Bacteriophage Qβ virus-like particles displaying Chikungunya virus B-cell epitopes elicit high-titer E2 protein antibodies but fail to neutralize a Thailand strain of Chikungunya virus.

Chikungunya virus (CHIKV) is a mosquito-borne virus associated with arthritis and musculoskeletal pains. More than 2.9 million people worldwide have been infected with the virus within the last 1.5 decades; currently, there are no approved vaccines to protect against CHIKV infection. To assess the potential of using CHIKV peptides as vaccine antigens, we multivalently displayed CHIKV peptides representing B-cell epitopes (amino acids 2800-2818, 3025-3058, 3073-3081, 3121-3146, and 3177-3210), from E2 glycoprotein (Singapore strain), on the surface of a highly immunogenic bacteriophage Qβ virus-like particle (VLP). We assessed the immunogenicity of CHIKV E2 amino acid 3025-3058 (including the other epitopes) displayed on Qβ VLPs in comparison to the same peptide not displayed on VLPs. Mice immunized with the E2 peptides displayed on Qβ VLPs elicited high-titer antibodies compared with the group immunized just with the peptide. However, sera from immunized mice did not neutralize CHIKV AF15561 (isolated from Thailand). The data suggest that Qβ VLPs is an excellent approach to elicit high-titer CHIKV E2-protein antibodies at a lower dose of antigen and future studies should assess whether Qβ-CHIKV E2 aa 2800-2818 VLPs and Qβ-CHIKV E2 aa 3025-3058 VLPs can neutralize a Singapore Strain of CHIKV.