No evidence for basigin/CD147 as a direct SARS-CoV-2 spike binding receptor

The spike protein of SARS-CoV-2 is known to enable viral invasion into human cells through direct binding to host receptors including ACE2. An alternate entry receptor for the virus was recently proposed to be basigin/CD147. These early studies have already prompted a clinical trial and multiple published hypotheses of the role of this host receptor in viral infection and pathogenesis. We sought to independently characterize the basigin-spike protein interaction. After conducting several lines of experiments, we report that we are unable to find evidence supporting the role of basigin as a putative spike-binding receptor. Recombinant forms of both the entire ectodomain and S1 domain of the SARS-CoV-2 spike protein that directly bind ACE2 do not interact with basigin expressed on the surface of human cells. Using specialized assays tailored to detect receptor interactions as weak or weaker than the proposed basigin-spike binding, we report no evidence for direct binding of the viral spike to either of the two common isoforms of basigin. Given the pressing need for clarity on which targets of SARS-CoV-2 may lead to promising therapeutics, we present these findings to allow more informed decisions about the translational relevance of this putative mechanism in the race to understand and treat COVID-19.