Lowe Elizabeth P, Wei Duo, Rice Peter J, Li Chuanfu, Kalbfleisch John, Browder I William, Williams David L
Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614-0575, USA.
Am Surg. 2002 Jun;68(6):508-17; discussion 517-8.
Fungal cell wall glucans nonspecifically stimulate various aspects of innate immunity via interaction with membrane receptors on macrophages, neutrophils, and natural killer cells. We investigated the binding of water-soluble glucans in primary cultures of normal human coronary or dermal vascular endothelial cells (VECs). Membranes from VECs exhibited saturable binding. Competition studies demonstrated the presence of at least two glucan binding sites on VECs. Glucan phosphate competed for all binding sites with a KD of 3.7 microM for coronary VECs and 11 microM for dermal VECs, respectively. Laminarin, a low molecular weight glucan, competed for 47 to 51 per cent of binding (KD = 2.8-2.9 microM), indicating the presence of at least two binding sites. Glucan (1 microg/mL) stimulated VEC nuclear factor kappaB nuclear binding activity and Interleukin 8 expression--but not that of vascular endothelial growth factor--in a time-dependent manner. This is the first report of pattern recognition receptors for glucan on human VECs. It also provides the first evidence that glucans can directly modulate the functional activity of VECs by stimulating cytokine gene. These results provide new insights into the mechanisms by which the host recognizes and responds to fungal cell wall products and suggests that the response to glucans may not be confined to leukocytes.
真菌细胞壁葡聚糖通过与巨噬细胞、中性粒细胞和自然杀伤细胞上的膜受体相互作用,非特异性地刺激先天免疫的各个方面。我们研究了水溶性葡聚糖在正常人冠状动脉或真皮血管内皮细胞(VECs)原代培养物中的结合情况。VECs的膜表现出饱和结合。竞争研究表明VECs上存在至少两个葡聚糖结合位点。磷酸葡聚糖分别以3.7 microM的解离常数(KD)与冠状动脉VECs的所有结合位点竞争,以11 microM的解离常数与真皮VECs的所有结合位点竞争。海带多糖,一种低分子量葡聚糖,竞争47%至51%的结合(KD = 2.8 - 2.9 microM),表明存在至少两个结合位点。葡聚糖(1微克/毫升)以时间依赖性方式刺激VEC核因子κB核结合活性和白细胞介素8表达,但不刺激血管内皮生长因子的表达。这是关于人VECs上葡聚糖模式识别受体的首次报道。它还提供了首个证据,即葡聚糖可通过刺激细胞因子基因直接调节VECs的功能活性。这些结果为宿主识别和应对真菌细胞壁产物的机制提供了新见解,并表明对葡聚糖的反应可能不限于白细胞。