Showing papers in "Immunogenetics in 1990"

Nomenclature for the major histocompatibility complexes of different species: a proposal

Abstract: The major histocompatibility complex (MHC) has been given different names in different species (Klein 1986). It is designatedH-2 in the mouse, HLA in humans, B in the domestic fowl, RT1 in the rat, and Smh in the mole rat. In most other species that have been studied, the MHC is referred to by the LA symbol (for lymphocyte or leukocyte antigen), prefixed by an abbreviation of the species’ common name. Thus, it is called ChLa in the chimpanzee, GoLA in the gorilla, RhLA in the rhesus macaque, RLA in the rabbit, BoLA in the domestic cattle, SLA in the pig, and so on. This practice has two problems associated with it. First, MHC products are expressed on many other tissues in addition to lymphocyte or leukocyte (and lymphocytes express many other antigens in addition to those controlled by the MHC) and their antigenicity is secondary to their biological function. Second, the use of common names to identify a species is a potential source of confusion. Common names are notoriously vague and imprecise. The designation “lemur”, for example, can refer to any of the genera Lemur, Hapalemur, Varecia, Lepilemur; Avahi, Propithecus, and Indri, of which only the first four belong to the family Lemuridae; the last three are members of the family Indriidae. A “bushbaby” can be a Galago, Otolemur, or Euoticus. A “mouse” could be a Notomys, ylcomys, Uranomys, Pogomys, Chiruromys, Chiropodomys, Neohydromys, and so on. Obviously, common names not only fail to identify the species appropriately, they often do not even identify the genes or the family. If the trend in choosing common names for MHC symbols were to continue, chaos would soon ensue because we can expect MHCs in many different species to be identified in the future.

Structure and expression of the three MHC-linked HSP70 genes.

Abstract: A duplicated locus encoding the major heat shock-induced protein HSP70 is located in the major histocompatibility complex (MHC) class III region 92 kilobases (kb) telomeric to the C2 gene. Nucleotide sequence analysis of the two intronless genes, HSP70-1 and HSP70-2, has shown that they encode an identical protein product of 641 amino acids. A third intronless gene, HSP70-Hom, has also been identified 4 kb telomeric to the HSP70-1 gene. This encodes a more basic protein of 641 amino acids which has 90% sequence similarity with HSP70-1. In order to investigate the expression of the three (MHC)-linked HSP70 genes individually by northern blot analysis, we have isolated locus-specific probes from the 3' untranslated regions of the genes. The HSP70-1 and HSP70-2 genes have been shown to be expressed at high levels as a approximately 2.4 kb mRNA in cells heat-shocked at 42 degrees C. HSP70-1 is also expressed constitutively at very low levels. The HSP70-Hom gene, which has no heat shock consensus sequence in its 5' flanking sequence, is expressed as a approximately 3 kb mRNA at low levels both constitutively and following heat shock.

Rapid HLA-DPB typing using enzymatically amplified DNA and nonradioactive sequence-specific oligonucleotide probes.

Abstract: A simple and rapid method for characterizing the polymorphism at the HLA-DPB1 locus has been developed. The procedure involves the selective amplification of the polymorphic second exon of the DPB1 locus by the polymerase chain reaction (PCR), followed by hybridization of the amplified DNA with 15 nonisotopic sequence-specific oligonucleotide probes. There are no sequences within the second exon of the DPB1 locus that uniquely define an allele; rather, each allele appears to arise from the shuffling of a limited number of polymorphic nucleotide sequences in six regions of variability. Consequently, individual alleles are identified by the pattern of hybridization of the 15 probes. Two formats for typing are described. In Format I (the dot-blot), the amplified DNA is ultraviolet (UV) cross-linked to a nylon membrane and hybridized with the oligonucleotide probes which are covalently labeled with horseradish peroxidase (HRP). In Format II (the reverse dot-blot), the oligonucleotides, which have poly-T tails, are bound to the membrane and the immobilized array of probes is hybridized to the PCR product which has incorporated biotinylated primers during the amplification process. In both formats, hybridization is detected by a simple colorimetric reaction. The application of this technology to the fields of tissue typing and individual identity is discussed.

