Bovine RSV F ELISA

A semi-quantitative bRSV F antibody detection ELISA kit (CER Group, Belgium, Cat. No. K.BRSVsero) was used to determine the amount of anti-bRSV F antibodies in serum. Half of the plates were coated with an anti-bRSV F monoclonal antibody (mAb) (CER Groupe, Belgium, Cat. No. IMM-COM-MON-002) and incubated with bRSV (strain RB94⁵⁰) produced by virus culture on Vero monolayer cells (bRSV + ). The second half of the plate consisted of control wells (bRSV−) with mAb coating but no bRSV, to correct for serum non-specific binding. Serum diluted 1:100 was added to the plates and bound anti-bRSV antibodies were detected with a peroxidase labeled anti-bovine IgG conjugate and revealed with the enzyme substrate tetramethybenzidine. Plates were read at 450 nm and the signal of each bRSV− well subtracted from that of the corresponding bRSV + well. In parallel to unknown serum samples, a positive control consisting of a reconstituted freeze-dried bRSV antibody was run on each plate and used to normalize sample results. According to the normalized value for each sample, results were expressed on a zero to ++++ scale.