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Luque M.C.A.,Heart Institute of Sao Paulo InCor | Luque M.C.A.,University of Sao Paulo | Gutierrez P.S.,Heart Institute of Sao Paulo InCor | Debbas V.,Heart Institute of Sao Paulo InCor | And 4 more authors.
Molecular Immunology | Year: 2015

Leukocyte migration is essential for the function of the immune system. Their recruitment from the vessels to the tissues involves sequential molecular interactions between leukocytes and endothelial cells (ECs). Many adhesion molecules involved in this process have already been described. However, additional molecules may be important in this interaction, and here we explore the potential role for CD100 and plexins in monocyte-EC binding.CD100 was shown to be involved in platelet-endothelial cell interaction, an important step in atherogenesis and thrombus formation. In a recent work we have described CD100 expression in monocytes and in macrophages and foam cells of human atherosclerotic plaques. In the present work, we have identified plexin B2 as a putative CD100 receptor in these cells. We have detected CD100 expression in the endothelium as well as in in vitro cultured endothelial cells. Blocking of CD100, plexin B1 and/or B2 in adhesion experiments have shown that both CD100 and plexins act as adhesion molecules involved in monocyte-endothelial cell binding. This effect may be mediated by CD100 expressed in both cell types, probably coupled to the receptors endothelial plexin B1 and monocytic plexin B2. These results can bring new insights about a possible biological activity of CD100 in monocyte adhesion and atherosclerosis, as well as a future candidate for targeting therapeutics. © 2015 The Authors.

Deng X.,Blood Systems Research Institute | Sabino E.C.,University of Sao Paulo | Cunha-Neto E.,University of Sao Paulo | Cunha-Neto E.,Institute for Investigation in Immunology | And 7 more authors.
PLoS ONE | Year: 2013

Background: Familial aggregation of Chagas cardiac disease in T. cruzi-infected persons suggests that human genetic variation may be an important determinant of disease progression. Objective: To perform a GWAS using a well-characterized cohort to detect single nucleotide polymorphisms (SNPs) and genes associated with cardiac outcomes. Methods: A retrospective cohort study was developed by the NHLBI REDS-II program in Brazil. Samples were collected from 499 T. cruzi seropositive blood donors who had donated between1996 and 2002, and 101 patients with clinically diagnosed Chagas cardiomyopathy. In 2008-2010, all subjects underwent a complete medical examination. After genotype calling, quality control filtering with exclusion of 20 cases, and imputation of 1,000 genomes variants; association analysis was performed for 7 cardiac and parasite related traits, adjusting for population stratification. Results: The cohort showed a wide range of African, European, and modest Native American admixture proportions, consistent with the recent history of Brazil. No SNPs were found to be highly (P<10-8) associated with cardiomyopathy. The two mostly highly associated SNPs for cardiomyopathy (rs4149018 and rs12582717; P-values <10-6) are located on Chromosome 12p12.2 in the SLCO1B1 gene, a solute carrier family member. We identified 44 additional genic SNPs associated with six traits at P-value <10-6: Ejection Fraction, PR, QRS, QT intervals, antibody levels by EIA, and parasitemia by PCR. Conclusion: This GWAS identified suggestive SNPs that may impact the risk of progression to cardiomyopathy. Although this Chagas cohort is the largest examined by GWAS to date, (580 subjects), moderate sample size may explain in part the limited number of significant SNP variants. Enlarging the current sample through expanded cohorts and meta-analyses, and targeted studies of candidate genes, will be required to confirm and extend the results reported here. Future studies should also include exposed seronegative controls to investigate genetic associations with susceptibility or resitance to T. cruzi infection and non-Chagas cardiomathy. © 2013 Deng et al.

