associations between alleles of the DRB1 and DRB3 loci. This new polymorphism consists of a 10.5 kb Taq1 restriction fragment which was encountered in an African-American family (JS). In Caucasoids, the DRw11 allele has been previously observed only in association with the DRw52b allele. RFLP and oligonucleotide typing of HLA-DRw52 alleles associated with DRw11 showed, however, that 4 Caucasoid individuals from our panel carried the DRw52a allele and 1 the DRw52c allele. Similarly, DRw12, which is usually associated with DRw52b, was encountered with DRw52a in 1 Chinese and with DRw52c in an African-American and a Chinese panel member. The study of DRB3 alleles associated with DRw11 and DRw12 indicates that, similar to serology, RFLP studies become particularly informative when individuals of different races and ethnic origins are studied.

Implication of the HLA-DRB3 gene in Graves' disease: predominance of allele Dw24

Using RFLP, the present study sets off to determine the MHC class II gene polymorphism in Graves' disease, in order to define the HLA-related genetic susceptibility. Considering the preferential link between Graves' disease and the HLA-DR3 antigen, 42 HLA-DR3 Graves' disease patients were studied and compared with 42 HLA-DR-matched controls. Hybridization with a DQ alpha probe of DNAs digested by Taq I revealed a polymorphism of the DR3 haplotype with an overrepresentation of a 2.1 kb(U) fragment in patients, but this was merely a sign of the linkage disequilibrium between U and B8DR3. Hybridization with the DR beta probe of DNAs digested by Taq I yielded more facts. It revealed the overrepresentation of the Dw24 specificity (Taq I:9.8 kb) in DR3 Graves' disease patients. This study thus enabled us to determine precisely the susceptibility linked to the DR3 haplotype, implicating the DRB3 gene and its Dw24 allele, which appear to be the most reliable markers of the disease, providing a higher relative risk than B8DR3.

CD4+ cytolytic T cell clones that recognize polymorphism of HLA-DR beta 3 chains

We have investigated HLA-DR beta 3-associated functional polymorphism using selected Epstein-Barr virus (EBV) specific human T cell clones and EBV-transformed B cell (EBV-B) lines. To study the relationship between T cell recognition and the gene products of the three alleles of the DR beta 3 locus, Dw24, 25 and 26 (these were previously called DRw52a, b and c, respectively), CD4+ cytolytic T cell clones (CD4+ CTL) were isolated by repeated stimulation of peripheral blood mononuclear cells (HLA A2 A24; B8 B27; DRw17, Dw24, DRw2) with autologous EBV-B. Clone no. 32 proliferated strongly in response to HLA-Dw24 EBV-B, but not to Dw25 or Dw26 EBV-B. Furthermore, clones no. 32 and no. 45 both lysed HLA-Dw24 EBV-B but not Dw25 or Dw26 EBV-B. In addition, cold target inhibition studies showed that the cytolytic activity of both clones was blocked by unlabelled HLA-Dw24 EBV-B, but not by Dw25 or Dw26 EBV-B. Clones no. 32 and no. 45, therefore, could distinguish between the three allelic products of DR beta 3 haplotypes.

Polymorphism of DRw52 and its association with DRw11 and DRw12 in South African blacks (Negroes) and individuals of mixed ancestry (Cape coloreds)

The HLA-DRB3 gene, which encodes the supertypic HLA-DRw52 antigen, has been shown to have limited polymorphism. The alleles at this locus are also in linkage disequilibrium with the alleles at the DRB1 locus. We have studied 16 DRw11 and three DRw12 haplotypes in the South African populations. Five of the DRw11,DQw7 haplotypes were associated with a TaqI restriction fragment length polymorphism which has not been previously described and which correlated with the DRB3 gene. This new variant, which has been called DRw52d, is confined to individuals of black or mixed ancestry. Two of the DRw11,DQw7 haplotypes were also associated with DRw52a or DRw52c and not with DRw52b as has always been observed in white populations. The less common DRw11,DQw6 haplotype, observed in four individuals, also revealed different allelic associations with the DRB3 gene, together with an unusual DQA association. None of the three DRw12,DQw7 haplotypes had the usual association with the DRw52b allele and also demonstrated two distinct DQA associations. The pattern of linkage disequilibrium of the HLA-D region loci in the South African black populations is more complex than in other populations. These findings may be of significance for the matching of unrelated donors for organ transplantation, as well as the study of disease association with HLA.

Different HLA DR-DQ associations in subgroups of idiopathic myasthenia gravis

We have investigated the HLA-DRB and -DQB gene polymorphism in 131 myasthenia gravis (MG) patients. The HLA genotypes in these patients were assigned by means of restriction fragment length polymorphism (RFLP)-defined DR-DQ haplotypes, correlating to serologic HLA class II typing. Using this technique we could, among randomly selected non-thymomatous (NT)-MG patients, confirm the strong association to DR3, and 70% of the patients were found to carry a specific DR3-positive DR-DQ haplotype, T-3.1. Furthermore, an analysis of T-3.1- NT-MG patients revealed that 59% were T-4.1+ (DR4, DQw8). Thymic hyperplasia was found in approximately 85% of the T-3.1+, as well as of the T-4.1+/3.1- patients. As previously observed, we found a clear dominance of females among the T-3.1+ NT-MG patients. However, among T-4.1+/3.1- patients, males were as common as females. Furthermore, the T-4.1+ patients were significantly older at the onset of disease than those who were T-3.1+. In female MG patients, the DRw15-Dw2-positive haplotype T-2.1 was strongly correlated with the presence of thymoma (T-MG). These data indicate that the HLA associations in early vs late onset of NT-MG are different, and that female patients with and without thymoma differ from each other with regard to HLA markers. Thus, at least three different HLA DR-DQ associations are found in subgroups of idiopathic MG.

