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Group Antigens (group + antigen)
Kinds of Group Antigens Selected AbstractsEvidence of Immune Tolerance to Blood Group Antigens in a Case of ABO-Incompatible Pediatric Liver TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2007H. Ohdan In a 12-year-old patient with blood group O, who had received a partial liver graft 10 years ago from his father with blood group A, the levels of anti-A-specific antibodies (Abs) were persistently undetectable after the transplantation, while the levels of anti-B-specific Abs gradually increased and attained a plateau. Peripheral blood mononuclear cells (PBMCs) from this patient were engrafted into NOD/SCID mouse in order to investigate the immune response to donor-type blood group antigens. Even after sensitization with blood group-A erythrocytes, no anti-A Abs were detected in the serum samples of the mouse that received PBMCs from the blood group-O recipient of group-A liver allograft, however, immunoglobulins specific for antigens other than the A antigens were produced. Thus, we provide a possible evidence of immune tolerance to blood group antigens in this ABO-incompatible pediatric liver transplantation. [source] Two generations with familial thrombotic thrombocytopenic purpuraINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 1 2006R. G. Rodrigues Summary Thrombotic thrombocytopenic purpura (TTP) is a rare multi-system disease characterised by the pentad of microangiopathic haemolytic anaemia, thrombocytopenia, renal dysfunction, fever and neurologic changes. A hereditary form of recurrent familial TTP has been described, which usually presents in adolescence or early adulthood and can lead to recurrent or chronic relapsing TTP. Genetic analyses of patients with familial TTP have linked the disease to chromosome 9q34, and an increased incidence is seen in people with HLA-B40 group antigens. We describe here an 11-year-old Egyptian girl with no significant past medical history who presented with new onset of bruising, petechial rash, fatigue and fevers and was diagnosed with familial TTP. Further testing revealed that both the patient and her father had the HLA-B40 group antigen and also had ADAMTS-13 von Willebrand factor-cleaving protease deficiency as well as factor-H deficiency. [source] Haemolytic uraemic syndrome: prognostic factorsINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1 2000D. A. Green Haemolytic uraemic syndrome (HUS) associated with Escherichia coli O157:H7 is the commonest cause of acute renal failure (ARF) in childhood. Production of verotoxin by the organism is pivotal in the pathogenesis of the disease. Verotoxin binds to a receptor on blood and endothelial cells, expressed as the P1 blood group antigen on red blood cells. A protective effect of the P1 phenotype has been proposed in this disease. This study investigates prognostic factors and the relationship between outcome and P1 phenotype in 27 cases of diarrhoea-associated HUS. A poor outcome as defined by the presence of chronic renal failure (CRF), hypertension or proteinuria on 6 month follow-up was associated with the age of the patient at presentation and with the following clinical markers: maximum WBC and duration of raised WBC, duration of anuria and duration of need for dialysis. None of these outcome measures or prognostic factors, and no extra-renal manifestations of the disease were associated with P1 phenotype. [source] Prevention of red cell alloimmunization by CD25 regulatory T cells in mouse modelsAMERICAN JOURNAL OF HEMATOLOGY, Issue 8 2007Jin Yu Transfusion therapy is currently an effective therapeutic intervention in a number of diseases, including sickle cell disease. However, its use is complicated by a high incidence of red blood cell (RBC) alloimmunization in the transfusion recipients. The identification of T regulatory cells (Tregs) among the CD4+ CD25+ T cell subset as key regulators of peripheral tolerance in mice as well as humans has opened an exciting era in the prevention and treatment of autoimmune disease and for improving organ transplantation. However, their potential in inducing transfusion tolerance remains to be explored. We used red cells from mice transgenic for human glycophorin A blood group antigen as donor cells and transfused wild-type mice to induce alloantibodies, as an experimental system to study RBC alloimmunization. We found that depletion with anti-CD25 enhanced the alloantibody production, indicating that CD25 Tregs play an important role in regulation of alloantibody responses. More importantly, adoptive transfer of purified population of CD4+CD25+ but not CD4+CD25, cells from naïve mice prevented the induction of IgG