Genetic basis of the effects of ultraviolet light B on cutaneous immunity. Evidence that polymorphism at the Tnfa and Lps loci governs susceptibility.

Abstract: The ability of local ultraviolet B (UVB) irradiation to impair the induction of dinitrofluorobenzene (DNFB)-specific contact hypersensitivity (CH) in mice has been shown to be genetically determined. We have explored the possibility that the mouse Tnfa and Lps loci are involved. We demonstrate that C3H/HeN (Lps n strains are UVB-susceptible, whereas C3H/HeJ (Lps d ) strains are UVB-resistant. Our results indicate that local intradermal (ID) injection of mouse recombinant tumor necrosis factor-alpha (TNFa) into sites painted with DNFB impaired the induction of CH, and in a dose response experiment the effect was found to be more marked in C3H/HeN than in C3H/HeJ. Systemic administration of neutralizing TNFa-specific antibody reconstituted the UVB-induced defect in induction of CH in UVB-susceptible mice, confirming that TNFa is a major mediator of the deleterious effects of UVB on induction of cutaneous immunity. The UVB-susceptibility trait (revealed by effects on CH) correlates positively with a recently described restriction fragment length polymorphism (RFLP) at the Tnfa locus (allele b) and with the wild-type Lps n allele. These results suggest that appropriate alleles at the Tnfa and Lps loci conspire to render mice susceptible to the impairment of CH induction by UVB. We propose that the mechanism may function through the capacity of UVB to elicit excessive local (cutaneous) production of TNFa, which mediates the immune defect.

The nucleotide sequence of bovine MHC class II DQB and DRB genes.

Abstract: The nucleotide sequences of most of the exons and parts of the introns of twoBoLA-DQB genes and twoBoLA-DRB genes have been determined. The structure of these genes is very similar to that of human major histocompatibility complex (MHC) class II genes. The twoDQB genes probably represent true alleles. Based on the exons sequenced, bothDQB genes and one of theDRB genes seem to be functional. The otherDRB gene is a pseudogene; stopcodons are found in the exons encoding the second and transmembrane domain and, furthermore, a 2 base pair (bp) deletion has occured in the leader exon which places the initiation start codon out of frame. Also in this pseudogene, an almost perfect inverted repeat of 200 bp is found flanking the exon encoding the first domain, which might have been the result of a duplication/inversion event. The sequences presented in this paper do not contain any repetitions. Therefore, DNA fragments containing these sequences can be used as homologous bovine probes in restriction fragment length polymorphism (RFLP) analysis to study disease association in cattle.

The nucleotide sequence of the bovine MHC class II alpha genes: DRA, DQA, and DYA

Abstract: The nucleotide sequence of the exons 2, 3, and 4, and parts of the intervening sequences of aBoLA-DRA and-DQA gene and one other class IIBoLA-A gene have been determined. The structure of theBoLA-DRA and-DQA gene was found to be very similar to that of the corresponding human HLA class II genes. An analysis of the structure of the other class IIBoLA-A gene showed that thisA gene was clearly very different from both the humanA genes and the bovineDRA andDQA genes. The results indicate that this other type of class IIA gene probably represents the class II gene that has already been identified in restriction fragment length polymorphism (RFLP) studies asBoLA-DYA. Since no clear homologue of this presumedBoLA-DYA gene was found among the human HLA class II genes, these results indicate that, at least as far as theA genes are concerned, a distinct class II gene is present in cattle.

