Avaliação de imunogenicidade de camundongos BALB/c após inoculação com proteína ligante de heparina de Leishmania chagasi

• Autor(a) principal: Carvalho, Thaís Vieira de
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2377
• topic: Leishmaniose visceral; Heparina; Lectinas; Imunologia; Rato com animal de laboratório; Visceral leishmaniasis; Heparin; Lectins; Immunology; Mouse with laboratory animals; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Visceral leishmaniasis (VL) is a disease caused by the intracellular protozoan Leishmania infantum/chagasi. This protozoa exhibit a strong tendency to invade the viscera causing severe lesions, which may result in patient death if not treated. Molecules in the parasite, considered as virulence factors, have been intensively searched. Among them are heparin-binding proteins (HBP), glycoproteins that are related in many works of the literature with the process of adhesion between cells. In this work, we used L. chagasi HBP (HBPLc) in immunization experiments using BALB/c mice to evaluate immunogenicity of the protein. Thus, we evaluate the cell proliferation and cytokines (IFN-γ, IL-4 and IL-10), NO and antibody isotypes IgG1 and IgG2a production following immunization with L. chagasi HBP (HBPLc), associated or not with Incomplete Freund s Adjuvant (IFA). The mice were intraperitoneally immunized and submitted two times to booster doses using the same protocol of the first immunization. Before each immunization, blood was collected to obtain serum for the dosage of the antibody isotypes IgG1 and IgG2a. Two weeks after the second booster, the animals were euthanized and the spleen was collected for lymphoproliferation assay, analysis of cytokines and NO production by ELISA and Griess method, respectively. Our results showed that spleen cells from HBPLc vaccinated group after in vitro stimulus with crude extract of L. chagasi (AgLc) or with HBPLc showed an increase in cell proliferation and IFN-γ, IgG2a, NO and IL-10 production if compared with spleen cells from non-vaccinated group, but with higher levels of IFN-γ and lower levels of IgG1 if compared with spleen cells from HBPLc + IFA vaccinated group submitted to the same stimulus. Otherwise, HBPLc + IFA vaccinated group, under the same in vitro stimuli conditions above, showed higher levels of lymphoproliferation and IFN-γ, NO, IL-4, IgG2a, IgG1 and IL-10 in the spleen if compared with the results obtained from non-vaccinated group. As can be seen, two distinct profiles of immune response after immunizations were obtained, being a Th1 profile observed in the group immunized only with HBPLc and Th1/Th2 mixed profile when the protein was associated with IFA. These results show that HBPLc is a candidate antigen for use in vaccine formulations and additional experiments to evaluating the performance of protection against L. chagasi challenge should be conducted to evaluate the use of HBPLc in the control of LV.