and IgM alloantibody production in transfusion recipients, with a concomitant reduction in activated splenic B cells and macrophages. Similarly, adoptive transfer of purified populations of CD4+CD25+ cells from naïve mice into naïve syngeneic recipients inhibited the anti-Ig response to rat RBCs in the recipients but transfer of control CD4+CD25, cells did not. Altogether, our results demonstrate that Tregs participate in the control of transfusion-associated RBC alloantibody responses, opening up the possibility that Treg immunotherapy may be exploited for suppressing transfusion immunization events. Am. J. Hematol., 2007. © 2007 Wiley-Liss, Inc. [source] Isolation of a porcine UDP-GalNAc transferase cDNA mapping to the region of the blood group EAA locus on pig chromosome 1ANIMAL GENETICS, Issue 3 2001E. Meijerink In our studies of the genes constituting the porcine A0 blood group system, we have characterized a cDNA, encoding an ,(1,3)N-acetylgalactosaminyltransferase, that putatively represents the blood group A transferase gene. The cDNA has a 1095-bp open reading frame and shares 76.9% nucleotide and 66.7% amino acid identity with the human ABO gene. Using a somatic cell hybrid panel, the cDNA was assigned to the q arm of pig chromosome 1, in the region of the erythrocyte antigen A locus (EAA), which represents the porcine blood group A transferase gene. The RNA corresponding to our cDNA was expressed in the small intestinal mucosae of pigs possessing EAA activity, whereas expression was absent in animals lacking this blood group antigen. The UDP-N-acetylgalactosamine (UDP-GalNAc) transferase activity of the gene product, expressed in Chinese hamster ovary (CHO) cells, was specific for the acceptor fucosyl- ,(1,2)galactopyranoside; the enzyme did not use phenyl- , - D -galactopyranoside (phenyl- , -D-Gal) as an acceptor. Because the ,(1,3)GalNAc transferase gene product requires an ,(1,2)fucosylated acceptor for UDP-GalNAc transferase activity, the ,(1,2)fucosyltransferase gene product is necessary for the functioning of the ,(1,3)GalNAc transferase gene product. This mechanism underlies the epistatic effect of the porcine S locus on expression of the blood group A antigen. Abbreviations: CDS: coding sequence; CHO: Chinese Hamster Ovary; EAA: erythrocyte antigen A; FCS: foetal calf serum; Fuc,(1,2)Gal: fucosyl- ,(1,2)galactopyranoside; Gal: galactopyranoside; GGTA1: Gal,(1,3)Gal transferase; PCR: polymerase chain reaction; phenyl- , -D-Gal: phenyl- , - D -galactopyranoside; R: Gal,1-4Glc,1-1Cer; UDP-GalNAc: uridine diphosphate N-acetylgalactosamine [source] Clonogenicity, gene expression and phenotype during neutrophil versus erythroid differentiation of cytokine-stimulated CD34+ human marrow cells in vitroBRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2004Louise Edvardsson Summary With the objective to correlate clonogenicity, gene expression and phenotype during differentiation, human bone marrow CD34+ cells were cultured in vitro to stimulate erythroid or neutrophil development, and sorted into five subpopulations according to their surface expression of CD15/CD33 and blood group antigen A/CD117 respectively. Sorted cells were cultured in methylcellulose and analysed by real-time reverse transcription polymerase chain reaction for expression of neutrophil and erythroid marker genes. Surface expression of CD15 coincided with restriction to neutrophil/monocyte differentiation and A antigen with restriction to erythroid differentiation. GATA-2 mRNA was down-regulated during both neutrophil and erythroid maturation, whereas GATA-1, SCL, ABO, erythropoietin receptor, Kell, glycophorin A, , -globin and , -haemoglobin stabilizing protein were up-regulated during erythroid differentiation and silenced during neutrophil differentiation. CCAAT/enhancer-binding protein (C/EBP)- ,, PU.1, granulocyte colony-stimulating factor receptor, PR3, C/EBP- , and lactoferrin were sequentially expressed during neutrophil differentiation but rapidly down-regulated during the early erythroid stages. Nuclear factor erythroid-derived 2 (NF-E2) and glycophorin C were expressed both during neutrophil and erythroid differentiation. Our data support the notion of early expression of several lineage-associated genes prior to actual lineage commitment, defined by surface expression of CD15 and A antigen as markers for definitive neutrophil/monocyte and erythroid differentiation respectively. Previous findings, primarily from cell lines and mouse models, have been extended to adult human haematopoiesis. [source] Aly/,REF, a factor for mRNA transport, activates RH gene promoter functionFEBS JOURNAL, Issue 11 2005Hiroshi Suganuma The rhesus (Rh) blood group antigens are of