Sánchez-Salgado J L, Pereyra M A, Vivanco-Rojas O, Sierra-Castillo C, Alpuche-Osorno J J, Zenteno E, Agundis C
Departamento de Bioquimica, Laboratorio de Inmunologia, Facultad de Medicina UNAM, 04510, Mexico; Posgrado de Ciencias del Mar y Limnologia, UNAM, 04510, Mexico.
Departamento de Bioquimica, Laboratorio de Inmunologia, Facultad de Medicina UNAM, 04510, Mexico.
Fish Shellfish Immunol. 2014 Aug;39(2):450-7. doi: 10.1016/j.fsi.2014.05.039. Epub 2014 Jun 11.
Lectins participate in the immune mechanisms of crustaceans. They have been considered as humoral receptors for pathogen-associated molecular patterns; however, some reports suggest that lectins could regulate crustacean cellular functions. In the present study, we purified and characterized a serum lectin (CqL) from the hemolymph of Cherax quadricarinatus by affinity chromatography and determined its participation in the regulation of hemocytes' oxidative burst. CqL is a 290-kDa lectin in native form, constituted by 108, 80, and 29-kDa subunits. It is mainly composed of glycine, alanine, and a minor proportion of methionine and histidine. It showed no carbohydrates in its structure. CqL is composed of several isoforms, as determined by 2D-electrophoresis, and shows no homology with any crustacean protein as determined by Lc/Ms mass spectrometry. CqL agglutinated mainly rat and rabbit erythrocytes and showed a broad specificity for monosaccharides such as galactose, glucose, and sialic acid, as well as for glycoproteins, such as porcine stomach and bovine submaxillary mucin and fetuin. It is a Mn(2+)-dependent lectin. CqL recognized 8% of crayfish granular hemocytes and increased 4.2-fold the production of hemocytes' superoxide anion in vitro assays when compared with non-treated hemocytes. This effect showed the same specificity for carbohydrates as hemagglutination; moreover, superoxide dismutase and diphenyleneiodonium chloride were effective inhibitors of CqL oxidative-activation. The CqL homoreceptor is a 120-kDa glycoprotein identified in the hemocytes lysate. Our results suggest that CqL participates actively in the regulation of the generation of superoxide anions in hemocytes using NADPH-dependent mechanisms.
凝集素参与甲壳类动物的免疫机制。它们被认为是病原体相关分子模式的体液受体；然而，一些报告表明凝集素可能调节甲壳类动物的细胞功能。在本研究中，我们通过亲和层析从四脊滑螯虾的血淋巴中纯化并鉴定了一种血清凝集素（CqL），并确定了其在血细胞氧化爆发调节中的作用。CqL是一种天然形式的290 kDa凝集素，由108 kDa、80 kDa和29 kDa的亚基组成。它主要由甘氨酸、丙氨酸以及少量的蛋氨酸和组氨酸组成。其结构中不含碳水化合物。通过二维电泳确定，CqL由几种同工型组成，通过液相色谱/质谱法确定，它与任何甲壳类动物蛋白均无同源性。CqL主要凝集大鼠和兔的红细胞，对半乳糖、葡萄糖和唾液酸等单糖以及猪胃、牛颌下粘蛋白和胎球蛋白等糖蛋白具有广泛的特异性。它是一种依赖锰离子（Mn(2+)）的凝集素。CqL识别8%的小龙虾颗粒血细胞，与未处理的血细胞相比，在体外试验中可使血细胞超氧阴离子的产生增加4.2倍。这种效应在碳水化合物方面表现出与血细胞凝集相同的特异性；此外，超氧化物歧化酶和二苯基碘鎓氯化物是CqL氧化激活的有效抑制剂。CqL同源受体是在血细胞裂解物中鉴定出的一种120 kDa糖蛋白。我们的结果表明，CqL通过依赖烟酰胺腺嘌呤二核苷酸磷酸（NADPH）的机制积极参与血细胞中超氧阴离子生成的调节。
