Immune responses in mice immunized with rPvMSP8, rPvMSP1-19, or rPvMSP8+1. (A) IgG levels in rPvMSP8-, rPvMSP1-19-, and rPvMSP8+1-immunized mice. IgG was detected at day 7 postimmunization, and the levels increased throughout the whole immunization period. Antigen specificity was confirmed using preimmune serum samples as controls. (B) Data are presented as the geometric mean OD obtained at different concentrations, expressed as the reciprocal of the serum dilution obtained from mice immunized with rPvMSP8, rPvMSP1-19, or rPvMSP8+1 (dilutions from 1:10,000 to 1:5,120,000). Numbers on the x axis indicate the dilutions tested. (C) Avidity of anti-rPvMSP8 IgG antibodies to rPvMSP8 or rPvMSP8+1 antigen. (D) Avidity of anti-rPvMSP1-19 IgG antibodies to rPvMSP1-19 or rPvMSP8+1 antigen. (E) Avidity of anti-rPvMSP8+1 IgG antibodies to rPvMSP8, rPvMSP1-19, or rPvMSP8+1 antigen.