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At least 217 records · Page 12Linked to original sources
PubMed1998

Variable number of pig MHC class I genes in different serologically defined haplotypes identified by a 3'-untranslated region probe.

To estimate the number of porcine class I major histocompatibility genes, a short class I cDNA probe from the 3'-untranslated region was developed to be used in restriction fragment length polymorphism analysis. Six clones isolated from a pig spleen cDNA library were sequenced from their 3'-untranslated region. Three different transcripts were identified, one probably derived from the class I PD7 locus and two showing highest homology to the PD1 and the PD14 genes, respectively. Class I typing was performed both by restriction fragment length polymorphism and serology. Segregation of class I haplotypes was followed in one three-generation family (European Wild Boar x Large White: Swedish Yorkshire) and in six two-generation families (Duroc, Yorkshire and Chester White), for a total of 266 pigs. Twenty different class I haplotypes were identified either with restriction fragment length polymorphism and/or serological typing. Furthermore, previously unpublished serological haplotypes H62, H67 and H68 were identified. Two to seven polymorphic and three monomorphic fragments were detected in different restriction fragment length polymorphism haplotypes indicating that the number of class I genes in the investigated haplotypes varies.

Animals↗
PubMed2001

Species-specific evolution of MHC class I genes in the higher primates.

Humans express three highly polymorphic 'classical' (HLA-A,B and C) and three conserved 'non-classical' (HLA-E, F and G) MHC class I genes. Their comparison with the MHC class I genes of apes and monkeys reveals the differential extent to which MHC class I genes have been preserved during primate evolution. African apes have orthologues of all six human genes, and although allelic lineages of the A and C loci are shared, these species share none of the human alleles. In Asian apes, several MHC class I genes show significant differences from the human genes, a trend which continues with the Old World monkeys, and even more so in the New World monkeys, where E and F are the only human gene orthologues. The C locus is confined to humans and apes. Multiple A-related and B-related loci have been identified in apes and Old World monkeys showing that duplication of these loci has been a common event during primate evolution. Certain of the daughter loci exhibit low polymorphism, suggesting they have adopted a non-classical function. The differing rates at which MHC class I genes have evolved during primate evolution likely reflects their differing functions in the immune response.

Animals↗
PubMed1991

Hetero- and homozygosity of MHC class II gene products in systemic lupus erythematosus. The Members of the Deutsche Multizentrische SLE-Studie.

An analysis of HLA class II antigens in 356 white patients with systemic lupus erythematosus (SLE) showed that all HLA-DR and -DQ homozygous and heterozygous combinations appear with frequencies expected from the observed gene frequencies. HLA-DR2 and HLA-DR3 gene frequencies were both increased in SLE, as were the odds ratios of all DR2 and DR3 hetero- and homozygous combinations. HLA-DR2/C4AQ0 heterozygotes were also not increased over expected values. Therefore, gene complementation at MHC loci does not contribute to susceptibility to SLE, but rather one or two MHC allele(s) in linkage with HLA-DR2 and HLA-DR3.

Alleles↗
PubMed2003

MHC class II genes in HCV viral clearance of hepatitis C infected Hispanic patients.

The frequency of class II human leukocyte antigen (HLA) alleles in 112 infected patients of Hispanic ancestry with serology positive for hepatitis C virus (HCV) was investigated. Our studies failed to demonstrate significant association between class II HLA alleles and the outcome of HCV infection: chronic viremia versus spontaneous viral clearance. Our results suggest that the genes responsible for the outcome are unknown, so far, and those HLA associations reported in several ethnic groups may represent genetic markers in nonrandom association with the responsible genes involved in determining viral clearance or chronic viremia following HCV infection.

Adult↗
PubMed1993

Two factors, IRF1 and KBF1/NF-kappa B, cooperate during induction of MHC class I gene expression by interferon alpha beta or Newcastle disease virus.

The expression of class I genes of the Major Histocompatibility Complex is stimulated by IFN. The promoter of these genes contains an interferon response sequence (IRS) which overlaps the major enhancer. These elements are recognized by several protein factors, including IRF-1, which binds the IRS, and KBF1/NF-kappa B, which binds the enhancer. We demonstrate here that infection by Newcastle Disease Virus (NDV) results in an increased expression of class I genes, by a mechanism partially different from that of IFN, but that in both cases the cooperative action of IRF1 and KBF1/NF-kappa B is required. In F9 embryonal carcinoma cells, where KBF1/NF-kappa B activity cannot be detected, both types of stimuli are ineffective.

