Figure 1.

Production of IFN-γ after 24 h co-culture of human PBMCs with P. falciparum-infected erythrocytes is dependent on parasite strain. For 24 h, 5 × 10⁵ human PBMCs were stimulated with 2·5 × 10⁷ erythrocytes infected with one of four laboratory strains of P. falciparum (TM284, R29, HB3, Palo Alto) across a range of parasitaemias. The IFN-γ level in the culture supernatants was measured by ELISA. Across 11 donors (see Figure S1 for data from five additional donors), the IFN-γ response after PBMC stimulation with P. falciparum is significantly dependent on parasite strain (F_3,178 = 48·49, P < 0·001). Error bars show the standard error about the mean of at least duplicate wells for each data point.