Showing papers in "Immunogenetics in 1985"

Genes regulating HLA class I antigen expression in T-B lymphoblast hybrids.

Abstract: Regulation of HLA class I and class II antigen expression was studied in hybrids of human T and B lymphoblastoid cell lines (LCL). The T-LCL CEMR.3 expresses no HLA class II antigens. It expresses little total HLA class I antigen and no HLA-B antigens. The B-LCL 721.174 is a radiation-induced variant immunoselected for loss of class II antigen expression. In addition to showing a deletion of all HLA-DR and DQ structural genes, 721.174 expresses no HLA-B antigens and a decreased level of HLA-A antigen compared with the parental cell line. A hybrid of 721.174 and CEMR.3 expresses class II antigens encoded by CEMR.3. Increased expression of HLA class I antigens encoded by both 721.174 and CEMR.3 was also observed. Specifically, the previously undetectable HLA-B5 and HLA-Bw6 antigens encoded by 721.174 and CEMR.3, respectively, were present on the hybrid. Increased expression of the HLA-A2 antigen encoded by 721.174 was also observed. An immunoselected variant of the hybrid lacking both CEMR.3-derived copies of chromosome 6 lost expression of the HLA-B5 antigen encoded by 721.174 and expressed a decreased amount of HLA-A2. From these data, we infer that two complementary trans-acting factors mediate enhanced expression of HLA class I antigens in the hybrid. One of these factors is provided by a gene located on chromosome 6, derived from CEMR.3. The second factor, introduced by 721.174, is the gene previously postulated to induce expression of CEMR.3-encoded class I antigens in hybrids of CEMR.3 with B-LCL.

Polymorphism of human complement component C4

Abstract: An assessment has been made of the polymorphism of human complement component C4 by comparing derived amino acid sequences of cDNA and genomic DNA with limited amino acid sequences. In all, one complete and six partial sequences have been obtained from material from three individuals and include two C4A and two C4B alleles. Differences were found between the 4 alleles from 2 loci in only 15 of the 1722 amino acid residues, and 12 lie within one section of 230 residues, which in 1 allele also contains a 3-residue deletion. In three variable positions, an allelic difference in one C4 type was common to the other types. Three nucleotide differences were found in four introns. In spite of marked differences in their chemical reactivity, the many allelic forms appear to differ in less than 1% of their amino acid residue positions. This unusual pattern of polymorphism may be due to recent duplication of the C4 gene, or may have arisen by selection as a result of the biological role of C4, which interacts in the complement sequence with nine other proteins necessitating conservation of much of the surface structure.

Mutation at I-A beta chain prevents experimental autoimmune myasthenia gravis.

Abstract: Immune response (Ir) gene(s) at the I-A subregion of the mouse H-2 complex influence susceptibility to experimental autoimmune myasthenia gravis (EAMG). To determine the importance of the Ir gene product, the Ia antigens, in EAMG pathogenesis, we studied the degree of EAMG susceptibility of an I-A mutant strain, the B6.C-H-2 bm12 (bm12), and its parent B6/Kh. According to the cellular, humoral, biochemical, and clinical manifestations of EAMG, the I-A mutation converted an EAMG susceptible strain (B6/Kh) into a relatively resistant strain (bm12). The relative resistance to EAMG induction in bm12 may be due to the lack of Ia.8 and/or la.39 determinants and/or quantitative expression of la antigens.

The HLA-AW24 gene: sequence, surroundings and comparison with the HLA-A2 and HLA-A3 genes.

Abstract: A cosmid clone containing two class I sequences was found to cause expression of the HLA-AW24 protein after transfection into mouse L cells. The restriction map of this cosmid shows extensive homology over 26 kb with the map of the HLA-A3 region obtained from cosmids of the same library, constructed with DNA from an HLA-A3/HLA-AW24 heterozygote, but diverges over the remaining 14 kb. The HLA-AW24 gene was subcloned from this cosmid and its nucleotide sequence was determined. Amino acid and, more strikingly, nucleotide sequence comparisons with other HLA alleles indicate that the A locus alleles are more closely related to each other than to alleles from other HLA loci. A very skewed distribution of silent substitutions is apparent, and the occurrence of clustered multiple substitutions hints at gene-conversion-like events.