Animals↗
PubMed1998

[The role of MHC class II genes in the etiopathogenesis of rheumatoid arthritis].

Rheumatoid arthritis (RA) is associated with HLA-DR4 and DR1 antigens. HLA-DRB1 gene sequences analysis demonstrated that only a limited set of alleles is positively associated with RA. Third hypervariable region sequences (70-74, 86) Q(R)R(K)RAA, G(V) are found in up to 95% of erosive RA. The presence of disease-associated allels may predict severe outcome of the disease. Therefore, their presence may allow us to start aggressive therapy in early stage of the disease.

Arthritis, Rheumatoid↗
PubMed1985

Tissue-specific, inducible and functional expression of the E alpha d MHC class II gene in transgenic mice.

We have introduced the class II E alpha d gene into (C57BL/6 X SJL) F2 mice which do not express their endogenous E alpha gene. The mRNA expression of the E alpha d gene shows the same tissue distribution as the endogenous class II genes except in the case of one mouse, which carried 19 copies of the E alpha d gene. In this mouse expression of E alpha d mRNA was seen in all tissues tested. Expression of the transgene was induced by gamma-interferon in isolated macrophages from the transgenic mice. In addition, fluorescence activated cell sorter (FACS) analysis, mixed lymphocyte response and antigen-presentation experiments showed that the product of the transferred gene is expressed on the cell surface and functions as a major histocompatibility complex restriction element. Transmission of the gene occurred only with female transgenic mice, all males were infertile or did not transmit the gene, suggesting an effect of the transferred DNA sequence on male reproductive function.

Animals↗
PubMed1988

The enhancer in an MHC class II gene, in vitro and in mouso.

The E alpha class II gene of the major histocompatibility complex is expressed in a variety of immunocompetent cells. Part of the control of tissue-specific expression is mediated by a block of sequences found far upstream of the transcriptional startsite; this stretch is necessary for expression in the B lymphocytes of transgenic mice, but largely dispensable elsewhere. We review the evidence for the role of this region in E alpha transcription in transgenic animals, as well as data from transfections into tissue-culture cells, which indicate that this region has non-specific enhancer activity. We discuss possible models to explain how a non-specific enhancer can participate in cell-specific control.

Animals↗
PubMed1994

Inheritance of MHC class II genes in IDDM studied in population-based affected and control families.

The transmission of HLA-DR and DQ was compared between 46 families with at least one child affected by insulin dependent diabetes mellitis (IDDM) and 43 healthy control families. In the patient families, there was an increased transmission of DR4 (p < 0.025) and DQB1*0302 (p < 0.01) from both parents to the index patient. There was an increased transmission of DQB1*0302 (p < 0.03) from the mothers only. The non-inherited maternal haplotypes showed a significantly decreased frequency (p < 0.01) of positively associated haplotypes (DR4-DQA1* 0301-DQB1*0302, DR3-DQA1*0501-DQB1*0201) compared to all parental haplotypes in the control families. In the control families neither transmission rates nor frequencies of non-inherited haplotypes differed from those expected in the control families. In conclusion, the observed reduction of IDDM-positively associated haplotypes in patient non-inherited maternal haplotypes, but not in non-inherited paternal haplotypes, suggests that tolerance during fetal life to maternal non-inherited HLA molecules may be important to diabetes development.

Adolescent↗
PubMed1997

An isotype-specific activator of major histocompatibility complex (MHC) class II genes that is independent of class II transactivator.

Patients with one type of major histocompatibility complex class II combined immunodeficiency have mutations in a gene termed class II transactivator (CIITA), which coordinately controls the transcription of the three major human class II genes, HLA-DR, -DQ, and -DP. However, the experimentally derived B-lymphoblastoid cell line, clone 13, expresses high levels of HLADQ in the absence of HLA-DR and HLA-DP, despite its mapping by complementation analysis to this group. It was possible that one of the clone 13 CIITA alleles bore a mutation that allowed HLA-DQ, but not HLA-DR or -DP transcription. Alternatively, another factor, distinct from CIITA, might control HLA-DQ expression. We report here that ectopic expression of CIITA cDNAs derived by reverse transcriptase polymerase chain reaction from clone 13 do not restore expression of HLA-DQ in another CIITA-deficient cell line, RJ2.2.5. In addition, no CIITA protein is detectable in clone 13 nuclear extracts. In contrast, somatic cell fusion between clone 13 and RJ2.2.5 restored expression of the HLA-DQ haplotype encoded by the RJ2.2.5 DQB gene. Taken together, these data demonstrate the existence of an HLA-DQ isotype-specific trans-acting factor, which functions independently of CIITA.

