4.1.3.2  Rational: Serum from convalescent SARS patients is able to neutralize SARS-CoV2 efficiently
Antiserum that contains antibodies against human ACE2 could hinder the entry of both SARS-S and SARS-2-S pseudotypes while not affected the entry of VSV-G and MERS-S pseudotypes. It supports the notion that SARS-S and SARS-2-S utilize the same primary entry receptor, i.e., ACE2, which is different from the primary receptors VSV-G and MERS-S engage for cell entry that is LDLR and DPP4, respectively.
Sera from three convalescent SARS patients reduced the SARS-S entry and, to e lesser degree, the SARS-2-S entry. The patient serum effect was in a dose-dependent manner [16].