Effects of anti-PAFR antibody on PAI-1 expression by PA103-infected cells. In (A), a representative agarose gel shows the expression of PAI-1 and β-actin mRNA transcripts in control and infected A549 cells pretreated or not with the anti-PAFR antibody, assessed by semiquantitative RT-PCR. In (B), mean ± SD values of the ratio of PAI-1 to β-actin transcript densities obtained in 2 RT-PCR assays carried out in duplicate. In (C), mean values ± SE of PAI-1 concentration in cell supernatants from control and infected cultures, pretreated (anti-PAFR +) or not (anti-PAFR -) with the anti-PAFR antibody, obtained in three different assays carried out in quintuplicate. *** p < 0,001 when the results from PA103-infected cells pretreated with anti-PAFR antibody were compared with those from untreated cells or when data obtained from PA103-infected cells were compared with those from controls or from PA103ΔexoU-infected cells.