Pleiotropic Effect of Hormone Insulin-Like Growth Factor-I in Immune Response and Pathogenesis in Leishmaniases

Figure 3

Parasitism and nitric oxide production in L. infantum-infected cells upon extrinsic IGF-I stimulus. THP-1 cells (a–c) or BALB/c mouse bone marrow-derived macrophages (d–f) were infected with L. infantum promastigotes and stimulated with recombinant IGF-I (rIGF-I, 50 ng/mL; R&D Systems, USA) for 24 and 48 hours. One representative experiment from three independent assays is shown. THP-1 cells were differentiated into macrophages with 20 ng/mL phorbol 12-myristate 13-acetate (PMA; Sigma-Aldrich, USA) for 24 hours. Then, the cells were washed and allowed to rest in a fresh medium for 48 hours before infection with L. infantum promastigotes. The parasitism (median number of parasites per 100 cells), nitric oxide production (Griess Reagent), and arginase activity (urea production) were determined after 24 and 48 hours of incubation.

(a)

(b)

(c)

(d)

(e)

(f)