(d) Luciferase activity in Jurkat cells transfected as in a, then exposed to medium alone (Med), wild-type E. coli (JM101), or JM101 E. coli mutants lacking both Omp C and Omp F (HN705) or lacking either OmpC (ΔOmpC) or OmpF (ΔOmpF). Data are representative of at least three independent experiments (error bars (a), s.d.). 