Null alleles of the fourth component of complement and HLA haplotypes in familial systemic lupus erythematosus.

Abstract: Eight families (121 individuals) with two or more members affected with systemic lupus erythematosus (SLE) were analyzed for histocompatibility antigens (HLA-A, B, C, DR, MT, and MB) and complement antigens (C4A, C4B, and BF). These data were correlated with serological markers (antinuclear antibodies, single- and double-stranded anti-DNA, anti-SM, anti-nRNP, anti-Ro [SS-A], anti-La [SS-B], and biological false-positive tests for syphilis and clinical features. Fifteen members had SLE, and 19 had other immune diseases (subacute cutaneous lupus erythematosus, discoid lupus erythematosus, hypothyroidism, insulin-dependent diabetes mellitus, primary, Sjogren's syndrome, immune thrombocytopenic purpura, rheumatoid arthritis, and multiple sclerosis). Twenty-three healthy relatives (seroreactors) had significant titers of circulating antibodies, as did 2 of 17 spouses. There was an increased frequency of null C4 alleles in those individuals with SLE (60%) and healthy relatives (50%) as compared with spouses (24%). Multivariate analysis showed a significant association between SLE and female sex (P=.006), whereas there was no significant association revealed between female sex and other immune diseases. Patients with SLE also had a higher frequency of either C4A or C4B null alleles (P=.01) than those with immune diseases. The C4A homozygous null phenotype was more common in SLE patients than in seroreactors (P=.02). There was a higher frequency of HLA-DR2 and DR3 in individuals with SLE than in those with immune disease (P=.08), seroreactors (P=.02) and normal relatives (P =.002). One totally C4-deficient patient with SLE was identified. These families demonstrate an important association between SLE and the C4 null allele and the HLA-DR2 and DR3. These risk factors, however, cannot account for the development of disease in all individuals.

Family studies of IgA deficiency

Abstract: Seventeen immunoglobulin A (IgA)-deficient subjects and other members from 13 families were examined at HLA-A, B and DR, C4A, C4B, and Bf loci. Of the 29 independent haplotypes in the IgA-deficient: subjects, 22 included deletions, duplications, or defects at the C4 or 21-hydroxylase loci. It is suggested that there may be a gene regulating serum IgA concentrations in this same region of chromosome 6. Three main supratypes explain most of the previously reported tHLA associations with IgA deficiency. These are A1, Cw7, B8, C4AQ0, C4B1, BfS, DR3, Bw65(14), C4A2, C4B1/2, BfS, and Bw57(17), C4A6, C4B1, BfS. All three are proposed to carry a gene for IgA deficiency, while other supratypes carrying the same B allele generally do not. Other supratypes possibly associated with IgA deficiency were also identified. A survey of about 150 individuals with at least 1 of the 3 main supratypes revealed only 2 IgA-deficient subjects, and these were among the 20 that had 2 of these supratypes. This suggests the possibility of a recessive mode of inheritance, with penetrance determined by another factor which is not major histocompatibility complex-linked. All the supratypes found in this group of IgA-deficient subjects would then carry the putative recessive allele for IgA deficiency.

Activation of T lymphocytes results in an increase in H-2-encoded neuraminidase.

