Clinical and immunological aspects of envenomations by Bothrops snakes: [review]

Accidents caused by snakes, especially in tropical and subtropical countries, still constitute a serious public health problem due to the lack of knowledge of health professionals and the precariousness of health systems in the regions where most accidents occur. Snake venoms contain a range of molecules that may provoke local swelling, pain, renal and respiratory insufficiencies. The study of the effects of each molecule on humans can help the development of complementary therapy. Similarly, the knowledge of clinical aspects of envenomations provides a better identification and implementation of appropriate treatment. In addition, to understand Bothrops envenomations and improve the therapeutic strategy, it is necessary to understand and study the role of important inflammatory mediators, particularly nitric oxide (NO), cytokines and the complement system.

Immunophenotypic characterization of patients with American cutaneous leishmaniasis prior to and after treatment in Pernambuco, Brazil

Leishmania infections induce a specific activation of host immunological response, particularly characterized by T cell expansion. Studies indicate the importance of the balance between CD4+ and CD8+ T cells, in which the first ones would have their number reduced during the healing process. Meanwhile, CD25+ T cells have been associated with the suppression of the immune response. Since the immune response has an essential role in both healing and progression of diseases, this study aimed to identify the percentage of CD3+, CD4+, CD8+, CD16+ and CD25+ T cells in the peripheral blood of patients afflicted with American cutaneous leishmaniasis (ACL) - before and after treatment - and healthy controls. Peripheral blood was collected and transferred to cytometry tubes containing monoclonal antibodies specific for cell surface markers CD3, CD4, CD8, CD16 e CD25. The immunophenotypic and morphometric parameters of cells were determined by flow cytometry and the results demonstrated a significant increase in the number of T CD8+ cells after treatment, suggesting a cytotoxic T cell response. An increase in CD25+ T cells in patients with active ACL and after treatment was also observed, suggesting the participation of these cells in the modulation of the exacerbated effector response.

Immunological studies and in vitro schistosomicide action of new imidazolidine derivatives

Schistosomiasis is a major public health problem with 207 million people infected and more than 779 million at risk. The drug of choice for treating schistosomiasis is praziquantel (PZQ); however, it is inefficient against immature forms of schistosomes. The aim of this study was to test new imidazolidine derivatives LPSF/PT09 and LPSF/PT10 against adult Schistosoma mansoni worms. IC50, cytotoxicity, immune response and cell viability assays were also available for these imidazolidines. Different concentrations of imidazolidine, from 32 to 320 »M, promoted motor abnormalities in breeding and unpaired worms, and death in 24 hours at higher concentrations. Although LPSF/PT09 and LPSF/PT10 did not affect IFN-³ and IL-10 production, they induced nitric oxide production and showed a similar behavior to praziquantel on cell death test. Thus, these new imidazolidine derivatives should undergo further study to develop schistosomiasis drugs.

Protective immunity of single and multi-antigen DNA vaccines against schistosomiasis

We evaluated the usefulness of the combination of three plasmids encoding tegumental (pECL and pSM14) and muscular (pIRV5) antigens of the Schistosoma mansoni on improving the protective immunity over the use of a single antigen as DNA vaccines. Female BALB/c mice were inoculated twice with 25 æg DNA plasmid within two weeks interval. The challenge was performed with 80 cercarias of a regional isolate of S. mansoni (SLM) one week after the last immunization. Six weeks after challenge, all mice were perfused for worm load determination. The following groups were analyzed: saline; empty vector; monovalent formulations of pECL; pSM14 and pIRV5 and also double combinations of pECL/pIRV5 and pIRV5/pSM14 and a triple combination of pECL/pIRV5/pSM14. The protection was expressed as a percentage of worm loads in each group compared with the saline group. The results obtained were 41 percent (p < 0.05); 52 percent (p < 0.05); 51 percent (p < 0.05); 48 percent (p < 0.05); 55 percent (p < 0.05); 45 percent (p < 0.05); 65 percent (p < 0.05) for each group respectively