Journal: BMC Microbiology
Article Title: IRAK-M alters the polarity of macrophages to facilitate the survival of Mycobacterium tuberculosis
doi: 10.1186/s12866-017-1095-2
Figure Lengend Snippet: IRAK-M over-expression resulted in higher bacterial load, while IRAK-M interference resulted in lower bacterial load in M. tb infected cells. Lentiviruses that over-expresses (IRAK-M-GFP-Lentivirus, OE) or interferes with (IRAK-M-RNAi-GFP-Lentivirus, KD) IRAK-M expression, were constructed. a Lentiviruses of negative control (NC) and OE were introduced into Jurkat cells. Cells were examined by light microscope and fluorescent microscope at 96 h post-transfection. More than 80% of Jurkat cells expressed GFP (200×, scale bar 50 μm). b Lentiviruses of NC and KD were introduced in U937 cells. Cells were examined by light microscope and fluorescent microscope at 96 h post-transfection. More than 90% of U937 cells expressed GFP (200×, scale bar 100 μm). c Expression of IRAK1-4 in Jurkat and U937 cells was evaluated by Western blot. d - g Bacterial load in Jurkat ( d , e ) and U937 cells ( f , g ) challenged with virulent M. tuberculosis H37Rv strain (MOI 10) were analyzed by acid-fast staining and colony forming units (CFU). Cells were infected with lentivirus for 96 h, challenged with H37Rv for 5 h and washed three times with PBS. d , f At 24 h post-infection, 1 × 10 6 cells were resuspended in 20 μl PBS and fixed in 4% para-formaldehyde for 15 min on the slides. Acid-fast staining (AF) was performed and arrows indicated AF-positive bacteria in the cells (1000×, scale bar 10 μm). e , g For determination of CFU, at 5 and 24 h post-infection, 1 × 10 5 cells were washed aseptically, homogenized and plated at 10-fold serial dilutions on Middlebrook 7H11 agar. CFU numbers per plate were counted to evaluate the bacterial load 3 to 4 weeks later. The bacterial load in cells of different groups was expressed as Log10 CFU ± SEM (**, p < 0.01; ***, p < 0.001)
Article Snippet: Human monocytic leukemia line U937 (ATCC® CRL-1593.2) and human T-cell acute lymphoblastic leukemia line Jurkat (ATCC® TIB-152TM) were cultured at 37 °C in CO 2 incubator (CCL-170B-8, ESCO, Singapore) in RPMI-1640 medium, supplemented with 10% fetal bovine serum, 100 U/ml penicillin and 100 μg/ml streptomycin.
Techniques: Over Expression, Infection, Expressing, Construct, Negative Control, Light Microscopy, Microscopy, Transfection, Western Blot, Staining, Bacteria