AVALIAÇÃO DA RESPOSTA IMUNE HUMORAL EM ANIMAIS IMUNIZADOS COM ANTÍGENOS TOTAIS DE Leishmania amazonensis ASSOCIADOS A DIFERENTES ADJUVANTES VACINAIS
Leishmania amazonenses. Adjuvants. VPs. Leishmania amazonensis antigens. Immunization.
Neglected tropical diseases (NTDs) are a major public health challenge. Leishmaniasis, a classic example of these NTDs, affects millions of people around the world, especially those in poverty and vulnerability. Its treatment consists on the use of pentavalent antimonials or amphotericin B, which are toxic and expensive. Currently, the means for prevention of Leishmaniasis is through vector control and treatment of the disease reservoir, in this case, dogs. However, such measures are inefficient, making it necessary to develop a more safe and effective alternative. In this scenario, vaccines presente themselves an alternative, not only for prophylaxis, but also for treatment. Therefore, the present study aimed to characterize the immunostimulatory capacity of total Leishmania amazonensis antigens, parallel to the evaluation of the Triatoma-virus’s structural proteins (VP1, VP2, and VP3) immunoadjuvant potential comparing their activity to adjuvants estabilished in the literature, such as: Freud’s adjuvante and aluminum hydroxide. Initially, promastigotes of L. amazonensis were cultivated; a total protein extract was obtained and the electrophoretic profile was characterized. After these processes, BALB/c mice (Mus musculus) were divided into five groups: PBS (negative control), L. amazonensis extract (G2) and groups with adjuvants, named: Freund's adjuvant (G3), aluminum (G4), VPs (G5). The groups were submitted to primary (100μg) and secondary (100μg) immunizations, with an interval of 30 days between them. Serum samples were obtained 15 and 30 days from the primary immunization, and 7, 15, 30, 40, 50 and 60 days after the booster. To this date, the total IgG specific antibodies profile has been characterized from all collection points. The IgG1, IgG2a, IgG2b and IgG3 subtypes were determined only on the last collection point, 90 days after the beginning of the experiment. The DTH reaction (Delayed Hypersensitivity Reaction) and a spleen cells culture from immunized animals were performed to characterize the cellular imune response, so that in the future, a quantification of cytokines through immunoassay can be carried out. Beforehand, the results obtained show the immunostimulatory character of the adjuvants used, as well as the ability of VPs to preferentially induce IgG2b and IgG3 antibodies. As the ELISA of the isotypes was only performed from the last collection point (D90), it will be necessary to perform other points to conclude which response profile was modulated in the face of the immunization process established by this study.