Figure 3: Protein expression in L. infantum episomally transfected promastigotes during the exponential phase of development (a) Western blot analysis of His-tagged proteins detected in whole cell lysate. Equal amounts of total protein (35  𝜇 g) were resolved by electrophoresis in 4–12% gradient gels (Invitrogen), blotted, and developed with anti-HisTag antibody followed by ECL (Amersham). Gene ID and the theoretical molecular weight of detected proteins are listed in order in Table 1. (b) Identification of secreted proteins in whole cell lysate (Lys) and concentrated cell-free culture supernatant (CCFS) obtained from promastigotes incubated for 6 hours in serum-free medium. Note the absence of 𝛽 Tubulin in the concentrated supernatant of Line 8. Nontransfected L. infantum promastigotes (Wild Type) were used as a negative control. Protein molecular mass standards in kDa are shown on the left of each panel.