Hyde D M, Downey G P, Tablin F, Rosengren S, Giclas P C, Henson P M, Worthen G S
Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206, USA.
Am J Physiol. 1997 Mar;272(3 Pt 1):L471-8. doi: 10.1152/ajplung.1997.272.3.L471.
Diminished ability of neonatal neutrophils to orient and move in a chemotactic gradient has been linked to compromised pulmonary host defense. We investigated whether deficiency of neonatal neutrophil function in vitro was evident in acute pulmonary inflammation. Analysis of neutrophils in vitro showed impaired chemotaxis in 4-wk-old compared with adult rabbits. In vivo-directed migration of labeled neutrophils into the alveolar space of adult rabbits in response to C5f instillation was significantly less for neutrophils donated from 4-wk-old rabbits compared with those from adults. In contrast, there were no differences in the alveolar accumulation of 4-wk-old and adult labeled neutrophils in 4-wk-old rabbits in response to C5f instillation, although the response showed a shorter time course than seen in adult rabbits. Adult rabbits diverted 46% of the blood away from the right cranial lung lobe, whereas 4-wk-old rabbits showed no change in blood flow after C5f instillation. Megakaryocytes (a source of blood flow mediators) were 3.2-fold greater in adult compared with 4-wk-old lung. These data suggest that the lack of blood flow diversion from inflamed neonatal lung increases neutrophil migration into alveoli, allowing for preservation of an inflammatory response despite neutrophil deficiencies in chemotaxis.
新生儿中性粒细胞在趋化梯度中定向和移动的能力减弱与肺部宿主防御受损有关。我们研究了在急性肺部炎症中，新生儿中性粒细胞功能缺陷在体外是否明显。体外对中性粒细胞的分析表明，与成年兔相比，4周龄兔的趋化性受损。与成年兔捐献的中性粒细胞相比，4周龄兔捐献的中性粒细胞对C5f滴注的体内定向迁移到成年兔肺泡腔的能力明显降低。相比之下，在4周龄兔中，4周龄和成年标记中性粒细胞对C5f滴注的肺泡积聚没有差异，尽管其反应的时间进程比成年兔短。成年兔将46%的血液从右颅肺叶分流，而4周龄兔在C5f滴注后血流没有变化。与4周龄兔肺相比，成年兔肺中的巨核细胞（血流介质的来源）多3.2倍。这些数据表明，炎症新生儿肺缺乏血流分流会增加中性粒细胞向肺泡的迁移，尽管中性粒细胞趋化性存在缺陷，但仍能维持炎症反应。
