Summary
New data suggest the involvement of rotavirus (RV) in triggering autoimmunity in coeliac disease (CD) by molecular mimicry between the human‐transglutaminase protein and the dodecapeptide ...(260‐271 aa) of the RV protein VP7 (pVP7). To assess the role of RV in the onset of CD, we measured anti‐pVP7 antibodies in the sera of children with CD and of control groups. We analysed serum samples of 118 biopsy‐proven CD patients and 46 patients with potential CD; 32 children with other gastrointestinal diseases; 107 no‐CD children and 107 blood donors. Using enzyme‐linked immunosorbent assay (ELISA) assay, we measured immunoglobulin (Ig)A–IgG antibodies against the synthetic peptides pVP7, the human transglutaminase‐derived peptide (476–487 aa) which shows a homology with VP7 protein and a control peptide. The triple‐layered RV particles (TLPs) containing the VP7 protein and the double‐layered RV‐particles (DLPs) lacking the VP7 protein were also used as antigens in ELISA assay. Antibody reactivity to the RV‐TLPs was positive in 22 of 118 (18%) CD patients and in both paediatric (17 of 107, 16%) and adult (29 of 107, 27%) control groups, without showing a statistically significant difference among them (P = 0·6, P = 0·1). Biopsy‐proven CD patients as well as the adult control group demonstrated a high positive antibody reactivity against both pVP7 (34 of 118, 29% CD patients; 66 of 107, 62% adult controls) and control synthetic peptides (35 of 118, 30% CD patients; 56 of 107, 52% adult controls), suggesting a non‐specific response against RV pVP7. We show that children with CD do not have higher immune reactivity to RV, thus questioning the molecular mimicry mechanism as a triggering factor of CD.
New data suggest the involvement of rotavirus in triggering autoimmunity in celiac disease by molecular mimicry between the human tissue type 2 transglutaminase protein and a part of the rotavirus related VP7 protein.
The strength of our study lies in its having monitored immunological reactivity to native and well‐characterized viral antigens in the sera of both celiac patients and controls at a young age, very close to a rotavirus infection, without finding any difference in the two study groups.
The data we have gathered fail to support the hypothesis of celiac disease‐autoimmunity induced by mechanisms related to molecular mimicry between the rotavirus‐VP7‐peptide and the human tissue type 2 transglutaminase protein.
A qualidade e a conservação pós-colheita da amora-preta está diretamente relacionadas ao estádio de maturação em que são colhidas. Muitos produtores tem colhido fora do ponto ideal de colheita para ...comercialização e consumo. O objetivo deste trabalho foi avaliar a qualidade físico-química de amoras-pretas ‘Tupy’ sob armazenamento refrigerado, colhidas em diferentes estádios de maturação. Amoras provenientes de um pomar do campo experimental pertencente à Embrapa Clima Temperado, Pelotas-RS, foram colhidas em três estádios de maturação (EM), sendo o estádio de maturação um (EM1) frutas com a epiderme 100% vermelha; estádio de maturação dois (EM2) epiderme 50% vermelha e 50% preta; e estádio de maturação três (EM3) epiderme 100% preta. As amostras foram acondicionadas em embalagens plásticas e armazenadas em câmara fria a temperatura de 4±0,5ºC e umidade relativa de 90-95%, durante 9 dias. As avaliações das frutas foram realizadas aos 0, 3, 6 e 9 dias de armazenamento, quanto ao: teor de sólidos solúveis (SS), pH, acidez titulável (AT), ratio (SS/AT), parâmetros de cor L*, a*, b*, croma, coloração da epiderme (Hue) e perda de massa (PM). As amoras colhidas no EM3 apresentaram o maior conteúdo de SS, menor AT e maior pH. A PM e a AT apresentaram resposta linear crescente e decrescente, respectivamente, ao decorrer do armazenamento. Os parâmetros de cor apresentaram diferenças significativas entre os EM, com tendência a diminuir os valores de L*, a*, b* e croma ao decorrer do amadurecimento. Durante o armazenamento, todos os EM apresentaram mudanças em relação aos parâmetros de cor. O EM3 apresentou a melhor relação SS/AT, assim como reposta linear crescente durante o armazenamento para a mesma. Os EM1 e EM2 apesar de apresentarem alterações em seus parâmetros físico-químicos durante o armazenamento, as mesmas não são suficientes para melhorar o sabor gustativo das frutas. Amoras-pretas colhidas com a epiderme 100% preta (EM3) são as mais adequadas para posterior armazenamento refrigerado.