Organization of a functional chicken class II B gene

Abstract: Five class II (B-L) B genes are encoded in the major histocompatibility complex (MHC) of chickens of the B12 haplotype. We report here the nucleotide sequence of one of these genes, B-LBII, as well as the primary structure of a corresponding cDNA. The organization of B-LBII, its 5' flanking region including the promotor region, and the amino acid sequence of its product are compared to mammalian class II B genes and to the previously described B-LBIII gene, which probably is a pseudogene since no B-LBIII transcript could be identified. The 5' flanking region of B-LBII exhibits homologs of transcription-controlling sequence motifs, namely S, X, X2, and Y boxes, of class II A and B genes of rodents and man. However, the promotor region of B-LBIII lacks an equivalent of the S box, displays two nucleic acid substitutions in the core sequence of the Y box, and exhibits a 16 base pair (bp) deletion upstream of the site of initiation of transcription. Therefore, an aberrant promotor region is likely to account for the pseudogene-like nature of B-LBIII, which displays open-reading frames in all exons. The data obtained with the functional B-LBII gene are in line with our previous interpretation that both genomic organization and tertiary structure of class II beta molecules are remarkably conserved between birds and mammals.

Human CD28 and CTLA-4 Ig superfamily genes are located on chromosome 2 at bands q33-q34.

Abstract: CD28 is a cell surface molecule present on most peripheral T cells which has been implied in the amplification of the T-cell response in vitro. Using in situ hybridization on human prometaphase cells, we have found that the human CD28 gene maps to chromosome 2 at bands q33-q34, as shown previously for the CTLA-4 gene. CD28 and CTLA-4 are both members of the Ig superfamily, where they define a subgroup of membrane-bound single V domains. Their chromosomal proximity and their close structural relationship suggest that these two genes could be the result of the duplication of a common evolutionary precursor and may share some functional properties.

HLA-DR typing using DNA amplification by the polymerase chain reaction and sequential hybridization to sequence-specific oligonucleotide probes.

Abstract: A series of sequence-specific oligonucleotides (SSOs) have been used to type alleles at the HLA-DRB1 locus. Genomic DNA was amplified to high copy number by the polymerase chain reaction (PCR) and hybridizations of the dot-blotted, amplified DNA to a series of 14 SSOs enabled the identification of the major specificities DR1-DRw14. Certain alleles (DR3 and DR4) could be rapidly and accurately identified by running the products of allele-specific amplification of genomic DNA on agarose gels. This approach facilitated the typing of serological specificities such as subtypes of DR3 (DRw17 and DRw18) as well as alleles previously detected by the mixed lymphocyte reaction including subtypes of DR4 (Dw4, Dw10, Dw13, Dw14, and Dw15). The HLA-DR types obtained by SSO probing conformed to rules of Mendelian inheritance when they were applied to a series of 75 families. A full DR type could be obtained from many individuals simultaneously without needing to separate or store viable lymphocytes. Thus, this technique may have considerable implications for the analysis of disease associations with HLA class II alleles, particularly in circumstances where facilities for the initial preparation and storage of the samples may be limited.

Identification of mRNA that encodes an alternative form of H-CAM(CD44) in lymphoid and nonlymphoid tissues.

Abstract: The cluster of differentiation 44 (CD44), hereafter referred to as H-CAM(CD44), represents a novel class of polymorphic (M r 80 000–215 000) cell adhesion molecules that are involved in cell-cell and cell-matrix adhesion events in a variety of organ systems. We report the detection of distinct mRNAs, in both hematopoietic and nonhematopoietic human cell lines, that encode H-CAM(CD44) with different cytoplasmic domains. Genomic Southern blot analyses indicate that the exons encoding these two cytoplasmic domains are located on the same ∼ 16 kilobase (kb) Eco RI restriction fragment. Restriction endonuclease and Southern blot analyses performed on polymerase chain reaction (PCR) amplification copies of these mRNAs confirm that their sequences correspond with previously reported cDNA sequences. A consensus splice donor site which is conserved in human, baboon, and mouse mRNAs that encode a molecule with an elongated cytoplasmic domain (H-CAM-L) is utilized to generate a distinct but low-abundance mRNA species that encodes H-CAM(CD44) with a truncated cytoplasmic domain of only three amino acids (H-CAM-S). Estimations of the relative abundance of these mRNA species in B-lymphoblastoid cells using the PCR amplification technique exhibit average H-CAM-L/H-CAM-S ratios ranging between 100 and 200. Therefore, H-CAM(CD44)-mediated adhesive events may be regulated through a differential capacity of H-CAM-L and H-CAM-S to interact with the cytoskeleton and to participate in intracellular signaling events.

