Comparison between HeLa-M2 and NP ELISAs. A. Purified murine MAbs 14C2-S1-4 (anti-M2e, closed circles) and L39-17 (anti-NP, open circles) were tested by ELISA for binding to HeLa-M2 and NP immunosorbents, respectively. Bound MAbs were detected in parallel assays by the same procedure (187-biotin/streptavidin-peroxidase/OPD). Each symbol shows mean OD ± SEM of triplicates. The data are representative of several independently performed assays. B. Five human control sera were tested at various dilutions in ELISA against HeLa-M2, NP and the corresponding control immunosorbents. Bound Abs were detected in parallel assays by the same procedure (biotinylated goat-anti-human cκ,λ/streptavidin-peroxidase/OPD). M2-specific (closed symbols) and NP-specific binding (open symbols) are expressed as Δ ODs. Symbols show means of duplicates. One of two independent assays is shown.