Schagat Trista L, Wofford Jessica A, Greene Kelly E, Wright Jo Rae
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
Am J Physiol Lung Cell Mol Physiol. 2003 Jan;284(1):L140-7. doi: 10.1152/ajplung.00125.2002. Epub 2002 Aug 30.
Surfactant protein A (SP-A), a pulmonary lectin, plays an important role in regulating innate immune cell function. Besides accelerating pathogen clearance by pulmonary phagocytes, SP-A also stimulates alveolar macrophage chemotaxis and directed actin polymerization. We hypothesized that SP-A would also stimulate neutrophil chemotaxis. With the use of a Boyden chamber assay, we found that SP-A (0.5-25 microg/ml) did not stimulate chemotaxis of rat peripheral neutrophils or inflammatory bronchoalveolar lavage (BAL) neutrophils isolated from LPS-treated lungs. However, SP-A affected neutrophil chemotaxis toward the bacterial peptide formyl-met-leu-phe (fMLP). Surprisingly, the effect was different for the two neutrophil populations: SP-A reduced peripheral neutrophil chemotaxis toward fMLP (49 +/- 5% fMLP alone) and enhanced inflammatory BAL neutrophil chemotaxis (277 +/- 48% fMLP alone). This differential effect was not seen for the homologous proteins mannose binding lectin and complement protein 1q but was recapitulated by type IV collagen. SP-A bound both neutrophil populations comparably and did not alter formyl peptide binding. These data support a role for SP-A in regulating neutrophil migration in pulmonary tissue.
表面活性蛋白A（SP-A）是一种肺凝集素，在调节先天性免疫细胞功能中发挥重要作用。除了加速肺吞噬细胞清除病原体外，SP-A还能刺激肺泡巨噬细胞趋化性和定向肌动蛋白聚合。我们推测SP-A也会刺激中性粒细胞趋化性。通过使用Boyden小室试验，我们发现SP-A（0.5 - 25微克/毫升）不会刺激大鼠外周血中性粒细胞或从经脂多糖处理的肺中分离出的炎症性支气管肺泡灌洗（BAL）中性粒细胞的趋化性。然而，SP-A会影响中性粒细胞对细菌肽甲酰甲硫氨酸亮氨酸苯丙氨酸（fMLP）的趋化性。令人惊讶的是，对于这两种中性粒细胞群体，其作用不同：SP-A降低外周血中性粒细胞对fMLP的趋化性（单独fMLP时为49±5%），并增强炎症性BAL中性粒细胞的趋化性（单独fMLP时为277±48%）。对于同源蛋白甘露糖结合凝集素和补体蛋白1q，未观察到这种差异效应，但IV型胶原可重现这种效应。SP-A与两种中性粒细胞群体的结合相当，且不会改变甲酰肽结合。这些数据支持SP-A在调节肺组织中中性粒细胞迁移方面的作用。