Abstract: The endogenous neuraminidase activity of various mouse lymphoid subpopulations and tissue compartments was examined by a sensitive fluorometric assay. These analyses indicated that activated T lymphocytes possessed a significantly higher level of intracellular neuraminidase than activated B or resting T or B lymphocytes. Examination of the level of neuraminidase in bone marrow, thymus, lymph node, and unfractionated spleen indicated that these lymphoid tissues contained significantly less neuraminidase than was detected in stimulated T cells. Kinetic studies revealed that the majority of the increase in neuraminidase activity occurred between 24 and 48 h following stimulation. Analysis of activated T lymphocytes prepared from a panel of inbred mouse strains indicated that cells from mice of theH-2 v haplotype, which possess theNeu-1 a allele and are deficient in liver neuraminidase, exhibited a level of activity which was significantly lower than that detected in stimulated T cells from other mouse strains. These results indicate that the endogenous neuraminidase activity of T lymphocytes increases upon stimulation, and that the level of this enzyme activity in lymphoid cells is also controlled by theNeu-1 locus, which is located in theH-2 region of the major histocompatibility complex.

Major histocompatibility (B) complex effects on acquired immunity to cecal coccidiosis.

Abstract: The influence of the major histocompatibility (B) complex on acquired immunity to the avian coccidium Eimeria tenella was studied in 217 F4 segregants (B2B2, B2B5, B5B5) of a cross between inbred lines 61 (B2B2) and 151 (B5B5) and segregating haplotype combinations of UNH105 (B23B23B23B24, B24B24), a noninbred line of New Hampshire chickens. Chickens were immunized at 6 weeks of age with 500 oocysts daily for 5 days, then challenged 14 days later with 10000 oocysts. Responses to infection were evaluated by cecal lesion scores, body weight gain, delayed wattle reaction (DWR), and spleen weight. The F4 segregants of genotypes B2B5 and B5B5 exhibited greater immunity to challenge than B2B2 chickens. B5B5 chickens showed a significantly greater DWR following immunization and larger spleens 6 days after the challenge than either of the other genotypes. However, both BIBS and B5B5 chickens demonstrated significantly lower lesion scores than B2B2 chickens. There were no significant differences in weight gain among these genotypes. Among 139 line UNH105 segregants, B23B23 hosts had significantly lower lesion scores than B24B24 chickens. No other differences in immune response among line UNH105 genotypes were detected.

Genetic polymorphism at the kappa chain locus in mice: comparisons of restriction enzyme hybridization fragments of variable and constant region genes.

Abstract: Variable (Vκ) and constant (Cκ) region genes of the mouse kappa light chain have been compared in inbred strains and in geographically isolated or genetically separated populations of mice by Southern blot analysis of endonuclease-restricted germline DNA. In most cases, the Cκ gene is found on a single restriction fragment while the Vκ genes of the Vκ19 and Vκ21 groups are each found on several (6–18) fragments. The restriction fragment (RF) patterns of Vκ19 and Vκ21 groups are both polymorphic when compared among inbred mouse strains. Southern blot patterns of Vκ21 and Vκ19 of inbred strains are also found among some geographically isolated populations of mice, suggesting that inbred strains acquired kappa loci from different subspecies. Some populations of geographical isolates show Vκ21, Vκ19, and Cκ contexts similar to inbred mice while more distantly related species within the genus Mus and laboratory rats show no apparent similarity in context to inbred strains. Variable region genes determining the RF patterns of Vκ19 and Vκ21 appear to be linked to each other and to the Cκ and Lyt-3 loci.

DNA polymorphism related to HLA-DR2 Dw2 in patients with narcolepsy.

Abstract: i Unitb de Recherches sur l'Immunog6n6tique de la Transplantation Humaine (INSERM U.93), Institut de Recherches sur les Maladies du Sang, H6pital Saint-Louis, 75010 Paris, France 2 Laboratoire d'Histocompatibilit6, Centre de Transfusion Sanguine de Lyon, France 3 Centre de Transfusion Sanguine et Service d'Electroencephalographie, Montpellier, France 4 D6partement de Neurologie, H6pital Neurologique, Lyon, France

Restriction fragment length polymorphism of the major histocompatibility complex of the pig.

