Splenocytes are the major source of IFN-γ ex vivo. B6 mice were either infected with 4,000 sporozoites of P. yoelii (n = 10 mice) or received an injection of salivary gland extracts from non-infected mosquitoes (n = 10 NiSG control mice). Five days later, splenocytes and iHLs were isolated and cultured for 3 days without any stimulation. Then, supernatants were collected and IFN-γ concentrations were determined by ELISA. A. Results are expressed as mean values ± SD of IFN-γ in pg per 2.5 × 105 cells. B. Results are expressed as mean values ± SD of IFN-γ in ng per organ (meaning per total number of splenocytes or iHLs at the indicated days p.i.). Data from a representative experiment out of two are shown.