Intranasal delivery of replicating mRNA encoding neutralizing antibody against SARS-CoV-2 infection in mice

Jia-Qi Li,Han-Qing Ye,Zhe-Rui Zhang,Qiu-Yan Zhang,Xiao-Dan Li,Ya-Nan Zhang,Cheng-Lin Deng,Bo Zhang,Xiang-Yue Zeng,Hong-Qing Zhang

doi:10.1038/s41392-021-00783-1

Abstract

The lung is the prophylaxis target against SARS-CoV-2 infection, and neutralizing antibodies are a leading class of biological products against various infectious viral pathogen. In this study, we develop a safe and cost-effective platform to express neutralizing antibody in the lung with replicating mRNA basing on alphavirus replicon particle (VRP) delivery system, to prevent SARS-CoV-2 infections. First, a modified VEEV replicon with two subgenomic (sg) promoters was engineered to translate the light and heavy chains of antibody simultaneously, for expression and assembly of neutralizing anti-SARS-CoV-2 antibody CB6. Second, the feasibility and protective efficacy of replicating mRNA against SARS-CoV-2 infection were demonstrated through both in vitro and in vivo assays. The lung target delivery with the help of VRP system resulted in efficiently block SARS-CoV-2 infection with reducing viral titer and less tissue damage in the lung of mice. Overall, our data suggests that expressing neutralizing antibodies in the lungs with the help of self-replicating mRNA could potentially be a promising prophylaxis approach against SARS-CoV-2 infection.

Highlights

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the ongoing pandemic of COVID-19, which has caused the hospitalization and deaths of millions of individuals worldwide
We explored the feasibility of using Venezuelan equine encephalitis virus (VEEV) replicon, a replicating mRNA, encoding both the heavy and light chains for antibodies expression, to prevent SARS-CoV-2 respiratory infection by VEEV replicon particles (VRPs) delivery through nasal route
BHK-21 cells neutralizing antibody expression, we evaluated the efficacy were transfected with replicon of VEEV-Rep-CB6, and the expression and assembly of CB6 monoclonal antibodies (mAbs) in transfected cells was demonstrated by indirect immunofluorescence assay (IFA) using the goat anti-human IgG (H + L) conjugated with Alexa FluorTM

Summary

RESULTS

To express the heavy and light chains of the neutralizing mAb SRAS-CoV-2 as antigen (Fig. 2c), implying the assembly and simultaneously in one VEEV replicon vector, a modified version of secretion of CB6 antibody. Monoclonal neutralizing anti-SARS-CoV-2 antibody, named CB6, was used as the candidate sequence of mAb in our study.[13] The Functional in vitro validation of VEEV-VRP-CB6 against SARS-CoV-2 coding sequences of the heavy and light chains of CB6 were under infection in cell culture control of two independent sg promoters (Fig. 1a), respectively for After demonstrating the ability of VEEV-VRP-CB6 to deliver neutralizing antibody expression (VEEV-Rep-CB6). BHK-21 cells neutralizing antibody expression, we evaluated the efficacy were transfected with replicon of VEEV-Rep-CB6, and the expression and assembly of CB6 mAb in transfected cells was demonstrated by indirect immunofluorescence assay (IFA) using the goat anti-human IgG (H + L) conjugated with Alexa FluorTM of VEEV-VRP-CB6 to block SARS-CoV-2 infection (Fig. 3). The lung of mice increasing IFA positive cells of CB6 mAb and VEEV nsP1 were We examined the delivery ability of VEEV-VRP-CB6 in vivo for observed within VRP-infected cells at 24 h post-infection (hpi) with neutralizing antibody expression in the respiratory tract of mouse. Our results indicate that such nose-to-lung delivery of VRP encoding SARS-CoV-2 specific neutralizing mAb could forestall viral infection from the outset

DISCUSSION

Findings

MATERIALS AND METHODS