FIG. 3.

Effects of attachment of L. pneumophila to H. vermiformis and A. polyphaga on tyrosine phosphorylation of host proteins. (A) Cell extracts were prepared from uninfected H. vermiformis (lane 1), from H. vermiformis infected with L. pneumophila for 5 min (lane 2) or for 15 min (lane 3), or from uninfected cells incubated for 15 min (lane 4). Lane 5 represents samples prepared from H. vermiformis infected for 15 min followed by removal of extracellular bacteria and further incubation for 15 min. (B) Extracts were prepared from uninfected A. polyphaga (lane 1) or from A. polyphaga infected with L. pneumophila for 5 min (lane 2) or for 15 min (lane 3). Lane 4 represents samples prepared from infection with dead L. pneumophila. Western blots were probed with antiphosphotyrosine antibody (see Materials and Methods). Arrows indicate the position of the 170-kDa protein.