Scanning electron micrographs of B cells infected with mycobacteria or S. typhimurium (ST) or treated with phorbol 12-myristate 3-acetate (PMA). a-b) Non-infected B cells. c-d) PMA-treated B cells, which exhibit abundant long, thin, and wide membrane extensions that resemble filopodia (thin arrows) and lamellipodia (wide arrows). e-f) B cells infected with M. smegmatis (MSM) show abundant membrane filopodia (thin white narrows) and lamellipodia formation (wide white narrows) and attached bacilli that are trapped by the membrane projections (black arrows). g-h) Mycobacterium tuberculosis (MTB)-infected B cells show membrane ruffling (white arrow) and some bacilli bound to the cell (black arrows). i-k) S. typhimurium-infected B cells show filopodia (thin white arrows) and lamellipodia formation (wide white arrows). The white arrowheads depict attached bacilli and a bacillus that is surrounded by forming lamellipodia.