Fig. 1: Influenza A virus induces monocyte apoptotic cell disassembly in vitro and in vivo.

a THP1 monocytes were exposed to UV irradiation or infected with PR8, and imaged by DIC microscopy 3 and 24 h post treatment, respectively. Primary human CD14⁺ monocytes were infected with PR8 and imaged by DIC microscopy b or subjected to flow cytometry 24 h p.i. c. ApoBD formation index = number of A5⁺ ApoBDs/number of A5⁺ apoptotic cells. d THP1 monocytes were infected with PR8, and the percentage of NP/HA and A5-positive cells was determined by flow cytometry. e THP1 monocytes were infected with PR8-GFP and GFP expression was monitored by confocal microscopy, 24 h p.i. f B6 mice were administered PBS or 1000 pfu PR8 and BAL cells harvested 3 days p.i., stained with Hoechst and monitored by confocal microscopy (representative of n = 3 independent repeats). g Schematic diagram of a mouse IAV infection model. The total number of A5-positive mouse monocytes h and monocyte ApoBDs i within the BAL were quantified by flow cytometry under the following infection conditions; PBS, 10,000 pfu X31 and 100, 1000, or 10,000 pfu PR8 at either day 3 or day 5 p.i., error bars represent SEM (n = 9 mice). Unless otherwise specified, all in vitro data are representative of at least three independent experiments where error bars represent SEM of n = 3 biological repeats, *P < 0.05, **P < 0.01, ***P < 0.001, unpaired Student’s two-tailed t-test.