Table 3. CD25hi Depletion Assay Results.
| Malaria Antigen Poolb | Schistosoma Antigen Poolb | ||||||||
| Cohorta | Season | IL-2 (%) | Mean %c (range) | IFN-γ (%) | Mean %c (range) | IL-2 (%) | Mean %c (range) | IFN-γ (%) | Mean %c (range) |
| SP no Mal | Wet | 0/3 (0) | - | 0/3 (0) | - | 0/3 (0) | - | 1/3 (33) | - |
| Dry | 0/3 (0) | - | 0/3 (0) | - | 0/3 (0) | - | 0/3 (0) | - | |
| SP Mal | Wet | 4/15 (27) | 0.51(0.31–0.83) | 6/15 (40) | 0.27 (0.05–1.0) | 2/15 (13) | 0.39 (0.17–0.61) | 3/15 (20) | 0.39 (0.08–0.84) |
| Dry | 4/14 (29) | 0.3 (0.05–0.57) | 7/14 (50) | 0.13 (0.05–0.49) | 3/14 (21) | 0.27 (0.05–0.72) | 3/14 (21) | 0.30 (0.05–0.77) | |
| SN Mal | Wet | 5/13 (38) | 0.3 (0.05–1.23) | 4/13 (31) | 0.21 (0.05–0.56) | n/a | - | n/a | - |
| Dry | 6/14 (43) | 0.21 (0.05–0.56) | 4/14 (29) | 0.16 (0.13–0.23) | n/a | - | n/a | - | |
Results of enhanced cytokine expression to antigenic stimulation after CD25hi depletion of PBMC followed by antigenic stimulation in comparison to mock-depleted populations. The numerator represents the number of children with enhanced Interleukin 2 (IL-2) or Interferon-gamma (IFN-γ) expression after depletion compared to mock-depletion. The denominator is the number of children examined. The net percentage of cytokine expressed in CD3+CD4+CD8− T cells (i.e., depletion results minus mock-depletion results) after depletion as measured by multiparameter flow cytometry is also depicted in those experiments with significant cytokine expression increase. Cells were acquired from age-matched children aged 4–14 years with or without S. haematobium during the malaria transmission (wet) season and again during a dry season follow-up visit. Also depicted are results from SP children who did not acquire malaria (SP no Mal) during the wet season.
Stratification between younger children aged 4–8 years and older children aged 9–14 years revealed no significant difference so results are reported as a combined age cohort of children aged 4–14 years.
PBMC were stimulated with a P. falciparum antigen pool (Apical Membrane antigen 1 and Merozoite Surface Protein 1) or with a S. haematobium antigen pool (soluble egg antigen and soluble worm antigen protein).
The mean percentage increase represents the average of the net increase in cytokine production (stimulant wells minus media wells) of those experiments with statistically significant results. Significance is defined by 1) net percentage of cytokine producing cells ≥0.05% in CD25hi-depleted compared to mock-depleted PBMC, 2) the number of positive events between depleted and mock-depleted cultures was significant by Chi-square analysis and 3) the number of positive events in the stimulant pool compared to the media control in depleted cultures was significantly increased.