H-2g, a glucose analog of blood group H antigen, mediates mononuclear cell recruitment via Src and phosphatidylinositol 3-kinase pathways

OBJECTIVE: Monocyte recruitment by proinflammatory cytokines is a hallmark of rheumatoid arthritis (RA). Lewis(y-6) and H (Le(y)/H) are blood group antigens up-regulated on RA synovial endothelium. We have previously shown that both soluble Le(y)/H and a glucose analog of H, H-2g, are angiogenic and mediateleukocyte-endothelial adhesion via induction of intercellular adhesion molecule 1. We hypothesized that soluble Le(y)/H plays an important role in monocyte recruitment in RA. METHODS: We examined the role of H-2g in monocyte chemotaxis in vitro. We used an RA synovial tissue (ST)-SCID mouse chimera model to evaluate the role of H-2g in monocyte recruitment in vivo. We used Western blots to examine signaling molecules activated by H-2g in monocytes. RESULTS: H-2g induced human monocyte migration in vitro, which was mediated by Src and phosphatidylinositol 3-kinase (PI 3-kinase), since inhibitors and antisense oligodeoxynucleotides (ODNs) of Src and PI 3-kinase significantly decreased H-2g-induced monocyte migration (P < 0.05). H-2g significantly increased mononuclear cell (MNC) homing in vivo into an RA ST-SCID mouse chimera (P < 0.05). Transfection of MNCs with Src antisense ODNs blocked H-2g-induced MNC recruitment into the RA ST-SCID mouse chimera. Additionally, H-2g induced marked phosphorylation of protein kinase CalphaI/betaII (PKCalphaI/betaII), Src, IkappaBalpha, and Akt in monocytes. Src, Akt, and NF-kappaB were shown to be downstream targets of PKCalphaI/betaII, since an inhibitor of PKCalphaI/betaII reduced H-2g-mediated phosphorylation of Src, Akt, and NF-kappaB in monocytes. CONCLUSION: These data suggest that H-2g may be a novel mediator of monocyte recruitment in chronic inflammatory diseases like RA.     

H-2 restriction: Independent recognition of H-2 and foreign antigen by a single receptor

We describe two situations in which the recognition of hapten can compensate for the lack of recognition of appropriate H-2 gene products in hapten-specific, H-2 restricted, T lymphocyte-mediated cytolysis. First, we show that although recognition of appropriate H-2 gene products is essential for the lysis of target cells bearing a low hapten density, significant hapten-specific lysis of H-2 inappropriate target cells is observed at high levels of target cell derivatization. Secondly, we show that hapten-conjugated anti-H-2 antibody inhibits cytolysis poorly even though its binding to target cell H-2 antigens is equivalent to that of underivatized antibody. These results suggest that hapten and H-2 are recognized independently and are therefore inconsistent with the altered-self model. Although our data do not exclude the dual-recognition model, we prefer to interpret them within the framework of a single-receptor model in which hapten and H-2 are recognized independently by receptors of identical idiotype on the T cell. We postulate that the affinity of these receptors for the relevant H-2 gene product is low enough so that the T cell is not activated by encounters with normal-self cells expressing that H-2 gene product. However, when self cells express in addition a foreign antigen that can also be recognized by the same receptor, then the force of T cell-target cell interaction may be increased sufficiently to activate T cell effector function.     

Transporters from H-2b, H-2d, H-2s, H-2k, and H-2g7 (NOD/Lt) haplotype translocate similar sets of peptides.

The TAP complex transports peptides from the cytosol into the lumen of the endoplasmic reticulum for presentation by major histocompatibility complex class I molecules. A limited degree of sequence polymorphism has been observed for the mouse TAP1 and TAP2 genes by restriction fragment length polymorphism and sequence analysis. However, functional polymorphism of the TAP transporter has thus far been observed for the rat only. Here we examine the effect of TAP polymorphism on ATP dependency and peptide specificity of TAP-mediated peptide transport and show that, in the mouse, polymorphism in TAP genes does not measurably alter the function of their gene products. We conclude that TAP polymorphism is unlikely to contribute to the development of autoimmune diseases and that, in the mouse, the specificity of the TAP transporter is matched to that of the F pocket of the class I molecules for which it provides the peptide substrates.     

Molecular cloning, sequence, and expression of a human GDP-L-fucose:beta-D-galactoside 2-alpha-L-fucosyltransferase cDNA that can form the H blood group antigen.

