PGE₂ and BALF have antiapoptotic and antiinflammatory effects on BMNs. (A) AnnexinV⁺ BMNs were measured by flow cytometry after addition of vehicle or BALF in the presence of AH6809 (an EP2 antagonist), AH23848 (an EP4 antagonist), or anti–IL-6 antibody. (B) PGE₂ concentration of BALF (left) and % of annexin V⁺ cells among CD11b⁺ Ly6G⁺ neutrophils in lung (right) from 5 mg/kg NS398- or vehicle-treated mice via intratracheal instillation. (C) ROS production of BMNs with or without PGE₂ pretreatment 30 minutes before PMA stimulation. Vehicles for PGE₂ and PMA are distilled water (DW) and dimethyl sulfoxide (DMSO), respectively. (D-E) Inflammatory cytokine release following LPS stimulation of BMNs in the presence or absence of PGE₂ (D) or BALF (E). (F) Tgm2 expression from BALF- or PGE₂-treated BMNs with or without PKA inhibitor H89. (G) Inflammatory cytokine release from BALF- or PGE₂-treated BMNs with or without H89 pretreatment 12 hours before LPS challenge. Dotted line indicates LPS only. (H) Cytokine release from BMNs from WT or Tgm2^−/− mice following LPS stimulation. (I) Inflammatory cytokine release from BMNs from WT or Tgm2^−/− mice pretreated with BALF from WT or Tgm2^−/− mice. Data are shown as mean ± standard error of the mean. Significant differences are denoted as *P < .05; **P < .01; ***P < .001; ****P < .0001. ns, not significant (two-way ANOVA) (A-B, C [right], D-I). % of max scale of each channel is presented as a percentage of maximum count (C).