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

Abstract: We have investigated theHLA-DRB and -DQB gene polymorphism in 131 myasthenia gravis (MG) patients. TheHLA genotypes in these patients were assigned by means of restriction fragment length polymorphism (RFLP)-definedDR-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-positiveDR-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 DRwl5-Dw2-positive haplotypeT-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.

Recombinational hotspot specific to female meiosis in the mouse major histocompatibility complex.

Abstract: The wm7 haplotype of the major histocompatibility complex (MHC), derived from the Japanese wild mouse Mus musculus molossinus, enhances recombination specific to female meiosis in the K/A beta interval of the MHC. We have mapped crossover points of fifteen independent recombinants from genetic crosses of the wm7 and laboratory haplotypes. Most of them were confined to a short segment of approximately 1 kilobase (kb) of DNA between the A beta 3 and A beta 2 genes, indicating the presence of a female-specific recombinational hotspot. Its location overlaps with a sex-independent hotspot previously identified in the Mus musculus castaneus CAS3 haplotype. We have cloned and sequenced DNA fragments surrounding the hotspot from the wm7 haplotype and the corresponding regions from the hotspot-negative B10.A and C57BL/10 strains. There is no significant difference between the sequences of these three strains, or between these and the published sequences of the CAS3 and C57BL/6 strains. However, a comparison of this A beta 3/A beta 2 hotspot with a previously characterized hotspot in the E beta gene revealed that they have a very similar molecular organization. Each hotspot consists of two elements, the consensus sequence of the mouse middle repetitive MT family and the tetrameric repeated sequences, which are separated by 1 kb of DNA.

Correlation between the Vβ4^+CD8^+T-cell population and the H-2d haplotype.

Abstract: The Vs4+ T-cell population was examined with a newly established antibody, KT4, specific for Vs4. Between 4.8% and 19.4% of CD3+ peripheral T cells from various inbred strains of mice or Fl hybrids expressed Vs4. The CD4 T-cell population had higher numbers of Vβ4+ T cells (5.5%–20.6%) than the CD8 T-cell population (2.5%–10.7%). Deletion of certain Vβexpressing T cells due to the presence of the Mlsa antigen and/or the absence of certainTcrb-V genes increased relative numbers of Vs4+ T cells. The data suggest that Vβ4+ CD8+ T cells might be positively selected by H-2d molecules.

Allelic variation in the DR subregion of the canine major histocompatibility complex.

Abstract: Allelic variation in theR subregion of the canine major histocompatibility complex (DLA) has been analyzed by nucleic acid sequencing of cDNA clones of DRB genes amplified in vitro by the reverse transcriptasepolymerase chain reaction (RT-PCR). Sequence analysis of a panel of 19 homozygous typing cell dogs representing 12 different DLA-D types (defined by mixed leucocyte reaction) demonstrated the presence of one expressed DRB locus with at least nine distinct alleles in the dog. Unique DLA-DRB alleles were found in the DLA-D types Dw1, Dw3, Dw4, Dw8 (workshop assignments) and D4, D6, D7, D8, and D9 (Seattle assignments). In contrast, the DRB genes of the remaining three DLA-D types (D1, D10, and D16) were identical to those of Dw3/Dw4 (for D I), Dw8 (for D10), and D6 (for D16). The nucleotide sequences of all nine DLA-DRB alleles were typical of functional major histocompatibility complex (MHC) class II 0 chains and contained three allelic hypervariable regions (HVRs) in the 01 domain at positions 8-16, 26–39, and 57–74. At each variable residue, two to five amino acid substitutions were found. The most polymorphic residues were located at positions 37 (with five amino acid substitutions), 11, 13, 28, and 71 (each with four substitutions). The DLA-DRB alleles had 96 % -99 % overall nucleotide sequence similarity and 93k-99% amino acid sequence similarity with each other. Cluster analysis of the nucleotide and predicted amino acid sequences subdivided the DLA-DRB alleles into three major allelic groups which may represent the canine counterparts of the supertypic groups described in man.

