Figure 3.

TLR-2 expression increases upon infection. (A) Western blot shows a time-dependent increase in TLR-2 expression by THP-1 MDMs after infection with L. donovani parasite. The blots below show siRNA-mediated KD of TLR-2 and reduced induction of Bcl-2 protein in TLR-2 KD macrophages. Blots are representative of three independent experiments. The bar graph alongside shows slightly reduced parasite uptake by TLR-2 KD THP-1 MDMs. Next placed are the immunofluorescence photomicrographs showing enhanced expression of macrophage TLR-2 receptors at 12 and 24 h post infection. (B) Blot shows increased TLR-2 expression by hMDMs upon L. donovani infection. The blot below shows infection-induced Bcl-2 expression was diminished in TLR-2 KD hMDMs. Ld, Leishmania donovani; KD, knockdown; Scr, scrambled siRNA. Blots are representative of three independent experiments. The adjacent bar graph shows a significant reduction in the parasite uptake by TLR-2 KD hMDMs. A minimum of 200 cells were counted. Data are mean ± SEM (n = 3). *P ≤ 0.05; Mann–Whitney test. (C) Blot shows a time-dependent increase in TLR-2 protein in mPM post infection. Unlike peritoneal macrophages from WT animals, no significant increase in the expression of Bcl-2 protein was observed in TLR-2 KO mPMs in response to infection. Blots in this figure are representative of at least 3–4 experiments. The adjacent bar graph shows that mPMs obtained from TLR-2 KO mice show significantly lesser uptake of parasites as compared to macrophages obtained from WT animals. The parasite uptake was measured by counting average number of internalized parasites per macrophage 3 h postinfection. WT, wild type; KO, knockout. Data are mean ± SEM (n = 3); *P ≤ 0.05; Mann–Whitney test.