EXPRESSION IN ESCHERICHIA-COLI OF A DOMINANT IMMUNOGEN OF TRYPANOSOMA-CRUZI RECOGNIZED BY HUMAN CHAGASIC SERA

28351952

Optimal MHC-II-restricted tumor antigen presentation to CD4+ T helper cells: the key issue for development of anti-tumor vaccines

Present immunoprevention and immunotherapeutic approaches against cancer suffer from the limitation of being not “sterilizing” procedures, as very poor protection against the tumor is obtained. Thus newly conceived anti-tumor vaccination strategies are urgently needed. In this review we will focus on ways to provide optimal MHC class II-restricted tumor antigen presentation to CD4+ T helper cells as a crucial parameter to get optimal and protective adaptive immune response against tumor. Through the description of successful preventive or therapeutic experimental approaches to vaccinate the host against the tumor we will show that optimal activation of MHC class II-restricted tumor specific CD4+ T helper cells can be achieved in various ways. Interestingly, the success in tumor eradication and/or growth arrest generated by classical therapies such as radiotherapy and chemotherapy in some instances can be re-interpreted on the basis of an adaptive immune response induced by providing suitable access of tumor-associated antigens to MHC class II molecules. Therefore, focussing on strategies to generate better and suitable MHC class II–restricted activation of tumor specific CD4+ T helper cells may have an important impact on fighting and defeating cancer

Indução da atividade fagocitária e produção de óxido nítrico numa população natural de Trypanosoma cruzi I e II do Estado do Paraná, Brasil

Twelve strains of Trypanosoma cruzi isolated from wild reservoirs, triatomines, and chronic chagasic patients in the state of Paraná, southern Brazil, and classified as T. cruzi I and II, were used to test the correlation between genetic and biological diversity. The Phagocytic Index (PI) and nitric-oxide (NO) production in vitro were used as biological parameters. The PI of the T. cruzi I and II strains did not differ significantly, nor did the PI of the T. cruzi strains isolated from humans, triatomines, or wild reservoirs. There was a statistical difference in the inhibition of NO production between T. cruzi I and II and between parasites isolated from humans and the strains isolated from triatomines and wild reservoirs, but there was no correlation between genetics and biology when the strains were analyzed independently of the lineages or hosts from which the strains were isolated. There were significant correlations for Randomly Amplified Polymorphic Deoxyribonucleic acid (RAPD) and biological parameters for T. cruzi I and II, and for humans or wild reservoirs when the lineages or hosts were considered individually.Doze cepas de Trypanosoma cruzi isoladas de reservatórios silvestres, triatomíneos e de pacientes chagásicos crônicos do Estado do Paraná, Brasil, classificadas como Tc I e II foram usadas para avaliar a correlação entre genética e diversidade biológica. Índice fagocítico (IF) e produção de óxido nítrico (ON) in vitro foram os parâmetros biológicos utilizados. O IF de cepas T. cruzi I e II não diferiram significativamente assim como o IF de cepas isoladas de humanos, triatomíneos ou de reservatórios silvestres. Há diferença estatística na inibição da produção de ON entre T. cruzi I e II e entre parasitos isolados de humanos e de cepas isoladas de triatomíneos e reservatórios silvestres, mas não foi observada correlação entre genética e biologia quando as cepas foram analisadas independentemente da linhagem ou hospedeiros das quais elas foram isoladas. Observou-se correlação significativa para amplificação aleatória do DNA polimórfico e parâmetros biológicos de Tc I ou II e para os seres humanos ou reservatório silvestre quando linhagens ou hospedeiros são consideradas separadamente