Blotting, Western↗
PubMed2003

Inheritance of MHC class II genes in Lithuanian families with type 1 diabetes.

Type 1 diabetes mellitus (DM) is caused by genetic and environmental factors. Twice as many fathers as mothers of children with type 1 DM have the disease. The reason for the differences remains unclear. We looked at the transmission rates of diabetes-related alleles from parents to children with diabetes. All children with newly diagnosed type 1 DM from August 1, 1996 to August 1, 2000, aged 0 to 15 years, in Lithuania were invited to participate. Blood samples for full genetic analysis were available from 125 families. HLA DQA1, DQB1, and DRB1 typing was done on DNA extracted from peripheral blood, by polymerase chain reaction amplification, manual dot-blotting onto nylon membranes, synthetic sequence-specific oligonucleotide probe 3'-end labeling with (32)P-dCTP, and hybridization, followed by stringency washes, autoradiography, and allele calling. Frequency of diabetes risk-related alleles DQB1*0302, DQA1*0201, DR4, and DR3 was less prevalent among Lithuanian than among Swedish children with type 1 DM. Transmission rates of DR4-DQB1*0302-DQA1*0301 and DR3-DQB1*0201-DQA1*0501 haplotypes from parents were higher than expected: chi(2) (TDT) 30.56, p < 0.0001, and chi(2) (TDT) 11.26, p = 0.0008, respectively. DQB1*0302 and DR4 were significantly more frequently transmitted from both parents, but DR3 was transmitted more frequently only from mothers. Any of these alleles had similar frequencies among female and male offspring. We conclude that, besides DR4-DQB1*0302-DQA1*0301 and DR3-DQB1*0201-DQA1*0501, there are other inherited alleles that determine risk for type 1 DM among children in Lithuania. Fathers might transfer other alleles of disease susceptibility in higher frequency or mothers might provide a protective environment during pregnancy, which results in higher risk to offspring of fathers than mothers to develop diabetes.

Adolescent↗
PubMed2002

Association between the MHC class I gene HFE polymorphisms and longevity: a study in Sicilian population.

Classes I and II human leukocyte antigens (HLA) genes encode highly polymorphic heterodimeric glycoproteins involved in the control of immune responses. The HLA class I gene HFE seemingly no longer participates in immunity because it has lost its ability to bind peptides and it has acquired the ability to form complex with the receptor for iron-binding transferrin by regulating iron uptake by intestinal cells. Thus, it indirectly regulates immune responses too, because iron availability plays a role in specific and non-specific immune responses. The distribution of HFE polymorphisms in Sicilian centenarians and nonagenarians was studied to evaluate if HFE alleles might be represented differently in people selected for longevity. DNA samples were obtained from 106 young controls (age range from 22 to 55 years; 40 men and 66 women) and 35 elderly subjects (age range from 91 to 105 years; seven men and 28 women). Samples were typed for C282Y, H63D and S65C alleles using polymerase chain reaction and sequence specific primers. Among the young individuals, none was heterozygous for the C282Y or for S65C mutation. Twenty-six were heterozygous for H63D mutation. Among the elderly subjects, 11 were heterozygous for the C282Y mutation or for H63D mutation. None was heterozygous for the S65C mutation. No compound heterozygous individuals (C282Y/H63D) were found. A highly significant difference was observed in frequencies of C282Y alleles between the young and the elderly subjects on the whole. By analysing polymorphisms according to gender, heterozygous subjects for C282Y were found both in old men and in old women, but by comparing the allele frequencies to those of young people significance was attained only in women. Concerning H63D polymorphisms, no significant differences were observed, between old and young people, both in men and in women. Possession of C282Y allele, known to be associated with an increase of iron uptake, significantly increases women possibility to reach longevity. Thus, present data adds another piece of evidence to the complex puzzle of genetic and environmental factors involved in control of lifespan expectancy in humans.

Adult↗
PubMed1993

Repression of MHC class I gene promoter activity by two-exon Tat of HIV.

Major histocompatibility complex (MHC) class I molecules are the major receptors for viral peptides and serve as targets for specific cytotoxic T lymphocytes. Human immunodeficiency virus-type 1 (HIV-1) specifically decreased activity of an MHC class I gene promoter up to 12-fold. Repression was effected by the HIV-1 Tat protein derived from a spliced viral transcript (two-exon Tat). These studies define an activity for two-exon Tat distinct from that of one-exon Tat and suggest a mechanism whereby HIV-1-infected cells might be able to avoid immune surveillance, allowing the virus to persist in the infected host.

Exons↗