Nomenclature for factors of the HLA system, 1989 : the WHO nomenclature committee for factors of the HLA system

Abstract: This report, taking into account only new data on DNA sequences of alleles and of three new loci, therefore concerns only the naming of new alleles and loci defined by nucleotide or inferred amino acid sequences. It should therefore be considered as a supplement to and used in conjunction with the 1987 report cited above

Hypervariability of intronic simple (gt)n(ga)m repeats in HLA-DRB genes.

Abstract: We have investigated the extent of DNA variability in intronic simple (gt)n(ga)m repeat sequences and correlated this to sequence polymorphisms in the flanking exon 2 of HLA-DRB genes. The polymerase chain reaction (PCR) was used to amplify a DNA fragment containing exon 2 and the repeat region of intron 2. The PCR products were separated on sequencing gels in order to demonstrate length hypervariability of the (gt)n(ga)m repeats. In a parallel experiment, the PCR products were cloned and sequenced (each exon 2 plus adjacent simple repeats) to characterize the simple repeats in relation to the HLA-DRB sequences. In a panel of 25 DRB1, DRB4, and DRB5 alleles new sequences were not detected. Restriction fragment length polymorphism (RFLP) subtyping of serologically defined haplotypes corresponds to translated DNA sequences in 85% of the cases, the exceptions involving unusual DR/DQ combinations. Many identical DRB1 alleles can be distinguished on the basis of their adjacent simple repeats. We found group-specific organization of the repeats: the DRw52 supergroup repeats differ from those of DRB1*0101, DRB4*0101, and DRB5*0101 alleles and from those of pseudogenes. Finally, we amplified baboon DNA and found a DRB allele with extensive similarity to DRB1 sequences of the DRw52 supergroup. The simple repeat of the baboon gene, however, resembles that of human pseudogenes. In addition to further subtyping, the parallel study of polymorphic protein and hypervariable DNA alleles may allow conclusions to be drawn on the relationships between the DRB genes and perhaps also on the theory of trans-species evolution.

Conservation of the central MHC genome: PFGE mapping and RFLP analysis of complement, HSP70, and TNF genes in the goat.

Abstract: A degree of conservation of the genes located between class II and class I [central major histocompatibility complex (MHC) genes] is apparent among mammalian species including primates and the mouse. Few others have been analyzed. The caprine MHC is of particular interest, since it has recently been observed that susceptibility to a lentivirus-induced polyarthritis (caprine arthritis) segregates with serologically defined MHC class I antigens. This arthritis resembles, in a number of respects, rheumatoid arthritis in man. Human cDNA probes were used to examine the caprine central MHC and class I and II genes by restriction fragment length polymorphism (RFLP) and by pulsed field gel electrophoresis (PFGE) in order to define the polymorphism and linkage of central MHC genes to class I and class II genes. An outbred population of dairy goats (Saanen, British Alpine, Anglo Nubian, and Toggenberg) was examined for class I and class II RFLPs. Both regions were found to be highly polymorphic. The number of fragments hybridizing to an HLA-B7 probe after Eco RI, Bam HI, Bgl II, or Hind III digestion suggests there may be 10–13 class I genes. The degree of polymorphism was comparable to that reported in the mouse. Limited polymorphism was found in the central MHC genes. The caprine C4 and CYP21 genes were duplicated and demonstrated RFLP with Bam HI, Hind III, Eco RV, and Taq I. An infrequent Taq I C2 polymorphism was found. PFGE revealed substantial conservation of both the order and linkage of the central MHC genes when compared with mous and man. C4, C2, CYP21, HSP70, and tumor necrosis factor (TNF) genes are all located within 800 kilobase (kb) of the class I loci. Distant from the class I region, the C4, C2, and CYP21 genes are linked on a short genomic segment (180 kb Not I and 190 kb Pvu I fragments). HSP70 cohybridizes with the complement genes on a 380 kb Mlu I fragment. Linkage of HSP70, TNF, and class I genes was found on a single Not I fragment (610 kb). TNF and class I cohybridize on Pvu I (730 kb) and Not I (610 kb) fragments. Conservation of a similar central MHC genomic structure across species argues for functional interaction between the central MHC genes. We postulate selection for these central MHC genes through their role as non antigen-specific regulators of immune response.

