DNA polymorphism of HLA class II genes in systemic lupus erythematosus

Abstract: We investigated the DNA restriction fragment length polymorphism (RFLP) of the major histocompatibility complex (MHC) genes: HLA-DRB, -DQA, -DQB, -DPB in 24 Danish patients with systemic lupus erythematosus (SLE) and in 102 healthy Danes. A highly significant increase of the frequency of the DR3- and DRw6-associated 7.00 kb DRB Taq I DNA fragment was found in SLE patients compared to normal controls (83.3% vs 35.5%; RR = 9.1, p < 10^-4). The frequencies of the DQA1*0501-associated 4.56 kb DQA Taq I fragment and the DRB3*01/03-associated 9.79 kb Taq I fragment were also found to be significantly increased in SLE patients (70.8% vs 29.7%; RR = 5.8, p < 10^-2 for the DQA fragment and 70.8% vs 36.1%; RR = 4.3, p < 0.05 for the DRB3 fragment). Less extensive and insignificant increases of the frequencies of the DR3-associated DQB and DPB fragments were observed. The frequencies of the DR2-associated DRB, DQA, and DQB fragments were comparable to those found in normal controls.     

Major histocompatibility complex class II and C4 alleles in Mexican Americans with systemic lupus erythematosus

Abstract: Few data exist on associations of class II and class III alleles of the major histocompatibility complex (MHC) and susceptibility to systemic lupus erythematosus (SLE) in Mexican Americans, a group of predominantly mixed Spanish and Native American ancestry. Therefore, MHC class II alleles (HLA-DRB1, DQA1, DQB1, DPA1 and DPB1 alleles) and C4 allotypes were determined in 52 Mexican American SLE patients and 105 ethnic-matched controls. HLA-DRB1*0301 and C4A*Q0 were each increased in the SLE patients, especially HLA-DRB1*0301 in those with anti-Ro/SSA autoantibodies. C4A*Q0 was associated with HLA-DRB1*0301 only in a minority of patients and controls. Anti-U1-RNP antibodies were significantly associated with the presence of HLA-DQB1*0302, and the risk for the production of anti-Ro antibodies was heightened by the presence of at least three (out of four possible) DQA1 chains possessing a glutamine at position 34 and/or DQB1 chains a leucine at position 26 of their outermost domains. Thus the HLA class II and C4 null allele associations that have been noted in other ethnic groups are also found in Mexican Americans, suggesting shared susceptibility factors across ethnic lines in predisposition to SLE.     

Class II major histocompatibility antigens and the etiology of systemic lupus erythematosus

It is hypothesized that the underlying immunoregulatory dysfunction in systemic lupus erythematosus (SLE) is altered recognition by T cells of self class II major histocompatibility antigens (Ia). The resultant cellular autoreactivity would directly cause certain of the immunopathological manifestations of SLE. The perception by T cells of self non-MHC antigens in the context of altered Ia on antigen presenting cells would also stimulate specific help for autoantibody production. Autoimmunity induced by the graft-versus-host reaction is an experimental model that illustrates this potential mechanism (A. G. Rolink, S. T. Pals, and E. Gleichmann, J. Exp. Med. 157, 755, 1983; R. A. Eisenberg, S. Y. Craven, and P. L. Cohen, Arth. Rheum. 26, S19, 1983).     

Rabbit major histocompatibility complex. IV. Expression of major histocompatibility complex class II genes

The rabbit MHC class II DP, DQ, and DR alpha and beta chain genes were transfected into murine B lymphoma cells. The transfected cells expressed R-DQ and R-DR molecules on the cell surface but they did not express the R-DP genes either on the cell surface or at the level of mRNA. Northern blot analyses showed that the R-DP genes were expressed, albeit at low levels, in rabbit spleen. Similar analyses showed that the R-DQ and R-DR genes were expressed at high levels in rabbit spleen. A new monoclonal anti-rabbit class II antibody, RDR34, has been developed and shown to react with the R-DR transfected cells and not with the R-DQ transfected cells. The previously described monoclonal anti-rabbit class II antibody, 2C4, reacted with the R-DQ transfected cells and not with the R-DR transfected cells. Thus, 2C4 and RDR34 MAb's are specific for the R-DQ and R-DR molecules, respectively. Each of the antibodies reacted with approximately 50% of rabbit spleen cells as shown by immunofluorescent antibody studies.     

