FIG 1.
Anti-PfCelTOS IgG antibody levels in vaccine mouse sera at different time points by an ELISA. Groups of 6- to 8-week-old female BALB/c mice were immunized subcutaneously with recombinant PfCelTOS alone or formulated with different adjuvants (MPL, CpG, QS-21, and MCQ [MPL/CpG/QS-21]). Anti-PfCelTOS IgG antibody levels were compared between the sera collected from different immunized mouse groups on day 10, day 24 (10 days after the first boost), and day 38 (10 days after the second boost) after the first immunization. The individual mouse serum samples were incubated in duplicate wells with 1:200-diluted sera for 90 min. There was a significant difference in total IgG antibody levels between different immunization time points in vaccine groups (P < 0.05 by a paired-sample t test). The bars and error bars show the mean OD490 values and standard deviations (SD) for 16 individual mice in each group, respectively. The ELISA cutoffs were calculated as the mean OD490 of preimmune mouse sera (as the negative controls; n = 30) plus 3 SD. The cutoffs for IgG on days 10, 24, 38, and 180 after the first immunization were an OD490 of 0.1 each. Ag, PfCelTOS antigen.