Subunit vaccine formulations based on recombinant envelope proteins of Chikungunya virus elicit balanced Th1/Th2 response and virus-neutralizing antibodies in mice

The recent resurgence of Chikungunya virus in India and Indian Ocean Islands with unusual clinical severity is a matter of great public health concern. Despite the fact that CHIKV resurgence is associated with epidemic of unprecedented magnitude, none of the vaccine candidate has been approved so far. The envelope protein E1 and E2 being the major immunodominant structural proteins with crucial role in virus attachment and entry, can prove to be potential vaccine candidates. In the present study, the immunogenic potential of bacterially expressed CHIKE1 and CHIKE2 recombinant proteins along with various adjuvants is reported. Assessment of the protective efficacy of both the vaccine formulations was further confirmed by both in vitro and in vivo neutralisation tests. Splenocytes from immunized mice, cultured in vitro when stimulated with the vaccine antigens revealed induction of very high levels of both pro- and anti- inflammatory cytokines indicating a balance of Th1 and Th2 response.