We have previously used a gene-transfer scheme to isolate a human genomic DNA fragment that determines expression of a GDP-L-fucose:beta-D-galactoside 2-alpha-L-fucosyltransferase [alpha(1,2)FT; EC 2.4.1.69]. Although this fragment determined expression of an alpha(1,2)FT whose kinetic properties mirror those of the human H blood group alpha(1,2)FT, their precise nature remained undefined. We describe here the molecular cloning, sequence, and expression of a human cDNA corresponding to these human genomic sequences. When expressed in COS-1 cells, this cDNA directs expression of cell surface H structures and a cognate alpha(1,2)FT activity with properties analogous to the human H blood group alpha(1,2)FT. The cDNA sequence predicts a 365-amino acid polypeptide characteristic of a type II transmembrane glycoprotein with a domain structure analogous to that of other glycosyltransferases but without significant primary sequence similarity to these or other known proteins. To directly demonstrate that the cDNA encodes an alpha(1,2)FT, the COOH-terminal domain predicted to be Golgi-resident was expressed in COS-1 cells as a catalytically active, secreted, and soluble protein A fusion peptide. Southern blot analysis showed that this cDNA identifies DNA sequences syntenic to the human H locus on chromosome 19. These results strongly suggest that this cloned alpha(1,2)FT cDNA represents the product of the human H blood group locus.     

Suppressed expression of blood group B antigen and blood group galactosyltransferase in a preleukemic subject

The B antigen activity was severely diminished in a patient's RBCs at the preleukemic stage prior to chemo- or radiotherapy. The amount of H sites of the patient's RBC membranes was found to be comparable to that of O RBC membranes. The activity of alpha (1----2) fucosyltransferase (H enzyme) was not severely decreased in the patient's plasma and bone marrow. However, the activity of alpha (1----3) galactosyltransferase (B enzyme), which converts H substance to B substance, was drastically reduced in the patient's bone marrow. Thus, the diminished B antigen in the patient's RBCs was caused mainly by the blockage of conversion of the H substance to B substance. It is suggested that the viral oncogene linked to the ABO locus at q34 of chromosome No. 9 would occasionally suppress the expression of blood group A and B enzymes and A and B antigens.     

An acute leukaemia augured before clinical signs by blood group antigen abnormalities and low levels of A and H blood group transferase activities in erythrocytes

A mixed field agglutination pattern with anti-A reagents and very low levels of A and H blood group antigen specific transferase activities were found in the erythrocytes of a 4-year-old girl who presented no clinical signs of haematological disease. Blood and marrow examination displayed some features consistent with a moderate dysmyelopoietic state. 18 months later an acute myeloblastic leukaemia confirmed the suspected haematological malignancy.     

HMT, encoded by H-2M3, is a neoclassical major histocompatibility class I antigen.

H-2M3 encodes HMT, the major histocompatibility complex (MHC) class I heavy chain of the maternally transmitted antigen (Mta). Like classical MHC class I genes, the expression of M3 can be stimulated by gamma-interferon and its message can be detected from mid-gestational embryos (day 8) through adulthood. HMTb, a nonimmunogenic allelic form of HMT, differs from the common HMTa molecule by four amino acids, of which only two (residues 31 and 95) are located in the alpha 1 and alpha 2 domains that form the peptide-binding groove. Recognition of site-directed mutants by Mta-specific cytotoxic T lymphocytes was hardly affected by the substitution of Met for Val31 but was abolished by the substitution of Gln for Leu95, which is located in the beta-sheet floor of the peptide-binding groove. Thus a single amino acid difference is responsible for the immunological silence of HMTb.     

H-2-restricted antigen binding by a hybridoma clone that produces antigen-specific helper factor

Somatic cell hybrids were prepared by fusing the AKR mouse lymphoma BW-5147 with splenic T cells from mice immunized with 4-hydroxy-3-nitrophenylacetic acid (NP) conjugated to chicken serum globulin (CG). From 500 fusion lines 11 were selected on the basis of binding radioiodinated NP-CG. The autoradiographic binding assay was based on previous findings which showed that Lyt-1+ T cells need a lymphokine, lymphocyte-activating factor (LAF), for optimal antigen binding and that they bind preferentially a self-Ia-associated antigen complex, IAC, which is released by adherent cells upon incubation with antigen. Six of the 11 antigen-binding positive lines were tested for helper activity and specific helper factor production in vitro. All of them were found to be positive. One clone was characterized in more detail. It secretes a CG-specific helper factor that contains immunoglobulin heavy chain variable region and I-A determinants. The hybridoma cells bind Ia-containing CG complexes specifically. For binding they need to be treated with LAF, and the binding is restricted to syngenicity in H-2 between the adherent cells used to produce IAC and the antigen-binding hybridoma cells. Regular CG does not bind significantly and does not compete even at high excess with the binding of CG-IAC. These data are interpreted to suggest that the antigen is bound by cells of a clone functional helper T-cell hybridoma line in conjunction with products controlled by H-2I and that the receptor of these cells may have considerably higher affinity for Ia-associated than for regular antigen.     

Structure and expression of a mouse major histocompatibility antigen gene, H-2Ld.

