LAMININ RECEPTOR IN LEUKOCYTES

白细胞穿透基底机制的研究进展 膜显示兔腹膜渗出细胞(PMN)优先 使用层粘连蛋白，基底膜的主要成分，附着在 另一种成分是IV型胶原蛋白。PMN在化学上也对 层粘连蛋白的纳摩尔水平。我们现在已经确定PMN拥有一个 层粘连蛋白受体。使用I125-层粘连蛋白的Scatchard分析表明 单类可饱和高亲和力结合位点(kd=6.15nM/L) PMN和每个小区3.6 x 10,000个站点。胰凝乳酶衍生片段 对于层粘连蛋白，保留了细胞结合位点的C1也得到了类似的结果。 抗层粘连蛋白的单抗用于免疫过氧化物酶的研究 受体提示PMN细胞表面存在该受体。PMN 对纳摩尔水平的C1和层粘连蛋白做出化学反应，结果 与绑定数据的辅音。中性粒细胞对甲酰肽的趋化作用是 明显地被单抗抑制，表明 层粘连蛋白受体可能是中性粒细胞趋化所必需的。我们的 结果表明，中性粒细胞通过基底膜的外渗是有帮助的。 通过细胞与基质中的层粘连蛋白的可逆性附着和通过 对可溶的、完整的和可能降解的层粘连蛋白的趋化作用。 这些特征与高转移性肿瘤有许多共同之处。 肿瘤细胞。

Previous studies on the mechanism of leukocyte traversal of basement membranes showed that rabbit peritoneal exudate cells (PMN) preferentially used laminin, a major constituent of basement membrane, to attach to another component, type IV collagen. PMN also responded chemotactically to nanomolar levels of laminin. We have now determined that PMN possess a receptor for laminin. Scatchard analysis using I125-laminin indicate a single class of saturable high affinity binding sites (kd = 6.15 nM/L) on PMN and 3.6 x 10,000 sites per cell. A chymotryptically derived fragment of laminin, C1 which retains the cell binding site gave similar results. Immunoperoxidase studies using monoclonal antibodies to the laminin receptor indicated the presence of the receptor on PMN cell surfaces. PMN responded chemotactically to nanomolar levels of C1 and laminin, a result consonant with binding data. PMN chemotaxis to a formyl peptide was markedly inhibited by the monoclonal antibodies, suggesting that the laminin receptor may be required for PMN chemotaxis in general. Our results suggest that PMN extravasation across basement membranes is aided both by reversible attachment of the cells to laminin in the matrix and by chemotaxis to a gradient of soluble intact and possibly degraded laminin. These characteristics have much in common with those of highly metastatic tumor cells.