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 copyright holder for this preprint . https://doi.org/10.1101/2020.04. 13.20060467 doi: medRxiv preprint through antibody binding at each dilution was curve-fitted in order to estimate the dilution leading to a 50% inhibition of pseudotype replication ( ). A second metric is the degree of fit of the datapoints from the dilution series to the predicted sigmoid curve using for fitting, 205 expressed as R 2 . Samples showing non-specific blocking of entry (ie. non-concentration dependent) will show a low R 2 value. Of the 7 positive control samples, 6 possessed detectable neutralising ability, above the range seen in the pre-pandemic samples, and good is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.