Restriction fragment length polymorphism of HLA-DRw53 detected in South African blacks and individuals of mixed ancestry

The HLA-DRw53 specificity has not until now been shown to demonstrate polymorphism. We have studied 33 DRw53 haplotypes, comprising 19 DR4, 10 DR7, and 4 DR9 haplotypes, from 6 homozygous typing cells, 11 families, and 8 random individuals. All the subjects studied were South African blacks or of mixed ancestry (Cape Coloureds), with the exception of four homozygous typing cells from whites. The DNA was digested with TaqI and, after Southern blotting, was hybridized with a full-length DRB cDNA probe. Fragments correlating with DR4 (5.5 kb), DR7 (4.0 kb), and DR9 (4.1 kb) were observed. Two fragments of 14.5 and 2.8 kb correlated with DRw53. In addition, two pairs of fragments demonstrated a diallelic pattern, which is likely to correlate with a polymorphism of the DRB4 (DRw53) gene, since one or other of the two patterns was observed in all cells carrying the DRw53 specificity. The first allelic pattern, called DRw53a, was characterized by the presence of 7.5- and 2.6-kb fragments, while the second pattern, called DRw53b, had 5.8- and 2.7-kb fragments. DRw53a occurred in 10 of the 19 DR4 haplotypes and 7 of the 10 DR7 haplotypes. All three DR9,DQw2 haplotypes were also associated with DRw53a. These findings may have important implications for disease associations and the use of unrelated donors for organ transplantation.

A novel T-cell-defined HLA-DR polymorphism not predicted from the linear amino acid sequence

Recent investigations have shown that alloreactive T cells are capable of responding to structures defined by specific linear amino acid sequences on class II molecules. In the present study we show that also a polymorphism can be recognized that is not defined by such linear amino acid sequences. Two human T-cell clones, sensitized to DRw13 haplotypes, are described. The description of clone c50 serves to exemplify the first model. This DRB1-specific clone responds to stimulator cells that carry DR molecules, different in their DRB1 first and second hypervariable regions (HV1 and HV2) but identical in their HV3 regions (i.e., DRw13,Dw18; DRw13,Dw19; DR4,Dw10; and DRw11,LDVII). The second clone, c1443, behaves nonconventionally. It responds to DRw13,Dw18; DRw13,Dw19; and DR4,Dw4 stimulator cells, although no specific amino acid sequence is shared between these specificities. The latter pattern of reactivity suggests the existence of a novel polymorphism recognized by alloreactive T cells. This particular polymorphism may also be biologically significant.

Correlation of structure with T cell responses of the three members of the HLA-DRw52 allelic series

A third allele at the DRB3 locus, DRw52c, represents an intermediate sequence between DRw52a and DRw52b and may have arisen by a gene conversion-like event. The recognition of cells bearing these molecules by a number of alloreactive and antigen-specific DR-restricted T cell clones was analyzed. On the basis of a theoretical model of HLA class II structure, distinct amino acid clusters have been identified as motifs controlling TCR recognition. These are located both in the cleft and in the alpha-helical edge of the MHC class II recognition platform. Motifs shared between two alleles may restrict public T cell clones.

DNA typing of an HLA-DR bilocus specificity by gene amplification and oligonucleotide hybridization

The structure of the DRB1*03 gene has been interpreted as the product of a gene conversion event involving a DRB3 gene as donor and resulting in the introduction of two short segments of the DRB3 sequence into the DRB1 locus. The serological counterpart of this double insertion is the TR81 specificity. Consequently, the TR81-specifying sequences can reside on either DRB1 or DRB3, or on both loci. Within each of the two sequence stretches a single nucleotide may be responsible for the generation of the TR81 alloantigen. Oligonucleotide probes corresponding to these stretches and to their allelic variants were constructed. They were used, under stringent hybridization conditions, to detect TR81-specifying sequences in the DNA of HLA-homozygous cell lines carrying different haplotypes of the DRw52 family. Prior to hybridization the DNA was amplified with either DRB1-specific or DRB3-specific primers. Using this approach it was possible to perform a "DNA typing" of the TR81-specifying sites separately on both the DRB1 locus and the DRB3 locus.

HLA-DR beta III and HLA-DP induce comparable proliferation in primary mixed lymphocyte culture

To study the stimulatory capacity of HLA-DR beta III in the mixed lymphocyte culture (MLC) assay, an MLC matrix between 13 Dw18 homozygous typing cells (HTCs) was analysed. Six of these HTCs were positive for the HLA-DR beta III allele LB-Q1 as defined by T cell clones. Seven HTCs were positive for LB-Q4. The MLC responses between Dw18 HTCs, matched for LB-Q, were significantly lower than the responses between the mismatched combinations. Considering the fact that HLA-DP can induce proliferation in MLC, we then analysed the DP matched and mismatched combinations separately. The influence of HLA-DR beta III mismatches was in our experiments comparable to the influence of mismatches for HLA-DP. Surprisingly, 15 out of 22 DR beta III and DP matched combinations still showed positive MLC reactions.