Chapter category: Infectious Disease
Impact of Polyclonal Lymphocyte Responses on Parasite Evasion and Persistence
Molecular Mechanisms of Pathogenesis in Chagas Disease
Edited by: JohnM. KellyISBN: 0-306-47849-8
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Chapter authors:
Paola Minoprio
In the field of immunoparasitology it is generally accepted that the survival and degree of pathogenicity of parasites is inextricably linked to their ability to escape and resist immune responses. Thus, numerous strategies have been proposed to explain the ability of micro-organisms to avoid immune surveillance and to persist within the host. However, the complex interactions between an infectious agent and its host that take place after infection and ultimately determine the state of susceptibility, or resistance to the development of pathology do not only rely on the "creativity" of micro-organisms. The genetic background of the host, the diversity, dynamics and activities of the immune system, and the events that precede 'immune reactions', are fundamental in determining the future of an infectious process.
In this Chapter I shall briefly review our own work in this area and present evidence for a relationship between the magnitude of polyclonal lymphocyte activation triggered by Trypanosoma cruzi parasites and the decreased resistance of the host to infection and to the development of tissue pathology. It is also apparent that polyclonally activated immune systems respond weakly to antigenic challenges as long as the state of activation is maintained. This may seem paradoxical. However this state of refractoriness/anergy is invariably and intimately associated with high levels of lymphocyte activation. This seems to be a consequence of the fact that very few of the multitude of lymphocyte clones that are generated in response to infection are directed to parasite epitopes. Thus the immune response that is induced is predominantly 'non-specific'. Interestingly, of the many functionally aberrant characteristics displayed by the immune system after infection with T.cruzi, polyclonal B- and T-cell non-specific responses and immunosuppression have not been sufficiently considered so far in the context of vaccination strategy and design. This Chapter is specifically aimed at addressing these questions and will attempt to outline new insights into the immunoresponses to parasites that have been provided by our recent findings.
Additional chapters from this book:
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Impact of Polyclonal Lymphocyte Responses on Parasite Evasion and Persistence
Paola Minoprio
In the field of immunoparasitology it is generally accepted that the survival and degree of pathogenicity of parasites is inextricably linked to their ability to escape and resi...
Ca2+ Signaling in the Invasion of Mammalian Cells by Trypanosoma cruzi
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The Role of Nitric Oxide in the Pathogenesis of Trypanosoma cruzi Infection
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This Chapter summarizes the roles of nitric oxide (NO) in mediating and controlling the effector immune response against Trypanosoma cruzi and in the pathology resulting from the infect...
