Project description:Mucosal immunity plays a pivotal role in providing comprehensive protection against upper-airway infections and effectively limiting the shedding and transmission of SARS-CoV-2. Despite its critical importance, there remains a notable absence of nasal spray vaccines endorsed for global use by the World Health Organization. This could be due to the inability of current intranasal vaccines to induce strong mucosal and systemic responses in humans, thus urgently entailing a next-generation of intranasal COVID-19 vaccines with novel and safe technologies. In this study, we prepared a two-component intranasal vaccine that combines adenovirus vectors with a self-assembled subunit protein. Specifically, the adenovirus vector expresses the spike protein of XBB.1.5 variant (Ad5XBB.1.5), and were mixed with the recombinant protein that developed derived from the receptor binding domain (RBD) of XBB.1.5 (RBDXBB.1.5-HR). Combination of Ad5XBB.1.5 and RBDXBB.1.5-HR elicited superior humoral and cellular immunity against XBB.1.5-included variants compared with the individual components. Importantly, the STING signaling pathway was found to be crucial for the adjuvant effect of the adenovirus vector. In addition, to increase the broad-spectrum neutralizing capacities, a trimeric protein derived from the BA.5 variant (RBDBA.5-HR) was incorporated to formulate a three-component vaccine (Ad5XBB.1.5+RBDXBB.1.5-HR+RBDBA.5-HR), indicating the utilization of a combination of an adenovirus-vectored and subunit protein vaccines has the potential to serve as a next-generation intranasal vaccine platform. Of note, intranasally delivery of two-component vaccine provided protective immunity against live Omicron XBB.1.16 virus challenge in mice. Furthermore, the combination of adenovirus and subunit protein vaccine demonstrates excellent tolerability and safety in human subjects, and is able to induce enhanced mucosal immunity as well as high levels of sera neutralizing antibody in all participants. These findings underscore its suitability for clinical application in the prevention of SARS-CoV-2 variants encompassing XBB lineages.
Project description:We generated LNP-mRNA encoding B.1.1.529 SARS-CoV-2 spike, and intramuscularly administered it in a human IgG and IgK knock-in mouse. Single cell VDJ-seq unveiled the sequences of human monoclonal antibodies targeting the B.1.1.529 SARS-CoV-2 spike protein.
Project description:Coronavirus disease 2019 (COVID-19) has brought about a great threat to global public health. Recently, a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant B.1.1.529 has been reported in South Africa and induced a rapid increase in COVID-19 cases. On November 24, 2021, B.1.1.529 named Omicron was designated as a variant under monitoring (VUM) by World Health Organization (WHO). Two days later, the Omicron variant was classified as a variant of concern (VOC). This variant harbors a high number of mutations, including 15 mutations in the receptor-binding domain (RBD) of spike. The Omicron variant also shares several mutations with the previous VOC Alpha, Beta, and Gamma variants, which immediately raised global concerns about viral transmissibility, pathogenicity, and immune evasion. Here we described the discovery and characteristics of the Omicron variant, compared the mutations of the spike in the five VOCs, and further raised possible strategies to prevent and overcome the prevalence of the Omicron variant.