Abstract: Human HLA cDNA probes were used to analyze the restriction fragment length polymorphism (RFLP) of the SLA major histocompatibility complex in swine. Cellular genomic DNA from 19 SLA homozygous pigs representing 13 different haplotypes was digested with restriction endonucleases Eco RI, Hind III, or Bam H1, separated by electrophoresis, and transferred onto diazobenzyloxymethyl paper by the Southern blot technique. The blots were probed with 32P-labeled class I or beta-DR class II cDNA. Depending on the haplotypes and the endonucleases used, seven to ten restriction fragments hybridized with the class I probe, and five to seven with the beta-DR probe. Their sizes ranged from 3.4 to 22 kilobase-pairs. Few bands were common to all 13 haplotypes. With all but one haplotype, identical autoradiogram patterns were obtained from unrelated, but phenotypically SLA-identical pigs, suggesting that most of the RFLP revealed were controlled by the SLA region. Further polymorphism was found in a group of seven unrelated pigs which typed serologically as SLA A15 CI B18 homozygotes but could be divided into two subgroups, with five animals in one subgroup and two in the other, when the genomic DNA was hybridized with the class I probe. When the class 11 beta-DR probe was tested on the same seven pigs, another subdivision was seen, and this correlated with MLR data. These results demonstrate that HLA class I and class II probes can be used to identify certain well-established SLA haplotypes and to identify subclasses within at least one SLA haplotype.

Haplotype study on C4 polymorphism in Japanese. Associations with MIHC Alleles, complotypes, and HLA-complement haplotypes

Abstract: Genetic polymorphism of the fourth component of human complement (C4) was investigated in 83 Japanese families which have been typed for HLA-A,-B,-C,-DR, C2, and BF. Four common C4A alleles and four common C4B alleles were observed. The allele frequencies estimated from unrelated parents were as follows: C4A3, 0.686; A4, 0.132; A2, 0.106; AQ0, 0.067; ARares, 0.009; C4B1, 0.587; B2, 0.167; B5, 0.088; and BQ0, 0.158. Eight different C4 haplotypes were observed with frequencies of more than 0.01. The estimated haplotype frequencies were as follows: C4A3-B1, 0.513; A4-B2, 0.114; A2-BQ0, 0.106; A3-B5, 0.088; AQ0-B1, 0.059; A3-BQ0, 0.047; A3-B2, 0.038; A4-B1, 0.015; and Rares, 0.021. Strong positive gametic associations were found in the following C4-HLA haplotypes: C4A2BQ0-A24, C4A2BQ0-Bw52, C4A3B5-Bw54, C4A3B5-Bw59, C4A4B2-Bw46, C4A3B5-Cw1, C4A2BQ0-DR2, and C4A3B5-DR4. Eleven complotypes were observed with frequencies of more than 0.01. C4A2BQ0 and C4A3B5 were exclusively associated with BFS-C2C. BFF was associated with C4A3B1. C2AT, C2B, and C2BH were associated with C4A3B1, A4B2, and C4A3B1, respectively. Eight different HLA-complement haplotypes were found to be characteristic of Japanese. These combinations are considerably different from those reported in Caucasoid populations.

Analysis of the sheep MHC using HLA class I, II, and C4 cDNA probes

Abstract: Four cDNA probes for the human major histocompatibility complex (MHC) were used to investigate the sheep MHC, in conjunction with serological typing for ovine lymphocyte antigen (OLA). Lymphocytes from a family (two parents and five offspring) of Romanov sheep were subjected to genomic DNA digestion by the restriction endonuclease Eco RI, followed by gel electrophoresis. A single Southern blot representing all seven individuals was then consecutively hybridized with the class I, alpha-DC, beta-DR, and C4 probes, which were originally designed to identify HLA class I, class II (DC and DR), and C4 products, respectively. Using each of the three class I/class II probes, several bands showing DNA polymorphism were detected. The segregation of these bands in the five offspring exactly paralleled the OLA haplotype segregation established by serological typing. A further eight individuals carrying haplotypes which were phenotypically identical to those in the above-mentioned family showed bands in the corresponding positions when tested with the same three probes. Using the C4 probe, no polymorphism was detected in these fifteen individuals.

