Time filter

Source Type

Sainte-Foy-lès-Lyon, France

Infynity Biomarkers, French National Center for Scientific Research, University of Lyon and Hospices Civils De Lyon | Date: 2010-05-06

Antibodies which specifically bind to a peptide having the sequence Ala-Ala-Ala-Pro-Ala-Lys-Ala-Ala-Ala-Ala-Pro-Ala-Lys-Thr-Ala-Ala-Ala-Pro-Val (SEQ ID N

Saba E.S.,INFYNITY Biomarkers | Saba E.S.,Laboratories of Bacteriology Virology | Gueyffier L.,INFYNITY Biomarkers | Danjoy M.-L.,INFYNITY Biomarkers | And 6 more authors.

Antibodies named TcCRA "Trypanosoma cruzi Cross Reactive Antibodies" were detected in 47% of blood donors from French population unexposed to the parasite. In order to evaluate the passive or active transmissibility of TcCRA and further characterize its role and etiology, we have conducted a study in a cohort of 47 patients who underwent allogeneic Hematopoietic Stem Cell Transplantations (allo-HSCT). Donors and recipients were tested for TcCRA prior to transplantation. Recipients were further tested during follow-up after transplantation. Demographical, clinical and biological data were collected. Our primary end-point was to assess the risk of TcCRA acquisition after transplantation. During this initial analysis, we observed no seroconversion in patients receiving cells from TcCRA negative donors (n = 23) but detected seroconversion in 4 out of 24 patients who received hematopoietic stem cells from positive donors. Here, we are discussing possible scenarios to explain TcCRA-immune status in recipient after transplantation. Copyright: © 2015 Saba et al. Source

Saba E.S.,INFYNITY Biomarkers | Saba E.S.,Laboratory of Bacteriology Virology | Gueyffier L.,INFYNITY Biomarkers | Dichtel-Danjoy M.-L.,INFYNITY Biomarkers | And 8 more authors.

Cross-reactive antibodies are characterized by their recognition of antigens that are different from the trigger immunogen. This happens when the similarity between two different antigenic determinants becomes adequate enough to enable a specific binding with such cross-reactive antibodies. In the present manuscript, we report the presence, at an "abnormal" high frequency, of antibodies in blood samples from French human subjects cross-reacting with a synthetic-peptide antigen derived from a Trypanosoma cruzi (T. cruzi) protein sequence. As the vector of T. cruzi is virtually confined to South America, the parasite is unlikely to be the trigger immunogen of the cross-reactive antibodies detected in France. At present, the cross-reactive antibodies are measured by using an in-house ELISA method that employs the T. cruzi -peptide antigen. However, to underline their cross-reactive characteristics, we called these antibodies "Trypanosoma cruzi Cross Reactive Antibodies" or TcCRA. To validate their cross-reactive nature, these antibodies were affinity-purified from plasma of healthy blood donor and were then shown to specifically react with the T. cruzi parasite by immunofluorescence. Seroprevalence of TcCRA was estimated at 45% in serum samples of French blood donors while the same peptide-antigen reacts with about 96% of T. cruzi -infected Brazilian individuals. In addition, we compared the serology of TcCRA to other serologies such as HSV 1/2, EBV, HHV-6, CMV, VZV, adenovirus, parvovirus B19, mumps virus, rubella virus, respiratory syncytial virus, measles and enterovirus. No association was identified to any of the tested viruses. Furthermore, we tested sera from different age groups for TcCRA and found a progressive acquisition starting from early childhood. Our findings show a large seroprevalence of cross-reactive antibodies to a well-defined T. cruzi antigen and suggest they are induced by a widely spread immunogen, acquired from childhood. The etiology of TcCRA and their clinical relevance still need to be investigated. © 2013 Saba et al. Source

Granjon E.,INFYNITY Biomarkers | Dichtel-Danjoy M.-L.,INFYNITY Biomarkers | Saba E.,INFYNITY Biomarkers | Sabino E.,University of Sao Paulo | And 2 more authors.
PLoS Neglected Tropical Diseases

Background: Chagas disease is due to the parasite Trypanosoma cruzi, a protist disseminated by a Triatome vector. This disease is endemic to Latin America and considered by WHO as one of the 17 world’s neglected diseases. In Europe and in North America, imported cases are also detected, due to migration of population outside of the endemic region. Diagnosis of T. cruzi infection is usually made indirectly by the detection of specific antibodies to T. cruzi antigens. Following initial diagnostic evaluation or screening test (qualifying or discarding blood donation), a confirmation test is performed for samples initially reactive. The test presented in this study aims at the confirmation/refutation of the infectious status of human blood samples and will permit taking appropriate clinical measures. Methodology/Principal Findings: We designed a novel array of twelve antigens and printed these antigens onto 96-well plates. We tested 248 positive samples T. cruzi, 94 unscreened blood donors’ samples from non-endemic area, 49 seronegative blood donors, 7 false-positive and 3 doubtful samples. The observed reactivities were analyzed to propose a decision-tree algorithm that correctly classifies all the samples, with the potential to discriminate false-positive results and sticky samples. We observed that antibodies levels (Sum of all antigens) was significantly higher for PCR positive than for PCR negative samples in all studied groups with Multi-cruzi. Conclusion/Significance: The results described in this study indicate that the Multi-cruzi improves the serological confirmation of Chagas disease. Moreover the “sum of all antigens” detected by Multi-cruzi could reflect parasitemia level in patients–like PCR signals does—and could serve as an indicator of parasite clearance in longitudinal follow-ups. Validation of this assay is still required on an independent large collection of well characterized samples including typical false-reactive samples such as Leishmaniasis. © 2016 Granjon et al. Source

Discover hidden collaborations