Pretreatment with Cry1Ac Protoxin Modulates the Immune Response, and Increases the Survival ofPlasmodium-Infected CBA/Ca Mice

Abstract

Malaria is a major global health problem that kills 1-2 million people each year. Despite exhaustive research, naturally acquired immunity is poorly understood. Cry1A proteins are potent immunogens with adjuvant properties and are able to induce strong cellular and humoral responses. In fact, it has been shown that administration of Cry1Ac protoxin alone or with amoebic lysates induces protection against the lethal infection caused by the protozoaNaegleria fowleri. In this work, we studied whether Cry1Ac is able to activate the innate immune response to induce protection againstPlasmodium bergheiANKA (lethal) andP. chabaudiAS (nonlethal) parasites in CBA/Ca mice. Treatment with Cry1Ac induced protection against bothPlasmodiumspecies in terms of reduced parasitaemia, longer survival time, modulation of pro- and anti-inflammatory cytokines, and increased levels of specific antibodies againstPlasmodium. Understanding how to boost innate immunity toPlasmodiuminfection should lead to immunologically based intervention strategies.