The mouse Ly-17 locus identifies a polymorphism of the Fc receptor.

Abstract: The mouse Ly-17.2 alloantigen has recently been defined with both conventional and monoclonal antibodies; it identifies a locus, sited on chromosome 1, the products of which were considered to be specific for B cells. Using another Ly-17.2-specific monoclonal antibody (described herein), the tissue distribution of the Ly-17.2 antigen was shown to extend to a subpopulation of T lymphocytes and to neutrophils. This distribution is remarkably similar to that of the Fc receptor for immunoglobulin. Indeed, we now demonstrate that the Ly-17 locus codes for a polymorphism of the Fc receptor, a conclusion based upon (a) an identical tissue distribution of Ly-17.2 and FcR on both normal and tumor tissue; (b) specific inhibition of EA rosette formation by F(ab′)2 fragments of anti-Ly-17.2; (c) inhibition of the binding of the 2AG2 monoclonal rat antimouse Fc receptor antibody by Ly-17.2 antibody; (d) precipitation of an identical series of molecules by our Ly-17.2-specific antibody and by the recognized Fc receptor-specific antibody (2.4G2); and (e) the demonstration by coprecipitation that the Ly-17.2 specificity is present on Fc receptor molecules. The studies suggest that the xenogeneic monoclonal antibody (2.4G2) which recognizes an invariant site on the FcR molecule and the polymorphic site are closely associated. In addition, the studies firmly map a gene coding for or regulating the expression of the FcR to chromosome 1.

Asynchronous regulation of mouse H-2D and beta-2 microglobulin RNA transcripts

Abstract: The major transplantation (or H-2) antigens in the mouse are cell-surface glycoproteins composed of a heavy chain and a light chain, the beta-2 microglobulin (β2m). The expression of these proteins is regulated during development. Embryonic cells at early stages of development do not express these proteins. On the other hand, these molecules are present on the surface of all adult somatic cells. We investigated whether the expression of both chains was coordinately regulated. Using specific single-stranded DNA probes in an S1 nuclease analysis, we compared the relative amounts of H-21) and β2M transcripts in normal tissues, in transformed cells, and during embryonic development. Our results show that (1) the steady state level of β2m transcripts varies from one adult organ to another, while that of H-2D transcripts stays approximately the same; (2) upon transformation, the amount of H-2D-specific mRNA increases drastically, while the β2m mRNA level remains constant; (3) whereas the quantity of β2m mRNA increases during early development, the amount of H-2D mRNA remains at a very low level. These data suggest that the regulation of H-2D and β2m genes are not identical and that their activation during development is not synchronous.

Susceptibility to IDDM is marked by MHC supratypes rather than individual alleles.

Abstract: 107 patients with insulin-dependent diabetes mellitus (IDDM) were typed for HLA A, B, C, and DR antigens, and for complement C4A, C4B, and Bf alleles, and the results were compared with those of a combined reference group of 332 appropriately matched healthy subjects. Supratypes (allelic combinations) were identified from the phenotype of each group, and it was shown that the frequency of several supratypes is increased in patients with IDDM, in particular supratypes (A1 Cw7) B8 C4AQ0 C4B1 BfS DR3 (P = 0.0001), (A30 Cw-) B18 C4A3 C4BQ0 BfF1 DR3 (P = 0.0003), (A2 Cw3) B62 C4AR C4B2.9 BfS DR4 (P = 0.0002), and three other supratypes including DR4. It was also shown that increases in the frequency of individual alleles are secondary to increases in supratype frequency. Moreover, supratypes appeared to interact; the presence of two relevant supratypes being particularly important. The absolute risk of IDDM was approximately 0.5 in subjects who were homozygous for B18 C4A3 C4BQ0 BfF1 DR3. We concluded that genetic susceptibility is best recognized by MHC supratypes rather than isolated alleles, and that supratype combinations make the identification of even greater disease risk possible.

