Mice Immunized with the Vaccine Candidate HexaPro Spike Produce Neutralizing Antibodies against SARS-CoV-2

Chotiwat Seephetdee, Nattawut Buasri, Kanit Bhukhai, Kitima Srisanga, Suwimon Manopwisedjaroen, Sarat Lertjintanakit, Nut Phueakphud, Chatbenja Pakiranay, Niwat Kangwanrangsan, Sirawat Srichatrapimuk, Suppachok Kirdlarp, Somnuek Sungkanuparph, Somchai Chutipongtanate, Arunee Thitithanyanont, Suradej Hongeng and Patompon Wongtrakoongate

Recently, a new version of prefusion spike trimers, named HexaPro, has been shown to possess two RBD in the “up” conformation, due to its physical property, as opposed to just one exposed RBD found in S-2P. Importantly, this HexaPro spike antigen is more stable than S-2P, raising its feasibility for global logistics and supply chain. Here, we report that the spike protein HexaPro offers a promising candidate for the SARS-CoV-2 vaccine. Mice immunized by the recombinant HexaPro adjuvanted with aluminum hydroxide using a prime-boost regimen produced high-titer neutralizing antibodies for up to 56 days after initial immunization against live SARS-CoV-2 infection. Also, the level of neutralization activity is comparable to that of convalescence sera. Our results indicate that the HexaPro subunit vaccine confers neutralization activity in sera collected from mice receiving the prime-boost regimen.

Reference:

Seephetdee C, Buasri N, Bhukhai K, Srisanga K, Manopwisedjaroen S, Lertjintanakit S, Phueakphud N, Pakiranay C, Kangwanrangsan N, Srichatrapimuk S, Kirdlarp S, Sungkanuparph S, Chutipongtanate S, Thitithanyanont A, Hongeng S, Wongtrakoongate P. Mice Immunized with the Vaccine Candidate HexaPro Spike Produce Neutralizing Antibodies against SARS-CoV-2. Vaccines (Basel). 2021 May 12;9(5):498. doi: 10.3390/vaccines9050498.

DOI: 10.3390/vaccines9050498