Navegando por Autor "Toledo, Vicente de Paulo Coelho Peixoto de"
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Item Comparative evaluation of phenol and thimerosal as preservatives for a candidate vaccine against American cutaneous leishmaniasis.(2010) Mayrink, Wilson; Tavares, Carlos Alberto Pereira; Deus, Rosângela Barbosa de; Pinheiro, Melina Barros; Guimarães, Tânia Mara Pinto Dabés; Andrade, Hélida Monteiro de; Costa, Carlos Alberto da; Toledo, Vicente de Paulo Coelho Peixoto deFor decades thimerosal has been used as a preservative in the candidate vaccine for cutaneous leishmaniasis, which was developed by Mayrink et al. The use of thimerosal in humans has been banned due to its mercury content. This study addresses the standardization of phenol as a new candidate vaccine preservative. We have found that the proteolytic activity was abolished when the test was conducted using the candidate vaccine added to merthiolate (MtVac) as well as to phenol (PhVac). The Montenegro’s skin test conversion rates induced by MtVac and by PhVac was 68.06% and 85.9%, respectively, and these values were statistically significant (p < 0.05). The proliferative response of peripheral mononuclear blood cells shows that the stimulation index of mice immunized with both candidate vaccines was higher than the one in control animals (p < 0.05). The ability of the candidate vaccines to induce protection in C57BL/10 mice against a challenge with infective Leishmania amazonensis promastigotes was tested and the mice immunized with PhVac developed smaller lesions than the mice immunized with MtVac. Electrophoresis of phenol-preserved antigen revealed a number of proteins, which were better preserved in PhVac. These results do in fact encourage the use of phenol for preserving the immunogenic and biochemical properties of the candidate vaccine for cutaneous leishmaniasis.Item Immuno-biochemical evaluations of phenol and thimerosal as antigen preservatives in Montenegro skin test.(2006) Mayrink, Wilson; Coelho, George Luiz Lins Machado; Guimarães, Tânia Mara Pinto Dabés; Andrade, Hélida Monteiro de; Peres, Elúzia de Castro; Costa, Carlos Alberto da; Toledo, Vicente de Paulo Coelho Peixoto deMontenegro skin test (MST) represents the main complementary diagnostic test for tegumentary leishmaniases (TL) in endemic regions. Most antigen formulations used for the MST contain thimerosal as preservative. The Food and Drug Administration (FDA), however, recommended reducing or eliminating thimerosal from vaccines and other biological reagents and the Agˆencia Nacional de Vigilˆancia Sanit´aria (ANVISA) in Brazil, prohibited the use of mercurial compounds in immunobiologicals. In the search for an alternative stabilizer, phenol and thimerosal were tested as antigen preservatives in MST. Formulations were tested when fresh and after a 12-month storage at 4 ◦C in TL confirmed mice and human patients, and were evaluated for protein constitution by SDS-PAGE, Western blot and anti-gp63 ELISA. In mice, a decrease in the diagnostic effectiveness in merthiolate formulation was observed after a 12-month storage. SDS-PAGE, Western blot and anti-gp63 ELISA analyses showed a degradation of antigen proteins in both formulations after 12-month storage and that phenol-preserved antigen was quantitatively and qualitatively better than the merthiolate-preserved one. In patients, the average of induration diameter was larger in fresh antigens (p < 0.05). However, storage time did not jeopardize their diagnostic capacity.No non-specific reactions produced by phenol or merthiolate were observed neither in humans nor in mice. Phenol could be a good alternative to replace the merthiolate in MST, and despite the proteolytic activity, antigens remain viable for at least 12 months.Item Immunochemotherapy in american cutaneous leishmaniasis : immunological aspects before and after treatment.(2001) Toledo, Vicente de Paulo Coelho Peixoto de; Mayrink, Wilson; Gollob, Kenneth John; Oliveira, Milton Adriano Pelli de; Costa, Carlos Alberto da; Genaro, Odair; Pinto, J. A.; Afonso, Luís Carlos CroccoIn this study, we evaluated the immune response of patients suffering from cutaneous leishmaniasis treated with two distinct protocols. One group was treated with conventional chemotherapy using pentavalent antimonium salts and the other with immunochemotherapy where a vaccine against cutaneous leishmaniasis was combined with the antimonium salt. Our results show that, although no differences were observed in the necessary time for complete healing of the lesions between the two treatments, peripheral blood mononuclear cells from patients treated by chemotherapy showed smaller lymphoproliferative responses at the end of the treatment than those from patients in the immunochemotherapy group. Furthermore, IFN-production was also different between the two groups. While cells from patients in the chemotherapy group produced more IFN-at the end of treatment, a significant decrease in this cytokine production was associated with healing in the immunochemotherapy group. In addition, IL-10 production was also less intense in this latter group. Finally, an increase in CD8+ -IFN-producing cells was detected in the chemotherapy group. Together these results point to an alternative treatment protocol where healing can be induced with a decreased production of a potentially toxic cytokine.Item Vaccination of C57BL/10 mice against cutaneous leishmaniasis using killed promastigotes of different strains and species of Leishmania.(2002) Mayrink, Wilson; Santos, Gilmara Cristina dos; Toledo, Vicente de Paulo Coelho Peixoto de; Guimarães, Tânia Mara Pinto Dabés; Coelho, George Luiz Lins Machado; Genaro, Odair; Costa, Carlos Alberto daAntigenic extracts from five Leishmania stocks were used to vaccinate C57BL/10 mice. The Leishvacinand PH8 monovalent vaccine yielded the highest IFN-levels in the supernatants of spleen cell culture from vaccinated animals. Each single strain immunized group showed evidence of protective immunity six months after the challenge with promastigotes of Leishmania (Leishmania) amazonensis. No differences were detected between the vaccinated groups. It can be concluded that vaccines composed of single Leishmania stocks can provide protection to C57BL/10 mice against L. (L.) amazonensis infection.Item Vaccine for prophylaxis and immunotherapy, Brazil.(1996) Genaro, Odair; Toledo, Vicente de Paulo Coelho Peixoto de; Costa, Carlos Alberto da; Hermeto, Marco Victor; Afonso, Luís Carlos Crocco; Mayrink, Wilson