In this study, we have characterized the early steps of hematopoiesis during embryonic stem cell differentiation. The immunophenotype of hematopoietic progenitor cells derived from murine embryonic ...stem cells was determined using a panel of monoclonal antibodies specific for hematopoietic differentiation antigens. Surprisingly, the CD41 antigen (αIIb integrin, platelet GPIIb), essentially considered to be restricted to megakaryocytes, was found on a large proportion of cells within embryoid bodies although very few megakaryocytes were detected. In clonogenic assays, more than 80% of all progenitors (megakaryocytic, granulo-macrophagic, erythroid and pluripotent) derived from embryoid bodies expressed the CD41 antigen. CD41 was the most reliable marker of early steps of hematopoiesis. However, CD41 remained a differentiation marker because some CD41 â cells from embryoid bodies converted to CD41 + hematopoietic progenitors, whereas the inverse switch was not observed. Immunoprecipitation and western blot analysis confirmed that CD41 was present in cells from embryoid bodies associated with CD61 (β3 integrin, platelet GPIIIa) in a complex. Analysis of CD41 expression during ontogeny revealed that most yolk sac and aorta-gonad-mesonephros hematopoietic progenitor cells were also CD41 + , whereas only a minority of bone marrow and fetal liver hematopoietic progenitors expressed this antigen. Differences in CD34 expression were also observed: hematopoietic progenitor cells from embryoid bodies, yolk sac and aorta-gonad-mesonephros displayed variable levels of CD34, whereas more than 90% of fetal liver and bone marrow progenitor cells were CD34 + . Thus, these results demonstrate that expression of CD41 is associated with early stages of hematopoiesis and is highly regulated during hematopoietic development. Further studies concerning the adhesive properties of hematopoietic cells are required to assess the biological significance of these developmental changes.
We had previously reported, using BY55 monoclonal antibody, a cell surface 80-kDa protein restricted to human functional peripheral blood cytotoxic lymphocytes with either natural killer CD3-or ...cytotoxic T lymphocyte CD3+CD8+phenotype. In the present report, we studied the cytotoxic lymphocytes in adult bone marrow and newborn cord blood as these organs are commonly used as sources of hematological stem cells for allogeneic transplantation. Our results showed that BY55 mAb labeled only 5-10% of the bone marrow lymphocytes, which included a major proportion of CD3+CD8+cytotoxic T lymphocytes. Interestingly, within cord blood cells, BY55+lymphocytes represented 20-35% of the lymphocytes corresponding exclusively to a CD3-cell subset. Furthermore, we detected in cord blood no cytotoxic T lymphocyte activity but we demonstrated that the CD3-BY55+cell subset contained the whole natural killer activity.
We have obtained a monoclonal antibody termed BY55 that defines an 80-kDa cell-surface structure on a subset of circulating peripheral blood mononucleocytes. This structure, which was not detected on ...most cell lines or activated lymphocytes, was expressed exclusively on 15-25% of CD2+circulating lymphocytes, including a major subset within the CD3-and the T-cell receptor γδ+lymphocytes and a small percentage of the CD3+CD8+cells. Moreover, we have shown that the BY55 molecule delineated the competent killer circulating lymphocytes. In the present report, additional two- and three-color immunofluorescence studies of peripheral blood lymphocytes were done to precisely determine BY55 expression within the T-cell population. In normal individuals, peripheral blood CD3+CD8+BY55+cells represented only 5-6% of the lymphocytes, and these cells possessed cytolytic activity. Interestingly, we found that the percentage of total BY55+lymphocytes as well as the percentage of CD3+CD8+BY55+was significantly increased in peripheral blood lymphocytes of human immunodeficiency virus-seropositive individuals.
