%0 Journal Article
%A Srivastava, Simran
%A Kumar, Sahil
%A Mishra, Suman
%A Rajmani, Raju S
%A Singh, Randhir
%A Dutta, Somnath
%A Ringe, Rajesh Prakash
%A Varadarajan, Raghavan
%D 2026
%F open:3207
%I American Chemical Society (ACS)
%J ACS Infect. Dis.
%K SARS-CoV-2; coronavirus; efficacy; lyophilized; preparedness; protein-subunit; thermostability; yield
%N 1
%P 104-118
%T Development of a thermostable and broadly neutralizing pan-sarbecovirus vaccine candidate
%U http://crdd.osdd.net/open/3207/
%V 12
%X Zoonotic spillover of sarbecoviruses to humans resulted in the SARS-CoV-1 outbreak in 2003 and the current COVID-19 pandemic caused by SARS-CoV-2. In both cases, the viral spike protein (S) is the principal target of neutralizing antibodies that prevent infection. Within the spike, the immunodominant receptor-binding domain (RBD) is the primary target of neutralizing antibodies in COVID-19 convalescent sera and vaccine recipients. We have constructed stabilized RBD derivatives of different sarbecoviruses: SARS-CoV-1 (Clade 1a), WIV-1 (Clade 1a), RaTG13 (Clade 1b), RmYN02 (Clade 2), and BtKY72 (Clade 3). Stabilization enhanced yield by 3-23-fold. The RBD derivatives were conformationally intact, as assayed by binding to multiple broadly neutralizing antibodies. The stabilized RBDs show significant enhancement in apparent Tm, exhibit resistance to a 2-h incubation at temperatures up to 60 °C in PBS in contrast to the corresponding WT RBDs, and show prolonged stability of over 15 days at 37 °C after lyophilization. In mice immunizations, both stabilization and trimerization significantly enhanced elicited neutralization titers by �100-fold. The stabilized RBD cocktail elicited highly neutralizing titers against both homologous and heterologous pseudoviruses. The immunogenicity of the vaccine formulation was assessed in both na\"\ive and SARS-CoV-2 preimmunized mice, revealing an absence of immune imprinting, thus indicating its suitability for use in future sarbecovirus-origin epidemics or pandemics.
%Z Copyright of this article belongs to ACS.