IL9 maps to mouse chromosome 13 and human chromosome 5

Abstract: Mouse and human cDNA clones encoding the T-cell and mast cell growth factor P40, now designated IL-9, were used to identify DNA restriction fragment length polymorphisms (RFLPs) in sets of somatic cell hybrids and between inbred strains of mice and interspecific backcross progeny. Segregation of mouse and human chromosomes among somatic cell hybrids indicated a location on mouse chromosome 13 and human chromosome 5. RFLPs were identified among inbred strains of mice. Analysis of chromosome 13 alleles for Tcrg, Dhfr, and Il-9 in an interspecific cross between Mus musculus and NFS/N or C58/J mice indicates that IL9 is distal to Tcrg and proximal to Dhfr.

Structure and expression of a chicken MHC class I gene.

Abstract: In the present communication we report the primary structure of an expressed chicken class I gene, B-FIV, of the CB-B 12 haplotype

The human leucocyte surface antigen CD53 is a protein structurally similar to the CD37 and MRC OX-44 antigens.

Abstract: CD53 is an N-glycosylated pan-leucocyte antigen of 35–42 000 Mr. The sequence of the CD53 polypeptide deduced from a cDNA clone is 219 amino acids in length. It appears to lack a conventional leader sequence because the deduced NH2-terminal amino acid sequence is very similar to the rat MRC OX-44 and human CD37 antigens. The CD53 molecule is likely to consist of four transmembrane regions and a major extracellular hydrophilic loop containing two potential N-glycosylation sites. It is suggested that the CD53 glycoprotein is the true human homologue of the rat OX-44 antigen, rather than the CD37 antigen of more restricted expression and lower NH2-terminal sequence similarity to OX-44.

The germline repertoire of T-cell receptor beta chain genes in patients with relapsing/remitting multiple sclerosis or optic neuritis

Abstract: We have studied the germline repertoire of T-cell receptor β chain genes in 20 patients with monosymptomatic optic neuritis (ON), which may mark the onset of MS, and in 37 patients with relapsing/remitting (R/R) MS; we compared this repertoire to that of 99 unselected, unrelated healthy Danes

Complement C4 and heat shock protein 70 (HSP70) genotypes and type I diabetes mellitus.

Abstract: Type I diabetes is strongly associated with the major histocompatibility complex (MHC) class II region (DR and DQ loci), and to a lesser extent the class III region (complement C4 loci). Restriction fragment length polymorphism analysis was employed to investigate the C4 and heat shock protein 70 (HSP70) loci of 176 patients with type I diabetes and 92 healthy controls. In the patient population there was an excess of deletions of the C4A locus (48.5% vs 22.1%, P < 0.0005). The HSP70 probe in conjunction with the restriction endonuclease Pst I detects two alleles of 9 or 8.5 kilobases (kb). The 8.5 kb allele was significantly increased in the patient group compared to healthy controls (0.569 vs 0.353, respectively, P < 0.0005). Furthermore, a C4A deletion nearly always occurred with the 8.5 kb HSP70 allele, suggesting that it may be a marker of the HLA-A1, B8, C4A deletion, DR3 extended haplotype.

Antigens similar to major histocompatibility complex B-G are expressed in the intestinal epithelium in the chicken.

