Differential immune activation profile of SARS-CoV-2 and SARS-CoV infection in human lung and intestinal cells: implications for treatment with IFN-β and IFN inducer

Shuai, Huiping; Chu, Hin; Hou, Yuxin; Yang, Dong; Wang, Yixin; Hu, Bingjie; Huang, Xiner; Zhang, Xi; Chai, Yue; Cai, Jian-Piao; Chan, Jasper Fuk-Woo; Yuen, Kwok-Yung

OBJECTIVES: Respiratory and intestinal tract were two primary target organs of SARS-CoV-2 infection. However, detailed characterization of the host-virus interplay in infected human lung and intestinal epithelial cells is lacking. METHODS: We utilized immunofluorescence assays, flow cytometry, and RT-qPCR to delineate the virological features and the innate immune response of the host cells against SARS-CoV-2 infection in two prototype human cell lines representing the human pulmonary (Calu3) and intestinal (Caco2) epithelium when compared with SARS-CoV. RESULTS: Lung epithelial cells were significantly more susceptible to SARS-CoV-2 compared to SARS-CoV. However, SARS-CoV-2 infection induced an attenuated pro-inflammatory cytokines/chemokines induction and type I and type II IFN responses. A single dose of 10 U/mL IFN-β (IFNβ) pretreatment potently protected both Calu3 and Caco2 against SARS-CoV-2 infection. Interestingly, SARS-CoV-2 was more sensitive to the pretreatment with IFNβ and IFN inducer than SARS-CoV in Calu3. CONCLUSIONS: Despite robust infection efficiency in both the human lung and intestinal epithelial cells, SARS-CoV-2 could attenuate the virus-induced pro-inflammatory response and IFN response. Pre-activation of the type I IFN signaling pathway primed a highly efficient antiviral response in the host against SARS-CoV-2 infection, which could serve as a potential therapeutic and prophylactic maneuver to COVID-19 patients.