Silveira C.,Federal University of Sao Paulo | Vallochi A.L.,University of Sao Paulo | Da Silva U.R.,University of Sao Paulo | Muccioli C.,Federal University of Sao Paulo | And 6 more authors.
British Journal of Ophthalmology | Year: 2011

Background and aims: Toxoplasmic retinochoroiditis may recur months or years after the primary infection. Rupture of dormant cysts in the retina is the accepted hypothesis to explain recurrence. Here, the authors present evidence supporting the presence of Toxoplasma gondii in the peripheral blood of immunocompetent patients. Methods: Direct observation by light microscopy and by immunofluorescence assay was performed, and results were confirmed by PCR amplification of parasite DNA. Results: The authors studied 20 patients from Erechim, Brazil, including acute infected patients, patients with recurrent active toxoplasmic retinochoroiditis, patients with old toxoplasmic retinal scars, and patients with circulating IgG antibodies against T gondii and absence of ocular lesions. Blood samples were analysed, and T gondii was found in the blood of acutely and chronically infected patients regardless of toxoplasmic retinochoroiditis. Conclusions: The results indicate that the parasite may circulate in the blood of immunocompetent individuals and that parasitaemia could be associated with the reactivation of the ocular disease.

Coelho V.,University of Sao Paulo | Coelho V.,Institute for Investigation in Immunology | Saitovitch D.,Institute for Investigation in Immunology | Saitovitch D.,Grande Rio University | And 4 more authors.
Current Opinion in Organ Transplantation | Year: 2013

PURPOSE OF REVIEW: To discuss the B-cell diverse functions in organ transplantation, highlighting the emerging debate on the role of regulatory B cells (Bregs). We underscore the need to re-examine and integrate data on B-cell functional activities, aiming to discriminate their regulatory (REG) and inflammatory (INFLAMMA) functions and to translate this knowledge for the development of novel immunomodulatory therapeutic strategies and to rethink the current ones. RECENT FINDINGS: Data from both experimental models and clinical trials point that B cells of various phenotypes have immunoregulatory activity and play an important role in controlling graft inflammation. Data on the state of operational tolerance, in kidney transplantation, suggest the relevance of preserving a healthy B-cell compartment-in numbers and in the Breg capacity to activate the CD40/STAT3 signalling pathway-for achieving and maintaining homeostasis. Moreover, autoantibodies also comprise transplant immunobiology and it seems that not all alloantibodies are deleterious. SUMMARY: The role of B cells, in organ transplantation, can no longer be taken as mere generators of plasma cells, which produce alloantibodies deleterious to the graft. B cells also seem to integrate a complex immunoregulatory network in organ transplantation, with Bregs of various phenotypes and possibly also antibodies. The functional discrimination of REG/INFLAMMA B-cell roles needs to be considered in the clinical setting. © 2013 Wolters Kluwer Health | Lippincott Williams &Wilkins.

Porto G.,University of Sao Paulo | Giordano R.J.,University of Houston | Giordano R.J.,University of Sao Paulo | Marti L.C.,Instituto Israelita Of Ensino E Pesquisa Albert Einstein | And 7 more authors.
PLoS ONE | Year: 2011

Thymic CD4+CD25+ cells play an important role in immune regulation and are continuously developed in the thymus as an independent lineage. How these cells are generated, what are their multiple pathways of suppressive activity and which are their specific markers are questions that remain unanswered. To identify molecules involved in the function and development of human CD4+CD25+ T regulatory cells we targeted thymic CD4+CD25+ cells by peptide phage display. A phage library containing random peptides was screened ex vivo for binding to human thymic CD4+CD25+ T cells. After four rounds of selection on CD4+CD25+ enriched populations of thymocytes, we sequenced several phage displayed peptides and selected one with identity to the Vitamin D Receptor (VDR). We confirmed the binding of the VDR phage to active Vitamin D in vitro, as well as the higher expression of VDR in CD4+CD25+ cells. We suggest that differential expression of VDR on natural Tregs may be related to the relevance of Vitamin D in function and ontogeny of these cells. © 2011 Porto et al.

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