A genomic clone encoding H-2Ld, a mouse major transplantation antigen, has been identified and the structure of the H-2Ld gene has been partially determined. We isolated 35 genomic clones from a BALB/c (H-2d) genomic library by hybridization to mouse or human probes. One of these clones encodes H-2Ld as determined by two criteria. First, the gene encodes a protein that is identical at the 76 known amino acid positions for H-2Ld. Second, when introduced into L cells by DNA-mediated gene transfer, a new H-2 antigen is expressed that is recognized by anti-H-2Ld monoclonal antibodies. The sequence of the H-2Ld protein predicted by the DNA sequences shows more than 80% homology to known H-2 antigens. H-2L-like sequences are found in mutant H-2Kb molecules, suggesting that gene conversion or reciprocal recombination may play a role in the development of H-2 polymorphism.     

Kpa, (Penney), a new antigen in the Kell blood group system

The Kell blood group system has now been complicated by the finding of a new antigen, Penney (Kp^a), and possibly two others (Kp^b and Kp^c). Kp^a is found in about 2 per cent of Bostonians. It is of minor importance clinically because of its infrequency, but has considerable importance in blood typing tests for exclusion of paternity.

Résumé

Un nouvel antigène appartenant au système Kell et désigné Penney (Kp^a) a été découvert, et l'existence de deux autres antigènes (Kp^b et Kp^c) semble possible. Kp^a se trouve chez environ 2% des habitants de Boston. Le nouvel antigène est, au point de vue clinique, d'intérêt médiocre à cause de sa rareté, mais il est important dans les tests sérologiques pour l'exclusion de la paternité

Zusammenfassung

Ein neues, dem Kell-System zugehöriges Blutgruppenantigen Penney (Kp^a) wird beschrieben. Nebst K, k und Kp^a enthält das Kell-System wahrscheinlich noch zwei weitere Antigene, die vorlaufig als Kp^b und Kp^c bezeichnet wurden. Die Häufigkeit von Kp^a beträgt in Boston 2 %. Angesichts der relativen Seltenheit dieses Antigens ist seine klinische Bedeutung gering. Bei Vaterschaftsuntersuchungen hingegen ist dieses Antigen unter Umständen von erheblicher Bedeutung.     

A family in which Ax is transmitted through a person of the blood group A2B

A family is described in which the rare kind of blood known as A_x, A₄, A_z or A_o occurs. The father's phenotype is A_x, that of his son is A₂B and that of the son's daughter is A_x. That an A₂B person can transmit A_x emphasizes our ignorance of the genetic background of this kind of blood.

Résumé

Etude d'une famille dans laqueue plusieurs exemples du groupe rare A_x, dgalement désigné sous le nom de A₄, A_z ou A_o, ont été trouvés. Le phénotype du père est A_x, cdui de son fils est A₂B, et celui de la fille de ce dernier est aussi A_x. Le fait que le groupe A_x se trouve chez la descendante d'une personne du groupe A₂B sert à souligner notre ignorance du mode de transmission du groupe A_x.

Zusammenfassung

Eine Familie, bei welcher die seltene, als A_x, A₄, A_z oder A_o bezeichnete Blutgruppe vorkommt, wird beschrieben. Der Phänotyp des Vaters ist A_x, der seines Sohnes A₂B und derjenige der Tochter dieses Sohnes A_x. Die Tatsache, daß eine Person der Gruppe A₂B A_x übertragen kann, unterstreicht nur unsere mangelnde Kenntnis über die Erbweise dieser Eigenschaft.     

PD-1 deficiency reveals various tissue-specific autoimmunity by H-2b and dose-dependent requirement of H-2g7 for diabetes in NOD mice

Although many autoimmune diseases are associated with particular HLA/H-2 haplotypes, the mechanisms through which specific HLA/H-2 haplotypes afford autoimmune susceptibility remain enigmatic. Here, we analyzed the effects of the diabetes-associated (H-2(g7)) and an antidiabetogenic (H-2(b)) H-2 haplotypes in NOD mice deficient for programmed cell death-1 (PD-1, Pdcd1), a unique model of type 1 diabetes that confers complete penetrance and rapid onset of the disease. NOD-H2(b/b)Pdcd1(-/-) mice were completely protected from diabetes, confirming that H-2(g7) is indispensable for diabetes even in the absence of PD-1. However, NOD-H2(b/b)Pdcd1(-/-) mice developed autoimmune inflammation in multiple tissues including peripheral nerves, stomachs, and exocrine tissues, demonstrating that autoreactive T cells are generated in the context of H-2(b). These autoreactive T cells damaged target tissues only in the absence of PD-1, confirming that PD-1 deficiency unravels the hidden autoimmune susceptibility of the strain by reducing the threshold of T cell activation. Transfer experiments revealed that CD4 T cells are the effector cells of neuritis, and nerve-infiltrating CD4 T cells are strongly deviated toward Th1. Interestingly, neuritogenic T cells were also generated in the context of H-2(g7), in sharp contrast to the strict requirement of H-2(g7) for diabetes. In addition, 60% of the NOD-H2(b/g7)Pdcd1(-/-) mice developed diabetes, suggesting that H-2(b) does not dominantly suppress diabetes and that H-2(g7) induces diabetes in a dose-dependent fashion.     

