Comparison of CD80 level on dendritic cells in acute lung injury mice

Introduction

Dendritic cells (DC) may play an important role in acute lung injury (ALI) [1]. CD80 is the crucial co-stimulatory molecule that is expressed on the surface of DCs. However, little is known about the expression of CD80. The purpose of this study was to observe the expression of CD80 on circulating, lung and splenic dendritic cells (DC) in ALI mice.

Methods

Twelve C57BL/6 mice were randomly divided into two groups: control group and ALI group. Blood, lungs and spleens were harvested at 6 hours after LPS or PBS administration. The level of CD80 on DC was assessed by flow cytometry (FCM). The IL-6 level in the lung was measured by enzyme-linked immunosorbent assay. Lung wet weight/ body weight (LW/BW) was recorded to assess lung injury. Meanwhile, pathological changes were examined under an optical microscope.

Results

LPS-ALI resulted in a significant increase in lung W/D ratio. Histologically, widespread alveolar wall thickening caused by edema, severe hemorrhage in the interstitium and alveolus, and marked and diffuse interstitial infiltration with inflammatory cells were observed in the ALI group. Meanwhile, the levels of IL-6 in lung tissue were significantly enhanced in the LPS-induced ALI mice. FCM analysis showed that the level of CD80 on circulating DC in control group was (3.3 ± 1.5)%, CD80 expression on lung DC was (3.6 ± 1.2)%, and expression of CD80 on splenic DC was (9.0 ± 3.6)%, which was significantly higher than that on circulating DC and lung DC ( P < 0.05). In the ALI mouse, the level of CD80 on peripheral blood DC was (5.1 ± 2.1)%; the CD80 level on lung DC was (9.6 ± 2.50)%, which was significantly higher than that on peripheral blood DC (P < 0.05); and the level of CD80 on splenic DC was (25.2 ± 4.7)%, which was significantly higher than CD80 levels on the peripheral blood and lung DC (P < 0.05). The CD80 level on lung and splenic DC in ALI mice was significantly higher than that on lung and splenic DC in control mice (P < 0.05 vs. Con).

Conclusion

There is a dynamic characteristic in the expression of CD80 on DC populations in normal and ALI mice. Elevated expression of CD80 on DC seems to play an important role in the pathogenesis of ALI.