Rabbit major histocompatibility complex. III. Multiple class II DR beta genes and restriction fragment length polymorphism of the class II alpha and beta genes

Several class II alpha and beta chain genes of the rabbit MHC have been cloned and classified into three distinct subregions, R-DP, R-DQ and R-DR, based on their homology to the corresponding HLA-DP, -DQ and -DR genes. The organization of the rabbit MHC class II genes has now been studied in greater detail by analysing genomic DNA of an inbred III/J strain and several other RLA-D homozygous rabbits, with DNA probes derived from cloned R-DR beta genes. Eight previously cloned R-DR beta genes were shown to be allelic forms of five R-DR beta loci. Genomic blot analyses of DNA from seven rabbits homozygous for different RLA haplotypes revealed that the germline contains a total of approximately seven class II beta genes, one DQ beta, one DP beta and five DR beta. Extensive allelic polymorphism was identified by RFLP analysis using DQ and DR probes; limited RFLP was observed with DP probes. RFLP analyses allowed us to distinguish two haplotypes which had not been previously distinguished by MLR. Such RFLP analyses will be useful for identifying MHC 'compatible' rabbits for various immunobiological studies, including transplantation.     

Transfection of major histocompatibility complex class I and class II genes causes tumour rejection

Many human and mouse tumours do not express MHC class II antigens and have reduced levels of class I antigens. Because of the requirement for class I and/or class II antigen for antigen presentation to Th and Tc cells, these phenotypes may enable tumour cells to 'escape' the host's immune response. Experiments presented here are designed to assess the role of MHC class I and class II antigens in tumour immunity, and to overcome the MHC class I- or class II-negative phenotype. When transfected with the syngeneic H-2Db gene, the MHC antigen-negative 402AX teratocarcinoma expresses high levels of H-2Db antigen. 402AX/Db cells are rejected by MHC allogeneic and some MHC syngeneic 402AX-susceptible mice, however the fully syngeneic strain of origin (129) remains tumour-susceptible. Induction of MHC class I gene products on class I antigen-negative embryonal carcinoma cells therefore increases tumour immunogenicity in some hosts, but not in the fully syngeneic mouse. In an attempt to enhance antigen presentation of tumour-associated antigens to Th cells, MHC class I antigen-positive SaI (KkDd) sarcoma cells were transfected with syngeneic A alpha k and A beta k genes to generate Iak-expressing tumour cells. SaI/Ak cells are efficiently rejected by syngeneic A/J (KkDd) mice, while untransfected SaI cells are lethal. Induction of MHC class II antigen expression on the class I antigen-positive SaI sarcoma therefore completely abrogates malignancy.     

Enhanced major histocompatibility complex (MHC) class II antigen expression in lupus nephritis

Thirty-eight cases of lupus nephritis, all satisfying the American Rheumatism Association criteria for diagnosis of systemic lupus erythematosus (SLE), with renal involvement and biopsy were immunohistochemically studied for the expression of HLA-DR (DAKO: HLA-DR/alpha, TAL.1B5), one of the three known families belonging to the class II major histocompatibility complex (MHC), using a standard streptavidin-biotin-peroxidase method. 20 nephrectomies performed for renal trauma and tumours constituted the normal controls. Of the lupus nephritis cases, 34 were females and 4 males. Ethnically, 20 were Chinese, 13 Malay, 4 Indian and 1 of indigenous origin. Their ages ranged from 16 to 59 years (mean of 31 years). Histologically, 23 expressed World Health Organisation (WHO) class IV (diffuse proliferative), 10 WHO class V (diffuse membranous), 4 WHO class II (pure mesangiopathy) and 1 WHO class III (segmental and focal proliferative) nephritis. Activity scores ranged between 5 to 19 (mean = 8.6) and chronicity scored between 2 to 7 (mean = 3.2) on a standard scoring system. Similar to other studies, HLA-DR was expressed in the glomerular capillaries and peritubular capillaries of all and mesangium, tubules (proximal, distal and collecting), veins and arterioles of some normal controls. Interestingly, HLA-DR expression was noted in the arteries of 25% of the normal controls, a finding hitherto not reported. The frequency of lupus nephritis cases expressing HLA-DR in the various anatomical components did not differ significantly from the normal controls except that HLA-DR expression in arteries and arterioles was seen at a significantly increased frequency (p < 0.01) in lupus nephritis. This increased expression did not correlate with the WHO class, activity or chronicity scores. It therefore appears that MHC class II shows increased expression in the arterial system of lupus nephritis kidneys. The significance of this is unclear but could be related to heightened (gamma-interferon activation which may be a de novo phenomenon or result of T cell proliferation and activation in SLE.     