Abstract: A monoclonal antibody directed against the erythrocytic B-G antigens of the major histocompatibility complex (MHC) of the chicken, an antiserum raised against purified erythrocytic B-G protein, and a cDNA probe from the BeckmanB-G subregion were used to look for evidence of the expression ofB-G genes in tissues other than blood. Evidence has been found in northern hybridizations, in immunoblots, and in immunolabeled cryosections for the presence of B-G-like antigens in the duodenal and caecal epithelia. Additional B-G-like molecules may be expressed in the liver as well. The BG-like molecules in these tissues appear larger and somewhat more heterogeneous than the B-G antigens expressed on erythrocytes. Further characterization of these newly recognized B-G-like molecules may help to define a function for the enigmatic B-G antigens of the MHC. al. 1977; Miller et al. 1982, 1984; Salomonsen et al. 1987; Kline et al. 1988), and in the multiplicity of B-G restriction fragment patterns found in genomic DNA from different haplotypes (Goto et al. 1988; Miller et al. 1988; Chausse et al. 1989). The B-G antigens have contributed, together with the B-F (class I) and B-L (class II) antigens, to the definition of over 27 B system haplotypes in experimental flocks (Briles et al. 1982). Yet the function of the B-G antigens remains entirely unknown. No mammalian counterparts have been identified, although the possibility remains that there may be similar antigens among the blood group systems of mammals. In an effort to define a function of the B-G antigens, a recently cloned B-G sequence (Miller et al. 1988; Goto et al. 1988) and antibodies to the B-G polypeptides (Miller et al. 1982, 1984) were used to examine other tissues for evidence of B-G expression.

The human genes for the alpha and gamma subunits of the mast cell receptor for immunoglobulin E are located on human chromosome band 1q23.

Abstract: The receptor with high affinity for immunoglobulin E (FcERI) is a key molecule in triggering the allergic reaction. It isα tetrameric complex of oneα subunit, oneβ subunit, and two disulfide-linkedγ subunits. This receptor is present exclusively on mast cells and basophils. Molecules identical to theγ subunit of FceRI also formα cell surface complex with other Fc receptors such as mouse FcγRIIa in macrophages and most probably with human FcγRIII (CD16) in natural killer (NK) cells. Here we show by in situ hybridization that the human genes for theα (FCER1A) and γ subunits (FCER1 G) of FcERI and the gene for FcγRIII (FCGR3, CD16) are located on human chromosome band 1823.

Class II genes of miniature swine. III. Characterization of an expressed pig class II gene homologous to HLA-DQA.

Abstract: This report presents an analysis of the SLA-DQA gene organization, the isolation of two SLA-DQA allelic cDNA clones, as well as sequence comparisons between the SLA-DQA clones and other DQA-related genes

The transport of class I major histocompatibility complex antigens is determined by sequences in the α1 and α2 protein domains

Abstract: The transport of human-mouse hybrid class I histocompatibility antigens has been studied in a mutant human cell line, 174 X CEM.T2 (T2). T2, a somatic cell hybrid of human B- and T-lymphoblastoid cell lines (B-LCL and T-LCL, respectively), synthesized HLA-A2 and HLA-B5 glycoproteins, but expresses only low levels of A2 and undetectable levels of B5 at the cell surface. We have previously shown that the products of human class I genes introduced into T2 by transfection behave like the endogenous HLA-B5 glycoproteins, while the products of mouse class I alleles similarly introduced are transported normally to the cell surface. We have now determined that the surface expression of class I glycoproteins in T2 depends on the origin of the alpha 1 and alpha 2 domains. Human (HLA-B7) and mouse (H-2Dp) hybrid class I genes, encoding the leader, alpha 1, and alpha 2 sequences of one species fused to the alpha 3, transmembrane, and cytoplasmic domains of the other, were transfected into T2. Normal surface expression of the hybrid class I molecule was observed in T2 only when the leader, alpha 1, and alpha 2-encoding exons were derived from the mouse gene. The reciprocal construct, encoding human leader, alpha 1, and alpha 2 domains fused to the mouse alpha 3, transmembrane, and cytoplasmic regions, resulted in biosynthesis of a hybrid glycoprotein which was not transported to the cell surface. The products of both constructs were expressed normally in control cells. The effects of glycosylation on class I antigen transport were also studied using mutant class I constructs with altered glycosylation sites. Two mutant B7 genes encoding either an extra glycosylation site at position 176 or no glycosylation sites were transfected into T2. These mutant products were expressed at the cell surface in control cells, but were synthesized and not surface-expressed in T2. These data demonstrate that the HLA/H-2 transport dichotomy in T2 is a function of the origin of the alpha 1 and/or alpha 2 domains of the class I glycoprotein, and is not a reflection of glycosylation differences between the human and mouse molecules.

