Fig. 3.

Elevated expression of CatE is associated with impaired phagosome clearance and bactericidal activity in RNase-L^−/− macrophages. (A) Steady-state expression of CatE mRNA in macrophages +/− BA infection was determined by qRTPCR; values are normalized to constitutively expressed GAPDH mRNA. (B) Decay of CatE mRNA was quantified by qRTPCR after transcriptional arrest in WT and RNase-L^−/− macrophages. (C) LAMP 1/2, CatE, and α-actin proteins in WT and RNase-L^−/− macrophages were measured by Western blot. Right shows densitometric quantitation of LAMP1/2 signals normalized to α-actin; blot shown is representative of 3 independent experiments. (D) Peritoneal macrophages from WT and RNase-L^−/− mice were infected with E. coli for the indicated times, and the percentage reduction in viable bacteria as compared with the 1 hour value is shown (percentage killing); macrophages from 4 separate mice were analyzed in 2 independent experiments; the mean percentage killing +/− standard error is shown. *, P < 0.05. (E) At the indicated times after infection with E. coli (2.5 × 10³ cfu), cells in the peritoneal fluid were isolated and stained; representative fields are shown at ×200 and ×400 (Inset).