Figure 5.

The proliferative responses to concanavalin A (Con A)- and parasite VF- and Em2-antigen stimulation of spleen cells from non-infected (white bars), infected wild type (WT) (black bars) and infected inducible nitric oxide synthase-knockout (iNOS-KO) mice (striped bars) were determined at different time-points [1 and 4 months postinfection (p.i.)]. The figure shows results from one representative out of four independent experiments exhibiting similar results. The suppression of concanavalin A (Con A)-derived proliferation at an early stage was repeated in four independent experiments, with comparable results obtained. *, †, ‡ and § indicate statistically significant differences. The results were calculated as the mean counts per minute (c.p.m.) of quadruplicate wells and expressed as geometric mean minus background (Δc.p.m.), where background = c.p.m. of wells containing pulsed but unstimulated cells.