Neutralizing-antibody-independent SARS-CoV-2 control correlated with intranasal-vaccine-induced CD8 + T cell responses.

Effective vaccines are essential for the control of the coronavirus disease 2019 (COVID-19) pandemic. Currently developed vaccines inducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S)-antigen-specific neutralizing antibodies (NAbs) are effective, but the appearance of NAb-resistant S variant viruses is of great concern. A vaccine inducing S-independent or NAb-independent SARS-CoV-2 control may contribute to containment of these variants. Here, we investigate the efficacy of an intranasal vaccine expressing viral non-S antigens against intranasal SARS-CoV-2 challenge in cynomolgus macaques. Seven vaccinated macaques exhibit significantly reduced viral load in nasopharyngeal swabs on day 2 post-challenge compared with nine unvaccinated controls. The viral control in the absence of SARS-CoV-2-specific NAbs is significantly correlated with vaccine-induced, viral-antigen-specific CD8 ⁺ T cell responses. Our results indicate that CD8 ⁺ T cell induction by intranasal vaccination can result in NAb-independent control of SARS-CoV-2 infection, highlighting a potential of vaccine-induced CD8 ⁺ T cell responses to contribute to COVID-19 containment.
Competing Interests: H.I., K.K., R.S., and T.M. are the inventors on Patent Cooperation Treaty (PCT) application for SeV-NME vaccine. The authors declare no other competing interests.
(© 2022 The Author(s).)