Family study of the major histocompatibility complex in HLA DR3 negative patients with systemic lupus erythematosus

Susceptibility to systemic lupus erythematosus (SLE) is known to be governed by genes in the HLA region of the 6th chromosome. From previous studies it has not been possible to distinguish between the effects of null genes for the complement component C4 and HLA-DR3, because of the marked linkage disequilibrium between DR3 and a null allele of C4A (C4A QO) in caucasoid populations. We report here an immunogenetic study of 44 cases of SLE, selected because they were DR3 negative. Eighteen of the 30 Caucasoid cases (60%) had extended HLA haplotypes with a C4 null allele, compared with 22 of 60 (37%) of a control panel of 60 DR3 negative normal Caucasoid subjects. This difference is significant (chi 2 = 4.41; 0.05 greater than P greater than 0.01). Of 14 non-caucasoid patients analysed, 10 had a C4 null allele. It is concluded that the null alleles of the C4 A and B genes are themselves directly responsible for conferring susceptibility to SLE.     

Distribution and origin of bovine major histocompatibility complex class II DQA1 genes in Japan

We sequenced the major histocompatibility complex (MHC) class II DQA1 gene in 352 Japanese cattle (95 Japanese Black, 91 Holstein, 102 Japanese Shorthorn and 64 Jersey cattle) using a new sequence-based typing method. In total, 19 bovine MHC ( BoLA )- DQA1 alleles, of which two were novel alleles, were detected. The Holstein, Jersey, Japanese Shorthorn and Japanese Black breeds had 13, 12, 10 and 15 alleles, respectively. The dendrogram that was constructed by the neighbor-joining method on the basis of the DQA1 gene allele frequencies of the four Japanese cattle breeds showed that the Holstein and Japanese Black breeds were closest to each other, with Jersey being farther from these two breeds than Japanese Shorthorn. In addition, Wu–Kabat analysis showed that the DQA1 alleles of the Holstein and Japanese Black were the most and least polymorphic, respectively. Phylogenetic analyses indicated that the DQA1 gene of Bovidae such as cattle, sheep, bison and goat were more similar to pig SLA-DQA genes than to human HLA-DQA1 and dog DLA-DQA genes. The cattle, goat, bison, sheep, human and pig DQA1 molecules had similar rates of amino acid sequence polymorphism, but the distribution of their polymorphic residues differed from that in the dog DQA1 protein. However, the Bovidae DQA1 molecule had more polymorphic residues than the human, pig and dog DQA molecules at two regions, namely positions 52–53 and 65–66. This indicates that the Bovidae DQA1 locus is more polymorphic than the DQA loci of other species.     

Expressed major histocompatibility complex class II loci in fishes

Summary: Peptides derived from parasites are presented to T helper cells by major histocompatibility complex (MHC) class II αβ heterotrimeric cell-surface molecules. In mice and humans, the genes encoding these antigen-presenting molecules are known to be polymorphic and poly-genic. Multiple loci for MHC class II A and E genes are proposed to allow for an increased peptide-binding repertoire. The multigenic nature of expressed MHC class II loci and the differences between these loci in fishes are the focus of this review, Particular emphasis is placed on an evolutionary comparison of class II B loci, especially two class 11 B loci that have undergone dramatic changes from one another suggesting an ancestral gene duplication event that took place at an early stage in the evolution of teleosts, The number of functional class II αβ loci heterotrimers may have a profound impact on the organisms ability to battle constantly evolving parasitic infections.     

Interferon-induced expression of class II major histocompatibility antigens in the major histocompatibility complex (MHC) class II deficiency syndrome

Class II antigens encoded by genes of the major histocompatibility complex (MHC) are expressed by a variety of cell types and have a vital role in the cellular interactions required for an effective immune response. We have analyzed the regulation of HLA-DR, DP, and DQ class II antigen expression on cells of different lineage from an immunodeficient patient with the MHC class II deficiency syndrome. T and B lymphocytes, monocytes, and fibroblasts, which initially expressed no class II antigens, were treated with inductive stimuli that normally lead to enhanced expression of class II antigens. Monocytes, but not fibroblasts, cultured for 48–96 hr in the presence of recombinant gamma interferon expressed all three types of class II antigens. In contrast, T lymphocytes did not express class II antigens following their exposure to a variety of stimuli, including activation with phytohemagglutinin and culture in the presence of interleukin-2, transformation by the retrovirus HTLV-1 or HTLV-2, or exposure to the demethylating agent 5-azacytidine. Similarly, class II antigens were not induced on B cells by cross-linkage of surface immunoglobulin molecules with anti-mu, exposure to Epstein-Barr virus, or treatment with soluble factors secreted by activated T cells. These results demonstrate that the regulation of class II MHC antigen expression by monocytes and lymphocytes is dissimilar and suggest that different regulatory genes are involved in the control of class II antigen expression by cells of different lineage.     

