The well-evolved pathogen.

Stan Falkow looked at the world with his eyes peering from the outer membrane of a gram-negative bacterium. It was a great vantage point from which to dream about the possible superpowers these organisms might have. He mused about these dreams with his trainees who sometimes found through rigorous scientific exploration that the superpowers really were there! Stan also realized that bacterial pathogenesis by definition was a two-way street, and that masterful understanding of bacterial virulence factors also required a masterful understanding of host cell processes against which the virulence factors were deployed. In my own scientific journey, I have sought to explore bacterial-host interactions that result in subtle alterations of the host's adaptive immune response. Here, as an example, I describe an interaction between Chlamydia trachomatis and host T cells that may contribute to the establishment of persistent infection.