Design, Construction, and Evaluation of a Specific Chimeric Antigen To Diagnose Chagasic Infection

Chagas' disease is routinely diagnosed by detecting specific antibodies (Abs) using serological methods. The methodology has the drawback of potential cross-reactions with Abs raised during other infectious and autoimmune diseases (AID). Fusion of DNA sequences encoding antigenic proteins is a versatile tool to engineer proteins to be used as sensitizing elements in serological tests. A synthetic gene encoding a chimeric protein containing the C-terminal region of C29 and the N-terminal region of TcP2β was constructed. A 236-serum panel, composed of 104 reactive and 132 nonreactive sera to Chagas' disease, was used to evaluate the performance of the chimera. Among the nonreactive sera, 65 were from patients with AID (systemic lupus erythematosus and rheumatoid arthritis) or patients infected with Leishmania brasiliensis, Brucella abortus, Streptococcus pyogenes, or Toxoplasma gondii. The diagnostic performances of the complete TcP2β (TcP2β(FL)) and its N-terminal region (TcP2β(N)) were evaluated. TcP2β(FL) showed unspecific recognition toward leishmaniasis (40%) and AID Abs (58%), while TcP2β(N) showed no unspecific recognition. The diagnostic utility of the chimera was evaluated by analyzing reactivity and comparing the results with those obtained with TcP2β(N). The chimera reactivity was higher than that of the peptide fractions (0.874 versus 0.564 optical density, P = 0.0017). The detectability and specificity were both 100% for the whole serum panel tested. We conclude that the obtained chimera shows an improved selectivity and sensitivity compared with other ones previously reported, therefore displaying an optimized performance for Trypanosoma cruzi infection diagnosis

QSAR studies of indoyl aryl sulfides and sulfones as reverse transcriptase inhibitors

The inhibitory HIV reverse transcriptase activity of 172 non-nucleoside indoyl aryl sulfones and sulfides is studied with a QSAR analysis, in order to identify the molecular characteristics influencing the interaction with the reverse transcriptase enzyme. This work increases the available QSAR studies of indoyl aryl sulfones and sulfides using the reported experimental EC50 values against HIV-1 wild type (IIIB) in human T-lymphocyte (CEM) cells. Different approaches are proposed, involving 0D, 1D and 2D molecular descriptors from PaDEL freeware, and also based on flexible descriptors from CORAL freeware. Three models are finally presented, which correlate the inhibitory HIV reverse transcriptase activity with good accuracy. It is demonstrated that the established models are predictive in the validation process. The novelty of the present work relies on the development of structure-inhibitory HIV activity relationships, through a computational technique that does not require the knowledge of the molecular conformation during the structural representation. The obtained results would contribute to guide the design of more effective compounds for HIV treatment.Fil: Duchowicz, Pablo Román. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Bacelo, Daniel Enrique. Universidad de Belgrano. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fioressi, Silvina Ethel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Belgrano. Facultad de Ciencias Exactas y Naturales. Departamento de Química; ArgentinaFil: Palermo, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Ibezim, Nnenna E.. University of Nigeria; NigeriaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Exactas. Cátedra de Química Orgánica; Argentin