Einfαsup k transgene in B10 mice suppresses the development of myasthenia gravis

Abstract: Mice bearing the H-2 bhaplotype are susceptible to the development of experimental autoimmune myasthenia gravis (EAMG), induced by acetylcholine receptor (AChR) autoimmunity. One of the genes influencing EAMG susceptibility has been mapped to the A blocus of the major histocompatibility complex, and the Aβ chain has been implicated in the pathogenesis. Mice of the H-2 bhaplotype, including C57BL/10 (B10), have a genomic deletion of the E αgene and therefore fail to express the E molecule on their cell surface. To test the hypothesis that failure to express the cell surface E molecule in B10 mice contributes to EAMG pathogenesis, E infα sup transgenic B10 mice expressing the T molecule were examined. Expression of the E molecule in E infα sup transgenic B10 mice partially prevented the development of EAMG.

Complexity at the mouse minor histocompatibility locus H-4.

Abstract: The fine immunogenetics of the chromosome 7 mouse minor histocompatibility (H) locusH-4 was investigated. Both class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) and class II MHC-restricted “helper” T cells (TH) specifically reactive with H-4 antigens were isolated as clones and were used as genetic probes for classical backcross segregation analysis. Results of a four point cross indicated that theH-4 locus was actually comprised of two genes, that have been designatedH-46 andH-47. The former encodes antigens recognized by the TH and the latter encodes antigens recognized by the CTL. Moreover, these two genes could be separated from the gene pink-eyed dilution (p) which was found to be “sandwiched” between them. The functional significance of a minor H congenic strain differing by both TH-definedH-46 and CTL-definedH-47 was addressed using F1 complementation tests. Such studies indicated that immune responses against H-46 antigens was required for generation of H-47-specific CTL. Altogether, these results suggest selective presentation of different minor H gene products by class I or class II MHC proteins and that the minor H “locus”H-4 may have necessarily included both TH and CTL-defined genes because of requisite TH-CTL collaboration.

Localization of a mouse heat shock Hsp70 gene within the H-2 complex

Abstract: The major heat shock protein (HSP70) is a member of a multigene family which is conserved among different species (Pelham 1986). In humans, a duplicated locus encoding HSP70 was recently mapped within the class III region of the major histocompatibility complex (MHC), HLA (Sargent et al. 1989). Similarly, HSP70 genes are located in the rat MHC (Wurst et al. 1989) and the goat MHC (Cameron et al. 1990). It is well documented that numerous autoimmune diseases such as insulin-dependent diabetes mellitus (IDDM) in humans are frequently associated with particular MHC haplotypes (reviewed in Todd et al. 1988). Several studies have demonstrated a significant association of disease susceptibility with certain class II DQ and DR alleles in diabetic patients (Stetler et al. 1985; Henson et al. 1987; Thomson 1988). Similarly, spontaneous autoimmune diabetes in the nonobese diabetic (NOD) mouse, a model for IDDM, is controlled in a recessive fashion by multiple genes including one locus or a gene complex (Idd-1 s) linked with H-2 on chromosome 17 (Chr 17; Hattori et al. 1986; Prochazka et al. 1987). Studies of the H-2 haplotype in NOD have indicated that the unique Ab gene (homologous to DQ) and the lack of Ea (homologous to DR) expression are significant diabetogenic determinants in this model (reviewed in Leiter 1989). However, neither the identity nor the precise position of Idd-1 s are known and it is possible that combinations of particular alleles of MHC class I, II, and/or III loci may be critical in determining the susceptible haplotype (Leiter 1989). According to HSP70 characteristics (stress-protective role in cells, homology with antigens of some pathogenic microorganisms, position of the structural gene within the class III region of HLA), this protein may play a role in the association of some MHC haplotypes with autoimmunity (Sargent et al. 1989). As a basis for understanding possible relationships between HSP70 and other