Considering that cAMP production triggered by A2B receptor is important to the inhibition of CD40 in L. amazonensis-infected DC, that this effect is not present in infection by other species of Leishmania (34) and that CD40 plays a central role in the activation of T lymphocytes by DC (8), we evaluated the expression of CD40 on DC from ears and draining lymph nodes of mice infected by L. amazonensis, in the presence or absence PSB1115, an A2B receptor antagonist. The gene discussed is CD40; the disease is infection.