Mice produce antibodies binding the M1H5 and M2B10 neutralizing epitopes whether immunized with ACT (A) or RTX985 (B). Sera at a 1:200 dilution were incubated on ELISA plates coated with ACT, before addition of 0.1 nm M2B10, M1H5, or M1F11 as a competitor. After incubation, immobilized monoclonal antibody was detected with anti-human Fc-HRP, with absorbance normalized to wells without sera. Lower absorbance indicates a higher concentration of epitope-specific murine antibodies.