Table 2.

Biological effects of the various bacterial strains on CHO cells

StrainEffector(s)% Altered morphologya% Trypan blue stainedaDecreased viabilityb
None (uninfected)6 ± 20NAc
PA103ExoT, ExoU53 ± 253 ± 2+
PA103exoT::TcExoU46 ± 846 ± 8+
PA103toxA::Ωd ExoT, ExoUNDe ND+
PA103ΔexoU ExoT98 ± 20
PA103ΔexoUexoT::TcNone6 ± 20
PA103exsA::ΩNoneNCf 0
PA103ΔexoUexoT::Tc pUCPNone 50
PA103ΔexoUexoT::Tc pUCPexoS ExoS90 ± 30
PA103ΔexoUexoT::Tc pUCPexoSE381AExoSE381A99 ± 10
PA103ΔexoUexoT::Tc pUCPexoT ExoT990
PA103ΔexoUexoT::Tc pUCPexoY ExoY95 ± 60
PA103ΔexoUexoT::Tc pUCPexoYK81MExoYK81M7 ± 40
  • a Percentage of CHO cells displaying an altered morphology or trypan blue staining via phase-contrast microscopy; results are averaged from photomicrographs taken of three random fields of infected monolayers.

  • b Presence or absence of a significant reduction in cell viability compared to uninfected control cells by an MTT viability assay.

  • c NA, not applicable; uninfected control cells were used as the basis of comparison for the MTT assay.

  • d Control for the MTT assay; a strain used to show that exotoxin A does not mediate the acute cytotoxic response in this tissue culture model.

  • e ND, not done.

  • f NC, no change in cellular morphology relative to the uninfected control.