considerable importance in transfusion medicine as well as in newborn or autoimmune hemolytic diseases due to their high antigenicity. We identified a major DNaseI hypersensitive site at the 5, flanking regions of both RHD and RHCE exon 1. A 34 bp fragment located at ,191 to ,158 from a translation start position, and containing the TCCCCTCCC sequence, was involved in enhancing promoter activity, which was assessed by luciferase reporter gene assay. A biotin-labelled 34 bp probe isolated an mRNA transporter protein, Aly/REF. The specific binding of Aly/REF to RH promoter in erythroid was confirmed by chromatin immunoprecipitation assay. The silencing of Aly/REF by siRNA reduced not only the RH promoter activity of the reporter gene but also transcription from the native genome. These facts provide second proof of Aly/REF as a transcription coactivator, initially identified as a coactivator for the TCR, enhancer function. Aly/REF might be a novel transcription cofactor for erythroid-specific genes. [source] Role of Mucin Lewis Status in Resistance to Helicobacter pylori Infection in Pediatric PatientsHELICOBACTER, Issue 4 2010Sara Lindén Abstract Background:,Helicobacter pylori causes gastritis, peptic ulcer and is a risk factor for adenocarcinoma and lymphoma of the stomach. Gastric mucins, carrying highly diverse carbohydrate structures, present functional binding sites for H. pylori and may play a role in pathogenesis. However, little information is available regarding gastric mucin in children with and without stomach diseases. Materials and Methods:, Expression of mucins and glycosylation was studied by immunohistochemistry on gastric biopsies from 51 children with and without H. pylori infection and/or peptic ulcer disease. Results:, In all children, MUC5AC was present in the surface epithelium and MUC6 in the glands. No MUC6 in the surface epithelium or MUC2 was detected in any section. The Leb and Lea blood group antigens were present in the surface epithelium of 80% and 29% of children, respectively. H. pylori load was higher in Leb negative children than in Leb positive individuals (mean ± SEM 17.8 ± 3.5 vs 10.8 ± 1.5; p < 0.05), but there was no correlation between Lea or Leb status and gastritis, nodularity, and gastric or duodenal ulcer (DU). Expression of sialyl-Lex was associated with H. pylori infection, and DU. Conclusions:, Mucin expression and glycosylation is similar in children and adults. However, in contrast to adults, pediatric H. pylori infection is not accompanied by aberrant expression of MUC6 or MUC2. Furthermore, the lower H. pylori density in Leb positive children indicates that H. pylori is suppressed in the presence of gastric mucins decorated with Leb, the binding site of the H. pylori BabA adhesin. [source] Two generations with familial thrombotic thrombocytopenic purpuraINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 1 2006R. G. Rodrigues Summary Thrombotic thrombocytopenic purpura (TTP) is a rare multi-system disease characterised by the pentad of microangiopathic haemolytic anaemia, thrombocytopenia, renal dysfunction, fever and neurologic changes. A hereditary form of recurrent familial TTP has been described, which usually presents in adolescence or early adulthood and can lead to recurrent or chronic relapsing TTP. Genetic analyses of patients with familial TTP have linked the disease to chromosome 9q34, and an increased incidence is seen in people with HLA-B40 group antigens. We describe here an 11-year-old Egyptian girl with no significant past medical history who presented with new onset of bruising, petechial rash, fatigue and fevers and was diagnosed with familial TTP. Further testing revealed that both the patient and her father had the HLA-B40 group antigen and also had ADAMTS-13 von Willebrand factor-cleaving protease deficiency as well as factor-H deficiency. [source] Blood group antigens and immune responses,detailed knowledge is necessary to prevent immunization and to follow up immunized individualsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010A. Husebekk Background The immune system is educated to detect and react with foreign antigens and to tolerate self-antigen. Transfusion of blood cells and plasma and pregnancies challenge the immune system by the introduction of foreign antigens. The antigens may cause an immune response, but in many instances this is not the case and the individual is not immunised after exposure of blood group antigens. Aims The aim of the presentation is to dissect some immune responses to blood group antigens in order to understand the mechanism of immunisation. Methods The results of immune responses to blood group antigens can be detected by the presence of antibodies