Figure 1From: Roles of virulence genes (PsaA and CpsA) on the invasion of Streptococcus pneumoniae into blood systemMorphological changes of THP-1 and A549 cells after Streptococcus pneumoniae (SP) infection. THP-1 and A549 cells began to die after infection at 4 to 8 hours: A) THP-1 at 0 hours; B) THP-1 at 4 hours; C) THP-1 at 8 hours; D) A549 at 0 hours; E) A549 at 4 hours; F), A549 at 8 hours. (×200).Back to article page