HTCC as a Polymeric Inhibitor of SARS-CoV-2 and MERS-CoV.

Among seven coronaviruses that infect humans, three (SARS-CoV, MERS-CoV, and the newly identified SARS-CoV-2) are associated with a severe, life-threatening respiratory infection and multiorgan failure. We previously proposed that the cationically modified chitosan, N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (HTCC) is a potent inhibitor of HCoV-NL63. Next, we demonstrated the broad-spectrum antiviral activity of the compound, as it inhibited all low pathogenic human coronaviruses (HCoV-NL63, HCoV-229E, HCoV-OC43, and HCoV-HKU1). Here, using in vitro and ex vivo model of human airway epithelium, we show that HTCC effectively blocks MERS-CoV and SARS-CoV-2 infection. We also confirmed the mechanism of action for these two viruses, showing that the polymer blocks the virus entry to the host cell by interaction with the S protein.IMPORTANCE The beginning of 2020 brought us information about the novel coronavirus emerging in China. Rapid research resulted in the characterization of the pathogen, which appeared to be a member of the SARS-like cluster, commonly seen in bats. Despite the global and local efforts, the virus escaped the health care measures and rapidly spread in China and later globally, officially causing a pandemic and global crisis in March 2020. At present, different scenarios are being written to contain the virus, but the development of novel anticoronavirals for all highly pathogenic coronaviruses remains the major challenge. Here, we describe the antiviral activity of previously developed by us HTCC compound, which may be used as a potential inhibitor of currently circulating highly pathogenic coronaviruses - SARS-CoV-2 and MERS-CoV.