to the antigens. If the antibodies are of IgG class, the activated B cells have received help from antigen specific T cells. Both antibodies, B cells and T cells can be isolated from immunised individuals and studied in the laboratory. Also B-cell receptors and T-cell receptors as well as MHC molecules on antigen presenting cells can be studied and models of the immune synapses can be created in vitro. Results The most classic immune responses in transfusion medicine and in incompatible pregnancies are immune responses to the RhD antigen on red cells, HLA class I molecules on white cells and platelets and human platelet antigens. The nature of these antigens are different; RhD antigens are part of a large complex, present on red cells from RhD positive individuals and completely lacking on red cells from RhD negative individuals. It is likely that many peptides derived from this antigen complex may stimulate T cells and B cells. HLA antigens are highly polymorphic and the antigens are known to induce strong alloimmune responses. The HPA antigens are created by one amino acid difference in allotypes based on a single nucleotide polymorphism at the genetic level. HPA 1a induce immune responses in 10% of HPA 1b homozygote pregnant women. The result of these immune responses is destruction of blood cells with clinical consequences connected to the effect of transfusions or the outcome of pregnancies. Summary/Conclusions Even though there is emerging knowledge about the immune responses to some of the blood group antigens, more information must be gained in order to understand the complete picture. The action of the innate immune response initiating the adaptive immune response to blood group antigens is not well understood. A detailed understanding of both the innate ad the adaptive part of the immune response is necessary to identify individuals at risk for immunisation and to prevent immunisation to blood group antigens. [source] Effect of blood group on idiopathic thrombotic thrombocytopenic purpuraJOURNAL OF CLINICAL APHERESIS, Issue 4 2009Lara Zuberi Abstract Thrombotic thrombocytopenic purpura (TTP) is a condition caused by deficiency of ADAMTS13 resulting in accumulation of ultra large Von Willebrand factor multimers (ULVWF), leading to micro thrombi in multiple organs. The varying susceptibilities of blood group antigens to ADAMTS13 have been demonstrated. A and B antigens are protective of VWF; and VWF purified from blood group O individuals has been shown to be cleaved faster by ADAMTS13 compared to VWF from blood group AB individuals. We proposed that there may be a difference in the incidence of blood groups in TTP patients compared with the general population. We felt this to be important for a life-threatening disease with poorly understood epidemiology. We report a retrospective analysis of 74 patients presenting from 1993 to 2008 with idiopathic TTP. We studied the incidence across various blood groups and also estimated the recurrence and mortality in each group. The incidence of various blood groups were as follows: O 36%, A 36%, B 25%, and AB 2%, compared with expected frequencies in the Detroit area: O 44%, A 33% B 20%, and AB 3%. There was a trend of lower than expected frequency of blood group O. There were 24 recurrences and 14 deaths, uniform across blood groups. We hypothesized that there may be an association between blood groups and the risk of TTP; however the differences in our study were not statistically significant. Recurrence and disease specific mortality did not appear to be impacted by blood group. J. Clin. Apheresis 2009. © 2009 Wiley-Liss, Inc. [source] Association of peptic ulcer with increased expression of Lewis antigens, but not vacuolating cytotoxin activity or babA2 gene status, in Helicobacter pylori strains from ChinaJOURNAL OF DIGESTIVE DISEASES, Issue 1 2006Peng Yuan ZHENG OBJECTIVE: Controversies exist regarding the virulence factors, such as vacA, babA2 and Lewis blood group antigens, of Western and Asian strains of Helicobacter pylori. The aim of the present study was to determine the significance of these potential virulence factors in the Chinese population. METHODS: Seventy-two strains of H. pylori isolated from patients in Zhengzhou, China, including 43 cases of peptic ulcer (PU) and 29 cases of chronic gastritis, were determined. Vacuolating cytotoxin assay was performed by HeLa cells. The expression of Le blood group antigens (Lea, Leb, Lex and Ley) was performed by enzyme-linked immunosorbent assay (ELISA). babA2 gene was identified by polymerase chain reaction. Frequencies were compared using two-tailed Fisher's exact test. Cytotoxin activities were compared using Spearman's rank correction