T Helper and T suppressor cells are restricted by the A and E molecules, respectively, in the F antigen system

Abstract: The role of the A and E molecules as restriction elements was examined in the F antigen system. In the mouse the only responder haplotype known to date isk, and blocking studies with a monoclonal antibody show that in vitro T-cell proliferation is restricted by the Ak molecule. The (CBA × DBA/2) F1 hybrid, which is a responder x nonresponder cross, is itself a nonresponder in terms of E-specific antibody production. Up to 10 days after priming, (CBA × DBA/2) F1 T cells exhibited an E-specific proliferative response, but this diminished rapidly at later times. This diminution could be blocked with an E-specific monoclonal antibody, suggesting that suppression is restricted by the E molecule.

The Pgp-1 antigen is expressed on early fetal thymocytes.

Abstract: The Pgp-1 glycoprotein is expressed on the bone marrow prothymocyte and on a class of intrathymic progenitor cells in the adult animal. Only 5% of adult thymocytes are strongly Pgp-1+. When fetal thymocytes of day 13–14 of gestation are examined by flow cytometric analysis, 80–90% of thymocytes are Pgp-1+, while the bulk of thymocytes are Thy-1−. By day 15–16, the percentage of Pgp-1+ cells begins to fall while nearly all cells become Thy-1+. Two-color immunofluorescence indicates that many Pgp-1+ cells are Thy-1+. The percentage of Pgp-1+ cells continues to fall over the next several days, reaching adult levels by day 19. These observations are consistent with the interpretation that at least some classes of thymocyte progenitors are Pgp-1+.

Experimental allergic orchitis in mice. I. Genetic control of susceptibility and resistance to induction of autoimmune orchitis.

Abstract: Inbred strains of mice were studied for their susceptibility to the induction of experimental allergic orchitis after sensitization with mouse testicular homogenate in complete Freund's adjuvant accompanied by injections of extract from Bordetella pertussis. Susceptibility to autoimmune orchitis was found to be linked to the major histocompatibility complex in BALB/c and C57BL/10 mice and mapped to genes encoded within the H-2Dd region. In five of six groups of bidirectional (susceptible X resistant)F1 hybrids, H-2Dd-linked susceptibility was inherited as a dominant autosomal trait. However, in (BALB/cByJ X DBA/2J)F1 and (DBA/2J X BALB/cByJ)F1 hybrids, dominant autosomal resistance to the induction of autoimmune orchitis was observed. Backcross analysis between the resistant F1 hybrid and the susceptible BALB/cByJ parent suggests that a single independently segregating DBA/2J locus is capable of negating H-2Dd-linked susceptibility, and controls resistance to the induction of autoimmune orchitis.

Consequences of a single Ir-gene defect for the pathogenesis of lymphocytic choriomeningitis.

Abstract: The H-2L d allele has been identified by others as the sole Ir gene in the H-2 d haplotype for the cytotoxic T lymphocyte (CTL) response to mouse lymphocytic choriomeningitis virus (LCMV). The BALB/c-H-2 dm2 (C-H-2 dm2 ) mutant lacks H-2L d , and thus should be ideal for assessing the contribution of virus-immune CTL to LCM immunopathology. Comparison of the C-H-2 dm2 mice with congenic BALB/c mice revealed that there is a delay of about 24 h in the onset of severe inflammatory process and symptoms in the mutant strain, but the absence of H-2L d did not prevent the later development of fatal disease in mice injected intracerebrally (i.e.) with neurotropic LCMV. This could indicate that virus-immune CTL are not the major mediators of clinical LCM. Spleen cells from LCMV-primed BALB/c mice did not show CTL activity for LCMV-infected C3H.OH, C-H-2 dm2 , or (CBA × C-H-2 dm2 )F1 target cells. However, immune lymphocytes from both the mutant and the F1 strains lyse virus-infected BALB/c cells. Furthermore, BtO.HTG and, in some experiments, B10.A(5R) mice generated CTL lytic for LCMV-infected BALB/c, C-H-2 dm2 , and (CBA × CH-2 dm2 )F1 macrophages. Apparently H-2L d is immunodominant in the H-2d restricted response to LCMV. However, in the absence of H-2L d , it seems that H-2K d and, to a lesser extent, H-2D d also serve as Ir genes for the CTL response in this infection. Even so, the absence of the H-2Ld-restricting element results in a disease process which is either delayed in onset or less severe.

