Internalization of a non-pathogenic mycobacteria by macropinocytosis in human alveolar epithelial A549 cells

Temporal Transcriptional Response during Infection of Type II Alveolar Epithelial Cells with Francisella tularensis Live Vaccine Strain (LVS) Supports a General Host Suppression and Bacterial Uptake by Macropinocytosis

“…Additionally, amiloride was not cytotoxic to the bacteria (data not shown). In further support of this mechanism, it had been previously published that other actin cytoskeleton inhibitors, such as cytochalasin D, also interfere with the uptake of Francisella into macrophages and A549 epithelial cells (31,62,64,65), supporting our results.…”

“…To further investigate this result, we performed experiments using a known actin rearrangement inhibitor, amiloride, which has been previously used to demonstrate macropinocytosis in A549 and other cell types (62,63). A549 epithelial cells preincubated with or co-incubated with amiloride showed greatly reduced F. tularensis LVS internalization (Fig.…”

“…To verify the process of macropinocytosis for F. tularensis LVS uptake, fluorescence microscopy experiments were performed using FITC-dextran, a large molecule that is known to be taken up in macropinosomes (62). A549 epithelial cells do not spontaneously take up FITC-dextran (Fig.…”

WASH drives early recycling from macropinosomes and phagosomes to maintain surface phagocytic receptors

“…Immature dendritic cells and macrophages both continuously take up their surrounding fluid by macropinocytosis to sample their environment and capture antigens for presentation (8). Unfortunately this process can provide a way for pathogens to gain entry into host cells and is thus exploited by a number of infectious agents such as viruses, bacteria, and even prions (9)(10)(11)(12)(13).…”

Relative Efficacy of Uptake and Presentation of Mycobacterium bovis BCG Antigens by Type I Mouse Lung Epithelial Cells and Peritoneal Macrophages

“…The lung epithelium is constantly exposed to airborne pathogens, and it is crucial that the local defense mechanisms rapidly clear infection and the attendant threat of a sustained inflammatory response. Several reports in the literature have shown the ability of lung epithelial cells to internalize pathogens and airborne particulate material, though these studies have generally been confined to lung epithelial cell lines (1,8,22,25). Epithelial cells, however, do not fall in the category of professional antigen-presenting cells (APCs), and as such, their relative efficacy as APCs is yet to be clearly defined.…”