Tamatani T, Kitamura F, Kuida K, Shirao M, Mochizuki M, Suematsu M, Schmid-Schönbein G W, Watanabe K, Tsurufuji S, Miyasaka M
Department of Immunology, The Tokyo Metropolitan Institute of Medical Science, Japan.
Eur J Immunol. 1993 Sep;23(9):2181-8. doi: 10.1002/eji.1830230920.
We have characterized the rat LECAM-1 (L-selectin) by the use of newly generated hamster anti-rat LECAM-1 monoclonal antibodies (mAb) (HRL1, HRL2, HRL3, HRL4), with respect to the biochemistry, cellular distribution and function, and developed an ELISA system to detect the soluble form of rat LECAM-1. In the rat, lymphocyte and neutrophil LECAM-1 have apparent molecular masses of 65 and 62 kDa, respectively, and differential glycosylation may account for the molecular heterogeneity. Readily detectable levels of LECAM-1 are expressed on peripheral blood lymphocytes and neutrophils, but not on thymocytes. Lymphocyte LECAM-1 is rapidly shed from the cell surface upon cell activation with PMA, but not with interleukin (IL)-8. In contrast, neutrophil LECAM-1 showed rapid shedding upon stimulation with phorbol 12-myristate 13-acetate (PMA) or IL-8. Concomitantly there is up-regulated expression of Mac-1 in PMA- and IL-8-stimulated neutrophils. Neutrophil rolling in mesenteric venules was significantly inhibited by administration of function-blocking anti-rat LECAM-1 mAb HRL3, but not by non-blocking HRL4, indicating that LECAM-1 plays a significant role in leukocyte rolling. Given that LECAM-1 is rapidly shed from the cell surface, we attempted to develop an ELISA system for detecting LECAM-1 is soluble form, and measured the levels in experimental autoimmune uveitis. The circulating levels of LECAM-1 increased from day 4, which preceded the appearance of clinical signs of uveitis and remained high until uveitis subsided, suggesting that soluble LECAM-1 is potentially a useful parameter to monitor certain types of inflammatory or immune disorders.
我们利用新制备的仓鼠抗大鼠LECAM-1单克隆抗体（mAb）（HRL1、HRL2、HRL3、HRL4），从生物化学、细胞分布和功能方面对大鼠LECAM-1（L-选择素）进行了特性分析，并开发了一种ELISA系统来检测大鼠LECAM-1的可溶性形式。在大鼠中，淋巴细胞和中性粒细胞的LECAM-1的表观分子量分别为65 kDa和62 kDa，糖基化差异可能是分子异质性的原因。外周血淋巴细胞和中性粒细胞上可轻易检测到LECAM-1的表达水平，但胸腺细胞上没有。淋巴细胞LECAM-1在用佛波酯（PMA）激活细胞后会迅速从细胞表面脱落，但用白细胞介素（IL）-8激活则不会。相反，中性粒细胞LECAM-1在用佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）或IL-8刺激后会迅速脱落。同时，在PMA和IL-8刺激的中性粒细胞中，Mac-1的表达上调。给予功能阻断性抗大鼠LECAM-1 mAb HRL3可显著抑制肠系膜小静脉中的中性粒细胞滚动，但非阻断性mAb HRL4则无此作用，这表明LECAM-1在白细胞滚动中起重要作用。鉴于LECAM-1会迅速从细胞表面脱落，我们试图开发一种ELISA系统来检测LECAM-1的可溶性形式，并测量实验性自身免疫性葡萄膜炎中的水平。LECAM-1的循环水平从第4天开始升高，这早于葡萄膜炎临床症状的出现，并一直保持在高位直至葡萄膜炎消退，这表明可溶性LECAM-1可能是监测某些类型炎症或免疫疾病的有用参数。