test. RESULTS: Vacuolating cytotoxin activity was detected in 61 of the 72 strains (84.7%), but there was no significant difference in vacuolating cytotoxin activity (83.7% vs 86.2%, P = 0.821) or titer (4.4 ± 3.8 vs 4.2 ± 4.1, P = 0.876) between the PU and gastritis strains. Significantly more PU strains expressed two or more Lewis antigens (Lex, Ley, Lea or Leb) than strains from the chronic gastritis patients (90.7% vs 65.5%, P = 0.029). Of the 43 strains from PU patients, 17 (39.5%) were positive for babA2, compared with 11 (38.5%) of the 29 strains from gastritis patients (P = 0.924). There was no significant difference in the vacuolating cytotoxin activity or titer between strains expressing two or more Lewis antigens and less than two antigens (84.5% vs 85.7%, P = 1.000; 4.4 ± 4.2 vs 4.3 ± 3.2, P = 0.965). Of the 72 H. pylori strains, 28 were babA2 positive, of which 24 were cytotoxic, compared with 37 of 44 babA2-negative strains (P = 1.000). CONCLUSION: The present study suggests that PU is associated with increased Lewis antigen expression, but not vacuolating cytotoxin production or the presence of babA2, in the H. pylori strains in the Chinese population. [source] Titres of naturally occurring alloantibodies against feline blood group antigens in Turkish Van catsJOURNAL OF SMALL ANIMAL PRACTICE, Issue 6 2004S. Arikan Seventy-eight Turkish Van cats were examined for alloantibody titres, of which 42·3 per cent had type A blood and 57·7 per cent had type B blood. No type AB cats were found. All type B cats (n=45) showed gross evidence of agglutinating anti-A antibody, with titres ranging from 2 to 256. Sixty-seven per cent of type B cats had anti-A antibody in their plasma, with titres ranging from 8 to 32. However, 13 per cent of type B cats had plasma alloantibody titres of less than 8 and 20 per cent had titres that were higher than 32. A total of 33 type A cats were also tested for anti-B alloantibody titres in their plasma. Among the type A plasma, gross agglutination at titres of 2 and greater than 2 were determined in 24 per cent and 36 per cent of samples, respectively. Microscopic agglutination was seen in an additional 18 per cent of plasma samples. There was no significant association between gender and plasma alloantibody titres of cats (P>0·05). [source] Norovirus binds to blood group A-like antigens in oyster gastrointestinal cellsLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2006P. Tian Abstract Aims:, To determine if histo-blood group antigens (HBGA) present in oyster gastrointestinal (GI) cells mediate accumulation of human noroviruses (NoV) in oyster GI cells. Methods and Results:, HBGA-specific monoclonal antibodies (MAbs) were used to determine the presence of the corresponding HBGA in oyster GI cells. All oyster samples tested contained type A-like HBGA in GI tissue as measured by ELISA. Recombinant Norwalk virus viral like particles (rNVLP) were bound to plates coated with oyster GI homogenate. The binding was inhibited when rNVLPs were pre-incubated with MAbs specific for type A HBGA, or samples of human saliva from type A individuals. Co-localization of rNVLP and type A-like HBGA, but not type B-like or type H-like HBGA, on GI epithelial cells was observed by immunofluorescent histochemical staining and three-channel confocal scanning laser microscopy. Conclusion:, Type A-like HBGA is present in oyster GI cells and responsible for binding of rNVLP. Significance and Impact of the Study:, This is the first report of the presence of type A-like HBGA in oyster GI cells and the specific binding of rNVLP to type A-like HBGA on oyster GI cells. The results of this study suggest that human NoV concentrate in oyster GI cells by specific binding to concentrated type A-like HBGA rather than by a nonmolecular entrapment within the tissues. [source] Equivalent Outcomes for Pediatric Heart Transplantation Recipients: ABO-Blood Group Incompatible versus ABO-CompatibleAMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2010A. I. Dipchand ABO-blood group incompatible infant heart transplantation has had excellent short-term outcomes. Uncertainties about long-term outcomes have been a barrier to the adoption of this strategy worldwide. We report a nonrandomized comparison of clinical outcomes over 10 years of the largest cohort of ABO-incompatible recipients. ABO-incompatible (n = 35) and ABO-compatible (n = 45) infant heart transplantation recipients (,14 months old, 1996,2006) showed no important differences in pretransplantation characteristics. There was no difference in incidence of and time to moderate acute cellular rejection. Despite either the presence (seven patients) or development (eight patients) of donor-specific antibodies