Interferons: in the out of the net

Cytokines are soluble polypeptides whose primary function is signalling from cell to cell. Within the immune system, cytokines function in a complex network, and are responsible for proper development and differentiation of cells and organs, as well as for controlling the humoral and cellular responses. Interferons (IFNs), best known for their antiviral activity, are cytokines that can modulate various functions of the immune system. In this review some aspects of the interactions between IFNs and other cytokines will be presented. In considering IFNs in the net, we will discuss their interations with other cytokines as well as the role of the transcription factor IRF-1 as a candidate for linking the cytokine network. To understand the immune system having IFNs out of the net, we have generated some "knock-out"mice deleted for specific components of the interferon system. These animals proved to be an important tool to clarify the role of these cytokines in the mechanism of defense and development of the immune system.

Human immune responses during schistosomiasis mansoni

O estudo da resposta imune de pacientes com esquistossomose progride em funçäo do avanço tecnológico, apesar das dificuldades de manipulaçäo in vivo deste complexo sistema parasita-hospedeiro. A ênfase nos estudos tem sido mais freqüentemente dirigida para comparaçöes entre grupos característicos de indivíduos, tais como infectado/näo infectado, reinfectado/näo reinfectado, assintomático/hepato-esplênico, com intensidade de infecçäo alta/baixa, etc. Baseado nessas comparaçöes razoáveis com relaçäo à regulaçäo imunológica, susceptibilidade e resistência e até mesmo consideraçöes sôbre mecanismos, que têm sido mais apropriadamente analisados, entretanto, em sistemas experimentais. Tais estudos têm como finalidade a compreensäo das causas e eventos que levam à morbidade e ao desenvolvimento de uma vacina humana anti-esquistosoma

Immunopathology of American cutaneous leishmaniasis

American mucocutaneous leishmaniasis is a granulomatous disease clinically characterized by ulcerated skin lesions that can regress spontaneously. A small percentage of the affected individuals can however develop a severe destruction of the nasal, oral, pharyngeal and/or laryngeal mucous membranes many years after the healing of the primary lesion. The human immune response to the infection and the possible mechanisms underlying the pathogenesis of the disease, determining either the self-healing or the development of chronic and destructive mucosal lesions, are discussed