Mérant Catherine, Messouak Ali, Cadoré Jean-Luc, Monier Jean-Claude
Laboratoire d'Immunopathologie, Service de Médecine, Ecole Nationale Vétérinaire de Lyon, Marcy-l'Etoile, France.
Glycoconj J. 2005 Feb;22(1-2):27-34. doi: 10.1007/s10719-005-0228-2.
In mammals, the binding of peanut agglutinin (PNA) on the plasma membrane defines subpopulations among lymphocytes from peripheral blood and lymphoid organs. PNA binds Galbeta 1,3GalNAc residues provided that they are not sialylated. Here, we studied the expression of PNA-binding glycans on healthy horse peripheral blood, thymus, lymph node and spleen lymphocytes. We first demonstrated the binding specificity of PNA for galactose residues by competition experiments and the inhibitory role of sialic acids in PNA binding by sialidase digestion. Unlike human and murine lymphocytes, all equine lymphocytes were found positive by flow cytometry analysis. Double-staining analyses showed that lymphocytes expressing high levels of PNA-binding glycans (PNA(high) lymphocytes) were made up of the great majority of CD5(+), CD4(+) and CD8(+) cells, and of 30 and 50% of sIg-bearing lymphocytes in peripheral blood and in lymph nodes or spleen, respectively. Lectin histochemistry suggested that lymph node germinal centres contained PNA(high) B cells. Contrary to what is found in humans and mice, PNA staining intensity on CD5(+), CD4(+) and CD8(+) cells did not differentiate immature from mature T lymphocytes in the equine thymus. The functional consequences of these differences are discussed.
在哺乳动物中，花生凝集素（PNA）与质膜的结合可区分外周血和淋巴器官中淋巴细胞的亚群。PNA可结合β1,3连接的N-乙酰半乳糖胺残基，前提是这些残基未被唾液酸化。在此，我们研究了健康马外周血、胸腺、淋巴结和脾脏淋巴细胞上PNA结合聚糖的表达。我们首先通过竞争实验证明了PNA对半乳糖残基的结合特异性，并通过唾液酸酶消化证明了唾液酸在PNA结合中的抑制作用。与人类和小鼠淋巴细胞不同，通过流式细胞术分析发现所有马淋巴细胞均呈阳性。双重染色分析表明，表达高水平PNA结合聚糖的淋巴细胞（PNA(高)淋巴细胞）主要由CD5(+)、CD4(+)和CD8(+)细胞组成，在外周血以及淋巴结或脾脏中分别占含表面免疫球蛋白（sIg）淋巴细胞的30%和50%。凝集素组织化学表明，淋巴结生发中心含有PNA(高) B细胞。与人类和小鼠不同的是，马胸腺中CD5(+)、CD4(+)和CD8(+)细胞上的PNA染色强度无法区分未成熟和成熟T淋巴细胞。本文讨论了这些差异的功能后果。