against blood group antigens, in only two ABO-incompatible patients were these antibodies implicated in antibody-mediated rejection (which occurred early posttransplantation, was easily managed and did not recur in follow-up). Occurrence of graft vasculopathy (11%), malignancy (11%) and freedom from severe renal dysfunction were identical in both groups. Survival was identical (74% at 7 years posttransplantation). ABO-blood group incompatible heart transplantation has excellent outcomes that are indistinguishable from those of the ABO-compatible population and there is no clinical justification for withholding this lifesaving strategy from all infants listed for heart transplantation. Further studies into observed differing responses in the development of donor-specific isohemagglutinins and the implications for graft accommodation are warranted. [source] Absence of Donor-Specific Anti-HLA Antibodies After ABO-Incompatible Heart Transplantation in Infancy: Altered Immunity or Age?AMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2010S. Urschel Specific B-cell tolerance toward donor blood group antigens develops in infants after ABO-incompatible heart transplantation, whereas their immune response toward protein antigens such as HLA has not been investigated. We assessed de novo HLA-antibodies in 122 patients after pediatric thoracic transplantation (28 ABO-incompatible) and 36 controls. Median age at transplantation was 1.7 years (1 day to 17.8 year) and samples were collected at median 3.48 years after transplantation. Antibodies were detected against HLA-class I in 21 patients (17.2%), class II in 18 (14.8%) and against both classes in 10 (8.2%). Using single-antigen beads, donor-specific antibodies (DSAs) were identified in six patients (all class II, one additional class I). Patients with DSAs were significantly older at time of transplantation. In patients who had undergone pretransplant cardiac surgeries, class II antibodies were more frequent, although use of homografts or mechanical heart support had no influence. DSAs were absent in ABO-incompatible recipients and class II antibodies were significantly less frequent than in children with ABO-compatible transplants. This difference was present also when comparing only children transplanted below 2 years of age. Therefore, tolerance toward the donor blood group appears to be associated with an altered response to HLA beyond age-related effects. [source] Evidence of Immune Tolerance to Blood Group Antigens in a Case of ABO-Incompatible Pediatric Liver TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2007H. Ohdan In a 12-year-old patient with blood group O, who had received a partial liver graft 10 years ago from his father with blood group A, the levels of anti-A-specific antibodies (Abs) were persistently undetectable after the transplantation, while the levels of anti-B-specific Abs gradually increased and attained a plateau. Peripheral blood mononuclear cells (PBMCs) from this patient were engrafted into NOD/SCID mouse in order to investigate the immune response to donor-type blood group antigens. Even after sensitization with blood group-A erythrocytes, no anti-A Abs were detected in the serum samples of the mouse that received PBMCs from the blood group-O recipient of group-A liver allograft, however, immunoglobulins specific for antigens other than the A antigens were produced. Thus, we provide a possible evidence of immune tolerance to blood group antigens in this ABO-incompatible pediatric liver transplantation. [source] LAMPs and ABH histo-blood group antigens in granulation tissue,APMIS, Issue 6 2007VICTORIA S. SARAFIAN Endothelial cells are major participants in angiogenic processes accompanying wound repair. The functions of ABH histo-blood group antigens (HBGAs) and lysosome-associated membrane proteins LAMP-1 and LAMP-2 in endothelial cells of granulation tissue are currently unkown. Here we hypothesize that HBGAs and LAMPs enrich the phenotypic characteristics of endothelial cells and might be implicated in the plasticity of granulation tissue. Immunohistochemistry revealed permanent expression of HBGAs in the cytoplasm of endothelial cells of all sprouting capillaries regardless of the organ examined. A modulation in both the localization and the intensity of the signal for LAMPs was observed. Interestingly, LAMP-1 showed a more intensive staining compared to LAMP-2. LAMP-1 was found in the cytoplasm, as well as on plasma membranes of endothelial cells. We present the first comparative immunohistochemical study of the expression of HBGA and LAMPs in endothelial cells of granulation tissue. Novel evidence for modulating LAMP reactivity is reported. Our results suggest that both