Structure of a functional rabbit class I MHC gene: similarity to human class I genes.

Abstract: Studies of rabbit major histocompatibility complex proteins have suggested that rabbits express only a single class I antigen, in contrast to most mouse strains (H-2K, D, and L) and man (HLA-A, -B, and -C), which express three. To explore the significance and the molecular basis of this apparent species difference, we have characterized the expressed class I protein and a corresponding cDNA clone from the rabbit cell line RL-5, which is derived from the inbred B/J rabbit strain. As an extension of these analyses, this report documents the genomic sequence of a gene, designated 19-1, which encodes the same histocompatibility antigen expressed in RL-5. The availability of the corresponding full-length cDNA and amino-terminal protein sequence indicates the fully functional nature of the 19-1 gene and allows presumptive assignment of the transcription start site and delineation of exon/intron boundaries. Comparisons of the rabbit gene with homologous human and mouse sequences reveal a striking similarity between 19-1 and human genes in both exon/intron organization and specific nucleotide sequences; this close similarity allows tentative identification of previously unrecognized transcriptional start sites in the human genes.

An H-2K gene of the tw32 mutant at the T/t complex is a close parent of an H-2Kq gene.

Abstract: Two recombinant mice have been recovered from the progeny of Ttf/tw32+ animals They have lost the tw32 lethality factor(s) and gained tufted, presumably from the T chromosome Southern blot analysis of class I genes of these two new partial tPA027 and tPA286 haplotypes indicates that they have retained at least part of the major histocompatibility complex of the tw32 chromosome (H-2 haplotype H-2w28) We have prepared a phage library of Eco RI-digested DNA from homozygous tPA027 animals Upon screening the library with a cDNA probe specific for H-2K genes, we isolated a class I gene displaying all of the distinctive features of a genuine H-2K gene, and which could thus be defined as an H-2Kw28 gene The H-2Kw28 gene is 92–95% homologous to H-2Kband H-2Kdgenes and differs significantly from the other class I genes sequenced so far Homology with the H-2Kbsequence reaches nearly 100% in the 3′ part of the H-2Kw28 gene Moreover, the homology with an H-2KqcDNA sequence reaches 998% Several hypotheses can account for the near identity of H-2Kb, H-2Kq,and H-2Kw28 gene sequences: either recombination between H-2w28 and H-2band H-2qsequences occurred before or at thetime the strain was established, or the class I genes of the tw32 chromosome and the H-2band H-2qgenes found in inbred strains of mice have separated from each other rather recently

DNA polymorphism of the C2 and factor B gene.

Abstract: Factor B and the second component of complement (C2) in man are encoded within the major histocompatibility complex by single loci that are less than 1 kb apart. A 2.3 kb factor B-specific cDNA probe has been used to examine, by Southern blot analysis, the genomic DNA of individuals typed for C2 and factor B by protein electrophoresis. We have identified a restriction fragment length polymorphism using the endonuclease Taq I, which subdivides haplotypes carrying both the common variant of C2 (C2C) and the fast (F) variant of factor B. This DNA polymorphism has been mapped to lie in the C2 gene and represents a new genetic marker not defined by protein electrophoresis. This polymorphism may serve as a useful marker in the genetic analysis of diseases that are related to the major histocompatibility complex.

Syrian hamster DNA shows limited polymorphism at class I-like loci.

