Fig 2. Assessment of anti-SARS CoV-2 antibody levels in mink sera.

Panel A. Anti-SARS-CoV-2 antibody titres were measured by ELISA. Selected sera from mink collected at the time of initial diagnosis (blue circles), at free-testing (grey circles) and following re-infection (red circles), on 19-08-20, 05-10-20 and 06-11-20 respectively, that scored positive when assayed undiluted were titrated and assayed again by ELISA. The reciprocals of the highest dilution yielding a positive signal are plotted (on a log2 scale). Mean (+/- SEM) values are indicated by horizontal black lines. Panel B. The same serum samples were also assayed in virus neutralization assays and the calculated antibody titres are plotted (on a log2 scale) using the same colour scheme. The statistical significance of the differences between anti-CoV-2 antibody levels was determined using the Kruskal-Wallis test (see Materials and Methods).