An indirect sandwich enzyme labelled immunosorbent assay for the detection of foot and mouth disease virus immunizing antigen in tissue culture harvests

The optimum conditions for an indirect sandwich enzyme-linked immunosorbent assay for foot and mouth disease virus 140S antigen assay are described. Factors which could contribute to the variation in the test were investigated and a calibration coefficient for the conversion of ELISA values to antigen concentration in micrograms of 140S antigen per millilitre was calculated. Antigen mass in nine tissue culture harvests was estimated and these correlated well with estimates made by sucrose density gradients (r = 0.95).