Vaccine Development for Chagas Disease

Abstract

Experimenal vaccines against T. cruzi infection have only been assayed in murine laboratory models and, up to a limited scale, in animals reservoirs (dogs and guinea pigs) subjected to natural, vector-delivered infection. A paradox of the immune response in T. cruzi infection is: How is it maintained in the chronic phase so strongly as to provide protection against a re-infection but at the same time so inefficiently as not to clear the first infection? Studies on vaccine development should address the challenging question of how to boost or redirect the chronic immune response to recognize and eliminate the persistent parasites. This review addresses the immune mechanisms involved in protection, describing the cell populations and their effector functions, where gamma-interferon production prevails. The generation of DNA vaccines, and of T. cruzi targeted-deletion mutants and their assay in animal models of T. cruzi infection are promising research directions, now under intense development. Alternative methods of treatment and prevention seemed, in past decades, to render vaccines unnecessary. However, the growing spread of insecticide-resistant vectors and the lack of efficient, non toxic drugs for Chagas disease indicate that the search for efficient vaccines is well justified