Phenotypic analyses CD44hi T-cells.

<p>(A) Gating strategy. After lymphocytes gating based on forward-scatter (FSC) and side-scatter (SSC) properties, CD4+ and CD8+ T cells were selected. Total memory T cells were gated based on high CD44 expression. T cells with effector memory (T_EM) and central memory (T_CM) phenotype were identified based on CD62L expression. (B) CD8+CD44hi and CD4+CD44hi T-cell pool at day 40 post-immunization with high or lose dose. Composition of the CD8+CD44hi and CD4+CD44hi T-cell pool was assessed in the liver (left panel), spleen (central panel) or PBMC (right panel) of mice immunized by high and low dose of RAS or CPS. Results are from 2 independent experiments (n_RAS = 10; n_CPS = 10; n_naïve = 13) and cells from individual mice assayed. Error bars represent standard error of the mean (SEM). * = p<0.05, ** = p<0.005, *** = p<0.0001.</p

Sporozoite and blood-stage specific IgG.

<p>Plasma were collected from mice immunized by RAS or CPS before (C-1) and 6 to 21 days after (C+6; C+21) challenge. Levels of anti-sporozoite or anti-blood-stage IgG antibodies were determined by ELISA (n_RAS = 5; n_CPS = 5; n_naïve = 9). Error bars represent standard error of the mean (SEM). ** = p<0.005, *** = p<0.0001.</p

Re-exposure by sporozoite challenge increases memory CD8+ T cell response.

<p>Levels of CD8+ T_EM were measured before (C-1) and after (C+21) challenge at 3, 6 or 9 months after RAS and CPS immunization (A) – individual values for each time point and median are plotted. IFNγ response by hepatic CD8+CD44hi T cells was measured by intracellular staining before (C-1) and after (C+21) challenge at 3, 6 or 9 months post-immunization (B) – error bars represent SEM. * = p<0.05, ** = p<0.005, *** = p<0.0001.</p

Declined specific IFNγ response by hepatic CD8+ memory T cells over time.

<p>Sporozoite specific IFNγ response by hepatic CD8+CD44hi T cells was measured by intracellular staining at 3 months post-immunization (A) – individual values and median are plotted. Longevity of the specific (sporozoites) and non-specific (PMA/Ionomycin) IFNγ response was further assessed 6 and 9 months after immunization (B) – error bars represent SEM. * = p<0.05, ** = p<0.001.</p

CD4+ and CD8+ T_EM cells in response to challenge.

<p>Changes in the effector memory CD8+ and CD4+ T-cell compartment from the liver, spleen and PBMC of mice immunized with low dose of RAS (n = 15) or CPS (n = 12) were evaluated at various time-points around challenge (C-1, C+6, C+21). Results are from 3 independent experiments (n_naïve = 18) and cells from individual mice assayed. Error bars represent standard error of the mean (SEM). * = p<0.05, *** = p<0.0001.</p

Demographic information.

<p>Demographic information.</p

Protection and prepatent period after heterologous NF135.C10 challenge.

<p><b>Left panels:</b> Kaplan-Meier curves showing percentage of thick smear negative volunteers after NF135.C10 challenge according to previous NF54 protection status (A) and NF54 CPS-immunization dose (C). <b>Right panels:</b> The corresponding distribution of prepatent period of thick smear positive volunteers is shown in dot plots according to NF54 protection status (B) and NF54 CPS-immunization dose (D). Lines represent medians. ⨂ = Volunteer presumptively treated after NF54 challenge and considered NF54 protected.</p