Cytokine gene expression in PBMC from L. infantum experimentally infected dogs and healthy control dogs. PBMC were stimulated with soluble leishmanial antigen (SLA) from L. infantum and ConA. RNA isolation and QRT-PCR were performed after 24 hours of stimulation as described in Material and Methods. QRT-PCR data were analysed by using the 2−ΔCt method. The average of the mRNA levels of PBMC from three asymptomatic, four oligosymptomatic, four polysymptomatic and two control non-infected dogs are presented. Striped bars represent unstimulated PBMCs, black bars represent SLA and open bars represent ConA. A) IFNγ; B) TNF-α; C) IL-10; D) IL-18. Cytokine responses were examined in: 3 asymptomatic, 4 oligosymptomatic, 4 polysymptomatic dogs and 2 control dogs.