Beneficial effects of CDP-CHO PEP are not recapitulated by its precursors. Effect of treating mice infected with H1N1 influenza A/WSN/33 (10,000 pfu/mouse) with choline, CTP (cytidine triphosphate), or choline + CTP (all 100 μg/mouse, i.p., daily) daily from 1 to 5 d.p.i. on (A) carotid SaO2 (percentage) and (B) lung water content (wet:dry weight) at 6 d.p.i. n ≥ 5/group. All data were analyzed by ANOVA with a Tukey-Kramer multiple comparison post hoc test and are presented as mean ± SEM. #P < 0.001 versus mock-inoculated mice.