It could bind strongly to the S1 subunit or RBD in the S protein of SARS-CoV-2, but did not block binding of the S1 or RBD to the receptor ACE2, suggesting that GRFT inhibits SARS-CoV-2 infection through a mechanism of action different from most SARS-CoV-2 neutralizing antibodies that neutralize SARS-CoV-2 infection by blocking interaction between viral RBD and receptor ACE2 [17]. Here, ACE2 is linked to COVID-19.