Abstract: The class I gene products of the Syrian hamster major histocompatibility complex are unique in that they lack functionally detectable polymorphism Mouse cDNA and hamster genomic probes were used to analyze the hamster class I gene family using genomic Southern hybridization These studies revealed that the hamster possesses a complex class I multigene family and that it shares extensive sequence homology with the corresponding mouse sequences Unlike the mouse, however, the Syrian hamster demonstrates only limited restriction endonuclease polymorphism in these genes These results suggest that the lack of detectable polymorphism in this species is directly related to limited DNA polymorphism The data presented here support the hypothesis that this species has undergone an evolutionary bottleneck, i e, that all surviving members of the species arose from a limited number of progenitors

Polymorphism in mouse and human class I H-2 and HLA genes is not the result of random independent point mutations

Abstract: Sufficient mouse H-2 and human HLA class I gene sequences have become available to make a statistical analysis of nucleotide variations within the multigene families possible. In the H-2 and HLA families, a group of four H-2K allelic sequences and three HLA-A sequences were compared with a group of four non-H-2 and three non-HLA-A sequences, respectively. Simple calculations show that nucleotide variations in each group do not occur in a random independent fashion. It is therefore possible that a number of mutations are “concerted” between the subgroups. Interestingly, these concerted mutations are clustered and distributed almost exclusively in the 5′ end of H-2 and HLA genes, which is very rich in GC nucleotides, and where the dinucleotide CpG is particularly frequent. The general concept of unequal repair is proposed as the basis of a model which is supported by these observations.

Experimental allergic orchitis in mice. II. Association of disease susceptibility with the locus controlling Bordetella pertussis-induced sensitivity to histamine.

Abstract: Susceptibility to the induction of murine autoimmune orchitis was found to be associated with the locus controlling Bordetella pertussis-induced sensitivity to the vasoactive amine, histamine. Only those inbred and H-2 congenic strains of mice possessing both the H-2d haplotype and the locus for susceptibility to B. pertussis-induced sensitivity to histamine developed autoimmune orchitis. In addition, segregation analysis of backcross generation mice also demonstrated a high degree of correlation between susceptibility both to disease and to histamine sensitization, which was indicative of additional multigene control. Pertussigen-histamine sensitization factor (P-HSF) was only effective in eliciting disease when it was administered on the same day, or within a period up to 6 days following sensitization with mouse testicular homogenate-emulsified in complete Freund's adjuvant. P-HSF induced sensitivity to histamine was not found to be associated with an increase in the vascular permeability of target tissue. Thus, B. pertussis-induced sensitivity to histamine appears to play a more crucial role during the sensitization phase of autoimmune orchitis induction, rather than at the inflammatory or effector phase of the disease.

Polymorphisms within the HLA-DRw6 haplotype. II. Protein charge heterogeneity reflects MLC subtyping of HLA-DRw6 homozygous cells.

Abstract: We have analyzed the HLA class II gene products from HLA-DRw6 homozygous cells. Epstein-Barr virus-transformed B-cell lines were internally labeled with [35S]-methionine. An NP-40 lysate of the cells was subjected to immunoprecipitation, first with a DRw52-like-specific monoclonal antibody and subsequently with a DR-specific framework antibody. The DR region-encoded gene products were analyzed by one-dimensional gel isoelectric focusing and two-dimensional gel electrophoresis. It is shown that DRw6 homozygous cell lines contain at least two nonallelic DR β chains, one carrying a DRw52 determinant and one DRw52-negative population. Both chains appear to be polymorphic between the cellularly defined subtypes of DRw6. The determinant responsible for the differential mixed lymphocyte culture reactivity of Dw18 and Dw19 cells resides on the DRw52-positive population, whereas the Dw6-Dw9 differences are attributed to determinants on both populations of DR light chains. The Dw16-derived DRw52+ chain much resembles the Dw18 DRw52+ light chain whereas there is a clear-cut difference between these two subtypes in the DRw52− population. We conclude that, for DRw6 homozygous cells, the cellularly recognized D determinants are probably located on DR-encoded molecules, both DRw52+ and DRw52−, and that charge shift of these chains is at least partly responsible for differential recognition of these cells in mixed lymphocyte cultures.