Fig. 1: Two-dose challenge to test for protection by CSP, P36, and P52 antigens.

a BALB/cJ mice were gene gun primed with DNA encoding the Py circumsporozoite protein (CSP)/P36 protein/P52 protein at days 0 and 2, and were subjected to two-dose challenge followed by blood smears to evaluate for sterile protection. Control group mice received empty vector DNA (VD) immunization via gene-gun, and/or a dose of Py-RAS, or CSP DNA immunization via gene-gun alone, and then were subjected to Py-WT challenge. b Sterile protection outcomes for controls and CSP, P36, and P52 immunized groups. c BALB/cJ mice were either (i) gene gun primed with DNA encoding the CSP protein at days 0 and 2 or (ii) gene gun primed with DNA encoding the CSP protein at day 0, and were subjected to two-dose challenge followed by blood smears to evaluate for sterile protection. d Sterile protection outcomes for control and Py-CSP-immunized groups. VD control group mice protection data acquired from panel b for comparison. e For P36/P52 and CSP co-administration studies, mice were gene gun primed on day 0 with a single cartridge of CSP and one or two cartridges of P36/P52, received two-dose challenge followed by blood smears. Sterile protection outcomes for CSP and P36 (f), CSP and P52, and CSP, P52 and P36 studies (g) compared with CSP protection data from panel d, and P36 or P52 protection data from panel b. h. BALB/cJ mice were gene gun primed 28 days earlier with CSP and P36 or CSP and P52 and were subjected to two-dose challenge. They were injected with CD8 depletion antibodies at indicated days followed by blood smears to evaluate for sterile protection. i. Protection data of CD8⁺ T cells depleted mice groups compared with protection data from panels f, g. N ≤ 5 mice/group for panels a–g. Data compiled from two or more independent experiments. N = 5 mice/group for panels h and i. Data were analyzed by Fisher Exact test: P < 0.05 is considered significant. *P < 0.05, **P < 0.01, ***P < 0.001 ****P < 0.0001. VD, vector DNA (control).