Evidence of cross-stage CD8+ T cell epitopes in malaria pre-erythrocytic and blood stage infections.

Malaria parasites have a complex, multistage life cycle and there is a widely held view that each stage displays a distinct set of antigens presented to the immune system. Yet, molecular analysis of malaria parasites suggests that many putative antigenic targets are shared amongst the different stages. The specificities of these cross-stage antigens and the functions of the immune responses they elicit are poorly characterized. It is well-known that CD8+ T cells play opposing immune functions following Plasmodium berghei (Pb) infection of C57BL/6 mice. Whilst these cells play a crucial role in protective immunity against pre-erythrocytic stages, they are implicated in the development of severe disease during blood stages. Recently, CD8+ T cell epitopes derived from proteins supposedly specific for either pre-erythrocytic or blood stages have been described. In this brief report, we have compiled and confirmed data that the majority of the mRNAs and/or proteins from which these epitopes are derived display expression across pre-erythrocytic and blood stages. Importantly, we provide evidence of cross-stage immune recognition of the majority of these CD8+ T cell epitopes. Hence, our findings provide a resource to further examine the relevance of antigen-specific cross-stage responses during malaria infections.