Supernumerary marker chromosomes (sSMC) may or may not be associated with an abnormal phenotype, depending on the presence of euchromatin, on their chromosomal origin and whether they are inherited. ...Over 80% of sSMCs are derived from acrocentric chromosomes and half of them include the short arm of chromosome 15. Generally, they appear as bisatellited isodicentric marker chromosomes, most of them are symmetric. These chromosomes are normally originated de novo and are associated with mild to severe intellectual disability but not with physical abnormalities. We report on a patient with an SMC studied using classical and molecular cytogenetic procedures (G and C banding, NOR staining, painting and centromeric fluorescent in situ hybridization (FISH), BAC-FISH, and SKY). The MLPA technique and DNA polymorphic markers were used in order to identify its parental origin. The marker chromosome, monosatellited and monocentric, was found to be derived from a maternal chromosome 15 and was defined as 15pter-q21.2. This is the report of the largest de novo monosatellited 15q marker chromosome ever published presenting detailed cytogenetic and clinical data. It was associated with a phenotype including cardiac defect, absence of septum pellucidum, and dysplasia of the corpus callosum.
The glycoprotein (Gp) IIb/IIIa integrin, also called CD41, is the platelet receptor for fibrinogen and several other extracellular matrix molecules. Recent evidence suggests that its expression is ...much wider in the hematopoietic system than was previously thought. To investigate the precise expression of the CD41 antigen during megakaryocyte (MK) differentiation, CD34+ cells from cord blood and mobilized blood cells from adults were grown for 6 days in the presence of stem cell factor and thrombopoietin. Two different pathways of differentiation were observed: one in the adult and one in the neonate cells. In the neonate samples, early MK differentiation proceeded from CD34+CD41− through a CD34−CD41+CD42− stage of differentiation to more mature cells. In contrast, in the adult samples, CD41 and CD42 were co-expressed on a CD34+ cell. The rare CD34+CD41+CD42− cell subset in neonates was not committed to MK differentiation but contained cells with all myeloid and lymphoid potentialities along with long-term culture initiating cells (LTC-ICs) and nonobese diabetic/severe combined immune-deficient repopulating cells. In the adult samples, the CD34+CD41+CD42−subset was enriched in MK progenitors, but also contained erythroid progenitors, rare myeloid progenitors, and some LTC-ICs. All together, these results demonstrate that the CD41 antigen is expressed at a low level on primitive hematopoietic cells with a myeloid and lymphoid potential and that its expression is ontogenically regulated, leading to marked differences in the surface antigenic properties of differentiating megakaryocytic cells from neonates and adults.
Stem cell proliferation induced by potent cytokines usually leads to a loss of primitive potential through differentiation. In this study, the ability of cytokines and murine MS5 stromal cells to ...independently regulate the proliferation and long-term culture-initiating cell (LTC-IC) activity of primitive CD34(+)CD38(low/neg) human bone marrow cells was evaluated. To compare populations with identical proliferation histories, cells were labeled with carboxy fluorescein diacetate succinimidyl ester, and LTC-IC activity was assessed 4 days later in cells that had accomplished the same number of divisions with or without MS5 cells. MS5 cells counteracted dramatically the loss of LTC-IC activity observed in the presence of cytokines alone. Thus, in the presence of MS5 cells, means of 1233 (n = 5) and 355 (n = 9) LTC-IC-derived colony-forming cells (CFCs) were generated by 1000 cells that performed 3 and 4 divisions respectively, whereas 311 (n = 5) and 64 (n = 5) CFCs were generated by 1000 cells cultured without MS5 cells. Interestingly, MS5 cells had no detectable effect on the LTC-IC activity of cells that divided only twice in 4 days-1606 CFCs (n = 6) and 1993 (n = 6) CFCs, respectively, without and with MS5 cells-and a 48 additional hours of coculture were necessary to unmask changes in the LTC-IC activity mediated by stromal cells. These results indicate that cytokines and stroma-derived signals can regulate independently the proliferation and differentiation of primitive cells and that these stroma-derived extracellular factors act directly on their target cells.
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