Changes in phagocytotic and microbial killing capabilities of swine alveolar macrophages (AMs). Changes in (A) phagocytotic and (B) microbial killing capabilities in PCV2- and/or PRRSV-inoculated swine alveolar macrophages (AMs) were determined by using Candida albicans as the target. Following 60 min of incubation and staining with acridine orange, the percentages of viable AMs with engulfed yeasts and killed yeasts were determined. Data are expressed as the level different from that of the mock-inoculated AMs (Mock) and shown as mean ± SD of three independent experiments. PCV2: AMs inoculated with PCV2 alone; PRRSV: AMs inoculated with PRRSV alone; PCV2/PRRSV: AMs inoculated with PCV2 first then inoculated with PRRSV 18 h later; PRRSV/PCV2: AMs inoculated with PRRSV first then inoculated with PCV2 18 h later; PCV2-PRRSV: AMs co-inoculated with PCV2 and PRRSV simultaneously. * (P < 0.05), ** (P < 0.01), *** (P < 0.001)The difference between the two treatment groups at the same h post inoculation (HPI) with the first virus is statistically significant. aValues are significantly different from the Mock at the same h post inoculation (HPI) with the first virus.