Dogs with leishmaniasis exhibit limited specific-cellular immune response and increase in IL-10 production [34,47], to determine if blocking IL-10 signaling would revert Leishmania-specific lymphoproliferative unresponsiveness, CFSE labeled-PBMCs from healthy or infected dogs were cultured together with, or without, rcasIL-10R1, and with or without the addition of SLA, or in the presence of PHA alone for five days. The gene discussed is IL10; the disease is leishmaniasis.