Amount of H antigen expressed on circulating von Willebrand factor is modified by ABO blood group genotype and is a major determinant of plasma von Willebrand factor antigen levels

To investigate whether the effect of ABO blood group on plasma von Willebrand factor (vWF) levels is mediated by the ABH antigenic determinants carried on N-linked glycans of vWF, we studied 158 group A and group O healthy volunteers. vWF antigen (vWF:Ag) and factor VIII antigen (FVIII:Ag) levels were highest in A(1)A(1) individuals and higher in A(1)O(1) than in A(2)O(1) or O(1)O(1) individuals. Plasma A transferase activity and the amount of A antigen expressed per unit vWF (AvWF) were significantly higher in A(1)A(1) than in A(1)O(1) individuals and higher in A(1)O(1) than in A(2)O(1) individuals. AvWF was correlated strongly with plasma levels of A transferase activity. Thus, we have clearly demonstrated a direct relationship between ABO genotype, A transferase expression, and the amount of A antigen expressed on circulating vWF. H antigen expression per unit vWF (HvWF) was highest in group O individuals. Among group A individuals, the pattern of HvWF expression was A(2)O(1)>A(1)O(1)>A(1)A(1). In group O and group A(2)O(1) individuals, HvWF was inversely correlated with plasma vWF levels. In contrast, among group A(1)A(1) and A(1)O(1) individuals, there was no relationship between AvWF and plasma vWF levels. These findings suggest that it is H antigen expression that mediates the ABO effect on plasma vWF concentration.     

Interrelation between ABH blood group 0, Lewis(B) blood group antigen,Helicobacter pylori infection,and occurrence of peptic ulcer

BACKGROUND: Helicobacter pylori is a human pathogen that causes chronic gastritis and peptic ulcers. Epidemiological studies demonstrated that individuals who are blood group 0 positive or represent non-secretors of their blood group antigens are more likely to develop peptic ulcers. The Lewis(b) blood group antigen has been reported to mediate the attachment of H. pylori to human gastric mucosa. The aim of this study was to examine the interrelation between Le(a-b+) phenotype, blood group 0, H. pylori infection, and peptic ulcer occurrence. PATIENTS AND METHODS: The study population consisted of 330 consecutive patients (185 men, 145 women) referred to endoscopy of the upper gastrointestinal tract for various reasons. AB0(H) blood groups and Lewis(a,b) phenotype were carried out by standard haemagglutination assays. Antibodies (IgG) against H. pylori were determined by a quantitative enzyme-linked immunosorbent assay (ELISA). RESULTS: 49 of the 330 patients (14.8 %) showed duodenal or gastric ulcers with a H. pylori seroprevalence of 87.8 %. The IgG immune response to H. pylori was not dependent on ABH blood group phenotype. There was also no significant association between the secretor status and the presence of H. pylori infection. Secretors, 35/238 (14.7 %), were no more likely to have gastroduodenal ulcer compared with non-secretors, 9/65 (13.8 %). CONCLUSION: Our data show no association between secretor status or specific ABH blood group on the one hand, and H. pylori infection or occurrence of gastroduodenal ulcers on the other. Determination of ABH blood groups or secretor status is, therefore, not a useful tool to characterize the individual risk for gastroduodenal ulcer or to guide any diagnostic procedures.     

Isolation of a cDNA clone for the murine transplantation antigen H-2Kb.

A library of cloned cDNAs constructed from the poly(A)+RNA of the murine thymoma cell line EL4 (b haplotype) was screened with a probe encoding a short region of the H-2Kb transplantation antigen. One of the clones isolated, pH202, contains a region that can code for a transplantation antigen with an amino acid sequence 98% homologous to that previously published for H-2Kb. Based on this high degree of homology, pH202 appears to encode the H-2Kb antigen from amino acid 66 through the carboxy terminus, including 386 nucleotides of 3'-untranslated sequence. The amino acid sequence deduced from pH202 suggests that the H-2Kb antigen is actually 2 amino acids longer than previously reported (a total of 348 residues). Four other differences in amino acid assignments are seen. Analysis of the DNA sequences of pH202 and other H-2 clones previously described in the literature suggests that alternative routes of splicing at the 3' end of the coding region are involved in the production of different transplantation antigen mRNAs.