Fisher E S, Lauffenburger D A
Biophys J. 1987 May;51(5):705-16. doi: 10.1016/S0006-3495(87)83397-0.
The process by which cells encounter their targets is the first step of a number of cell functions involved in the immune response, such as cell-mediated cytotoxicity and phagocytic ingestion of foreign material. In many instances, this encounter may be rate-limiting, and therefore it is important to understand what factors influence the encounter rate. One key aspect of cell-target encounter is the motility behavior of the cell in the vicinity of a target. This movement may be entirely random, or there may be a directed, or chemotactic, component to it. In this paper we focus on the effects of cell motility properties, and particularly the chemotactic directional bias, on the rate of cell-target encounter. Specifically, we derive an expression for the mean encounter time of cells that meet targets in two dimensions as a function of the cells' directional orientation bias. We show that a modest degree of bias can reduce the mean encounter time by orders of magnitude, while nearly perfect directional bias offers little additional benefit. We illustrate the application of these results to a particular example system: alveolar macrophages removing inhaled particles and bacteria from the lung surface.
细胞与靶标相遇的过程是免疫反应中许多细胞功能的第一步，例如细胞介导的细胞毒性和对外来物质的吞噬摄取。在许多情况下，这种相遇可能是限速步骤，因此了解哪些因素影响相遇速率很重要。细胞与靶标相遇的一个关键方面是细胞在靶标附近的运动行为。这种运动可能完全是随机的，或者可能存在定向或趋化成分。在本文中，我们关注细胞运动特性，特别是趋化方向偏差对细胞与靶标相遇速率的影响。具体而言，我们推导了二维空间中细胞与靶标相遇的平均相遇时间作为细胞方向取向偏差函数的表达式。我们表明，适度的偏差可以将平均相遇时间降低几个数量级，而近乎完美的方向偏差几乎没有额外的益处。我们将这些结果应用于一个特定的示例系统：肺泡巨噬细胞从肺表面清除吸入的颗粒和细菌。