HLA class II haplotypes in Mexican systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is an autoimmune disease in which polymorphisms within the human leukocyte antigen (HLA) region have been associated to its etiology. For this study, HLA-DQB1, DQA1, and DRB1 genes were typed by polymerase chain reaction–sequence-specific primer in 237 individuals, taken from 74 families, who had a member with SLE, and who had their residence in the western region of Mexico; as well as in 159 ethnically matched healthy volunteers taken from 32 families. Genotype and allele frequency analysis was performed in 74 SLE patients and 54 unrelated controls. Precise three-loci identification of independent haplotypes was performed in 48 patients and 54 controls by familial segregation. Genotype distribution at each loci was concordant with Hardy-Weinberg’s equilibrium in the control group. In general, no genotype effect was observed in SLE patients. Allele distribution comparison showed in the SLE group a significant increase of HLA-DQA1*0102, DQB1*0402, and DRB1*15; whereas alleles HLA-DQB1*0303 and *0501 were significantly decreased. SLE patients showed haplotype DQB1*0602-DQA1-*0102-DRB1*15 increased. As expected, patients with SLE have a reduced haplotype genetic diversity. The associations found in this study are related to an ancestral haplotype that has been observed in SLE populations of different origins.     

Duplicated major histocompatibility complex class II genes in the tongue sole (Cynoglossus semilaevis)

The major histocompatibility complex (MHC) molecule plays an important role in the vertebrate immune system. However, we have a limited understanding of the MHC genomic structure in teleosts. Using gene cloning and family analysis, we isolate the MHC class II genes in the tongue sole (Cynoglossus semilaevis) and find that both class II A and class II B genes are duplicated (named Cyse‐DAA and Cyse‐DBA, Cyse‐DAB and Cyse‐DBB, respectively). The class II A genes consist of four exons with a highly conserved genomic structure, but each gene has unique and defining exon 2 and intron 2 sequences. The class II B genes have a conserved six‐exon genomic structure, with intron 3 splitting the β2 encoding region into two exons. Each class II B gene has unique variations in exon 2 and intron 1 sequences. The two class II A genes have similar expression patterns among tissues, with high levels in spleen and gill. Both class II B genes have similar patterns, with high expression in spleen, gill and intestine. The alleles of MHC class II have wide distribution and reliable inheritance in the families analysed. This indicates that the duplicated MHC genes are all classical class II genes. The class II gene duplication with divergent exon and intron sequences, but similar expression patterns in tongue sole provides new insights into MHC evolution.     

Systemic lupus erythematosus in dogs: association to the major histocompatibility complex class I antigen DLA-A7.

The DLA-A,B antigens and the allotypes of the fourth complement component have been determined in German shepherd dogs suffering from systemic lupus erythematosus. We have typed 26 unrelated affected dogs, 11 animals of a three generation family, and 16 dogs of a colony with a high frequency of the disease. The results obtained from the 26 unrelated diseased dogs were compared to those determined in the 23 unaffected German shepherds. The antigen DLA-A7 was found to be predominant in the diseased group with a c2 = 11.02, Pc = 0.02, and a relative risk for the carriers of 11.93. The antigens DLA-A1 and DLA-B5 were negatively associated to the disease (c2 = 14.95, Pc = 0.001, and c2 = 17.16, P = 0.0008 respectively) and thus may be of protective nature. These data were further substantiated by the typing of the three generation family and the colony.     

Molecular analysis of the genes for human class II antigens of the major histocompatibility complex

Different cDNA clones have been isolated that encode each of the three chains of HLA-DR antigens: alpha, intermediate and beta, as well as another beta chain, most likely DC. Whereas the DR alpha and intermediate chains seem encoded by single genes, the DR and DC beta chains are most likely encoded by multiple genes; furthermore, their polymorphism can be readily detected by restriction analysis of cellular DNA. Several genomic DNA clones were isolated for the DR and DC beta chain genes and for the intermediate chain gene. The sum of all distinct cDNA clones and genomic DNA clones for HLA-DR beta chains, isolated from a heterozygous cell line, represent five genes. This implies the existence of at least three nonallelic DR beta chain genes in addition to the DC beta chain genes. The complete sequence of one of the DR beta chains is presented. A genomic DNA clone for a DR beta chain was transferred into mouse L cells and found to be expressed into RNA of the same size as DR beta mRNA. The finding, among the genes for class II antigens, of multiple genes for the beta chain of HLA-DR, distinct from those of other known subregions such as DC, emphasizes the importance of gene transfer experiments, where individual genes can be expressed and tested for their functional role in the immune response.