Confocal images of B cells infected with mycobacteria. The actin filaments were labelled with rhodamine-phalloidin and the bacteria were stained with fluorescein isothiocyanate (FITC). a) M. smegmatis (MSM) infection caused evident actin rearrangements within 1 h of infection; a mycobacterium was observed attached to the cell. b-c) After 3 h of infection with MSM, intracellular bacteria were observed (b) and long actin filaments were evident (c). d) M. tuberculosis (MTB) infection induced actin reorganisation after 1 h of infection, and bacilli attached to the cells were observed; e-f) B cells, after 3 h of infection with MTB, presented actin cytoskeletal changes in cells without any adhered or intracellular bacteria.