Cinética de migração celular e expressão da enzima óxido nítrico sintase induzida (iNOS) na pele de cães imunizados com componentes antigênicos de uma nova vacina contra Leishmaniose Visceral Canina (LVC)
The search for new immunobiologicals against Canine Visceral Leishmaniasis (CVL), able to activate a long-term and protective immune response in dogs, has intensified in the last decade. However, it still remains to be elucidated that mechanisms of the innate immune response in situ after immunization (a.i.). The main objective of the present study was to assess the kinetics of cell migration in the skin dogs with distinct antigenic components of the LBSap-vaccine. In the current study, 15 mixed breed dogs of both genders aging from 8-12-month old were inoculated in the dorsal region by intradermic injections and subdivided within five experimental groups: (i) saline control group (SC) received 250 µL of sterile 0.9% saline; (ii) saponin group (Sap), received 1 mg of saponin; (iii) Saliva group (Sal), received 1 acini of salivary glands of Lutzomyia longipalpis; (iv) Leishmania braziliensis antigen group (LB) received 600 µg/protein of L. braziliensis; and (v) L. braziliensis vaccine plus saponin group (LBSap) received 600 µg/protein of L. braziliensis plus 1 mg of saponin. After the times of 1, 12, 24, 48 and 96 hours, skin biopsies were performed. The results indicated that saponin adjuvant alone or combined with L. braziliensis antigen induced strong local acute inflammatory reaction accompanied by edema, hemorrhage and congestion. However, these reactions not progressed to ulcerated lesions. The image analysis by morformetry showed the intensity of cell infiltrate and an increased number of cell-nuclei in dermis of the Sap group. In hypodermis, this increase was more intense than in the dermis, observed in LBSap and Sap groups. Overall, the cell profile found in Sap and LBSap was composed of neutrophils, lymphocytes and eosinophils suggesting a profile of mixed immune response (type1/type2) potentially compatible with effective control of the etiological agent of CVL. These analyses highlight the role of saponin as a potent stimulator of cell-immune response and important on antigenic priming events and development of protective immune response after immunization. In group Sal, it was observed increase of eosinophils in the hypodermis demonstrating the role of saliva as immunomodulator at the beginning of Leishmania infection. There was also increased production of iNOS in Sap and LBSap groups. These data, allowing us to infer that this increase could be important for the microenvironment composed of cytokines and chemokines with of type-1 profile. Thus, we can conclude that immunization by LBSap and the saponin adjuvant elicited a potential innate-immune activations status compatible with effective control of the resistance to infection by Leishmania and contributing to a better understanding of the innate-immunity events induced by the LBSap vaccine.
Advisor:Marta de Lana; Alexandre Barbosa Reis; Claúdia Martins Carneiro; Maria Norma Mello
School:Universidade Federal de Ouro Prêto
Source Type:Master's Thesis
Keywords:cinética de migração celular enzima óxido nítrico leishmaniose visceral canina lvc pele cães imunizados imunologia
Date of Publication:01/29/2008