FIG 1.

Recognition of homologous P. falciparum NF54 sporozoites by CPS-induced antibodies. Homologous NF54 sporozoites were preincubated with 10% inactive complement and 10% heat-inactivated pre- or postimmunization serum from CPS-immunized volunteers (n = 16). (A and B) The amounts of CPS-induced IgG (A) and IgM (B) antibodies recognizing sporozoites were determined by flow cytometry and are shown as geometric mean fluorescence intensities (MFI). (C and D) Levels of IgG (C) and IgM (D) antibodies to CSP before (Pre) and after (Post) completed CPS immunization in CPS-immunized volunteers (n = 24) were determined by ELISAs and are shown as arbitrary units (AU), as defined by serial dilutions of a reference standard serum pool with high antibody concentrations. (E) CSP-specific IgG1 antibodies in pre- and postimmunization samples from CPS-immunized volunteers (n = 15) were determined by CSP-specific IgG1 subclass ELISAs and are shown as arbitrary units. Differences between pre- and postimmunization samples were determined by paired Student's t test, and a P value of <0.05 was considered statistically significant.