Neutralising antibodies to SARS coronavirus 2 in Scottish blood donors - a pilot study of the value of serology to determine population exposure

Craig Thompson; Nicholas Grayson; Robert Paton; José Lourenço; Bridget Penman; Lian Ni Lee; Valerie Odon; Juthathip Mongkolsapaya; Senthil Chinnakannan; Wanwisa Dejnirattisai; Matthew Edmans; Alexander Fyfe; Carol Imlach; Kreepa Kooblall; Nicholas Lim; Chang Liu; Cesar Lopez-Camacho; Carol-Anne McInally; Narayan Ramamurthy; Jeremy Ratcliff; Piyada Supasa; Beibei Wang; Alexander J Mentzer; Marc Turner; Calum Semple; John Kenneth Baillie; Heli Harvala; Gavin Screaton; Nigel Temperton; Paul Klenerman; Lisa Jarvis; Sunetra Gupta; Peter Simmonds

The specificity of both assays is potentially influenced by cross-reactivity with other human 290 coronaviruses, including the respiratory viruses, OC43 and HKUI in the Betacoronavirus genus that circulate in winter months. Some previous studies have indicated an absence of reactivity of negative control sera against the SARS-CoV-1 spike protein in ELISA and the high specificity of assays based on the spike protein compared to those using the more conserved nucleoprotein or whole virus 18 . SARS-CoV-2 spike protein is likely to share this 295 specificity. Existing data on neutralising antibodies indicates that assay specificity may be even greater; although both SARS-CoV-1 and -2 enter cells through the ACE-2 receptor [19] [20] [21] , and possess structurally similar spike proteins 20,22-24 , it has recently been demonstrated that neutralising monoclonal antibodies (MAbs) against SARS-CoV-1 infection bound but did not neutralise SARS-CoV-2 25 , Conversely, MAbs raised against SAR-CoV-2 showed little or no 300 cross-neutralisation of SARS-CoV-1 26,27 . However, cross-reactivity is most unlikely to cause an assay specificity problem, as SARS-CoV-1 has never spread significantly in the UK or elsewhere in Europe 28 .