We were recently contacted by researchers at the Pasteur Institute of Beijing (Ruichen Wei, Qiben Leng) who were grappling with an out break of Hand-Foot-Mouth Disease, a serious infection caused by enterovirus 71 (EV71) among other viruses. They were interested identifying T cell epitopes, so as to begin to develop an epitope-based vaccine. We applied the iVAX technology to identify promiscuous CD4+ T cell epitopes contained within the sequence of the EV71 polyprotein. Fifteen epitopes were identified, and three of them were dominant ones. The most dominant epitope was highly conserved among enterovirus species, including HFMD-related coxsackieviruses, HFMD-unrelated echoviruses and polioviruses. Our findings seem to suggest that CD4+ T cell responses to poliovirus following vaccination, or to other enteroviruses to which individuals may be exposed in early childhood, may have a modulating effect on subsequent CD4+ T cell response to EV71 infection.
This would be yet another example of the importance of analyzing cross-reactive T cell epitopes – what is present in one virus may also be present in another, contributing to immunodominance