glycoconjugates might contribute to the process of neoangiogenesis and tissue remodeling in wound healing. [source] Modulation of ABH histo-blood group antigen expression in normal and myasthenic human thymus,APMIS, Issue 10 2006VICTORIA S. SARAFIAN The role of ABH histo-blood group antigens (HBGA) in intercellular communication during normal and pathological processes is still uncertain. The present work investigates the expression of ABH HBGA in epithelial cells and lymphocytes in normal thymus, and characterizes the modulation of their immunoreactivity during myasthenic transformation. Immunohistochemistry and immunoelectron microscopy were applied on normal young thymus and on myasthenia gravis-associated thymomas and thymic hyperplasias. The Hassall's corpuscules in the thymus of young individuals were homogeneously stained for HBGA, while in hyperplastic glands only their central part was positive. Stromal epithelial cells permanently expressed HBGA in all tissue samples. In thymomas, mainly the lymphocytes in close proximity to antigen expressing epithelial cells were positive, while in the hyperplastic gland the most intensely stained lymphocytes were those within Hassall's corpuscules. Novel evidence for modulation of ABH antigen reactivity in normal and myasthenic human thymus is presented. It suggests that HBGA might participate in the regulation of the cross-talk in the thymocyte microenvironment throughout the ontogeny, as well as during the myasthenic transformation. [source] ABH and Lewis histo-blood group antigens in cancerAPMIS, Issue 1 2001JACQUES LE PENDU Antigens of the ABH and Lewis histo-blood group family can be found on many normal cells, mainly of epithelial type. In carcinomas, altered expression of the various carbohydrate epitopes of this family occur, and are often strongly associated with either a good or bad prognosis. A review of the available data on these tumor-associated markers, their biosynthesis and their prognostic value is proposed here. For a long time it has been unclear whether their presence could affect the behavior of carcinoma cells. Recent data, however, indicate that they play biological roles in the course of tumor progression. The presence of sialyl-Lea or sialyl-Lex, which are ligands for selectins, promotes the metastatic process by facilitating interaction with the endothelium of distant organs. The loss of A and B antigens increases cellular motility, while the presence of H epitopes increases resistance to apoptosis by mechanisms that remain to be defined. The Ley antigen has procoagulant and angiogenic activities. All these observations are used to present a model that may account for the described associations between the presence or loss of these markers and the outcome of disease. Finally, their potential clinical applicaitons as tumor-associated markers or as targets of immunotherapy are reviewed. [source] Tissue distribution of histo-blood group antigens.APMIS, Issue 1 2000Vibeke Ravn The introduction of immunohistochemical techniques and monoclonal antibodies to specific carbohydrate epitopes has made it possible to study in detail the tissue distribution of histo-blood group antigens and related carbohydrate structures. The present paper summarizes the available data concerning the histological distribution of histo-blood group antigens and their precursor structures in normal human tissues. Studies performed have concentrated on carbohydrate antigens related to the ABO, Lewis, and TTn blood group systems, i.e. histo-blood group antigens carried by type 1, 2, and 3 chain carrier carbohydrate chains. Histo-blood group antigens are found in most epithelial tissues. Meanwhile, several factors influence the type, the amount, and the histological distribution of histo-blood group antigens, i.e. the ABO, Lewis, and saliva-secretor type of the individual, and the cell-and tissue type. Oligosaccharides with blood-group specificity are synthesized by the stepwise action of specific gene-encoded glycosyltransferases. In general, this stepwise synthesis of histo-blood group antigens correlates with cellular differentiation. The H and the Se genes both encode an ,1,2fucosyltransferase, which is responsible for the synthesis of blood group antigen H from precursor disaccharides. A new model for the participation of the Se/H-gene-encoded glycosyl transferases in synthesis of terminal histo-blood group antigens in human tissues is proposed; the type and degree of differentiation rather than the embryologic origin determines whether it is the H or the Se gene-encoded transferases that influence expression of terminal histo-blood group antigens in tissues. 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