Singh V K, Biswas S, Mathur K B, Haq W, Garg S K, Agarwal S S
Department of Immunology, Sanjay Gandhi Post-Graduate Institute of Medical Sciences, Lucknow, India.
Immunol Res. 1998;17(3):345-68. doi: 10.1007/BF02786456.
Splenopentin (SP-5, Arg-Lys-Glu-Val-Tyr) and thymopentin (TP-5, Arg-Lys-Asp-Val-Tyr) are synthetic immunomodulating peptides corresponding to the region 32-34 of a splenic product called splenin (SP) and the thymic hormone thymopoietin (TP), respectively. TP was originally isolated as a 5-kDa (49-amino acids) protein from bovine thymus while studying effects of the thymic extracts on neuromuscular transmission and was subsequently observed to affect T cell differentiation and function. TP I and II are two closely related polypeptides isolated from bovine thymus. A radioimmunoassay for TP revealed a crossreaction with a product found in spleen and lymph node. This product, named splenin, differs from TP only in position 34, aspartic acid for bovine TP and glutamic acid for bovine splenin and it was called TP III as well. Synthetic pentapeptides (TP-5) and (SP-5), reproduce the biological activities of TP and SP, respectively. It is now evident that various forms of TPs were created by proteolytic cleavage of larger proteins during isolation. cDNA clones have been isolated for three alternatively spliced mRNAs that encodes three distinct human T cell TPs. The immunomodulatory properties of TP, SP, TP-5, SP-5 and some of their synthetic analogs reported in the literature have been briefly reviewed.
脾五肽（SP - 5，精氨酸 - 赖氨酸 - 谷氨酸 - 缬氨酸 - 酪氨酸）和胸腺五肽（TP - 5，精氨酸 - 赖氨酸 - 天冬氨酸 - 缬氨酸 - 酪氨酸）是分别对应于一种名为脾素（SP）的脾脏产物的32 - 34区域和胸腺激素胸腺生成素（TP）的合成免疫调节肽。TP最初是在研究胸腺提取物对神经肌肉传递的影响时从牛胸腺中分离得到的一种5 kDa（49个氨基酸）的蛋白质，随后观察到它会影响T细胞的分化和功能。TP I和II是从牛胸腺中分离出的两种密切相关的多肽。一种针对TP的放射免疫测定显示与在脾脏和淋巴结中发现的一种产物有交叉反应。这种产物名为脾素，与TP仅在第34位不同，牛TP的第34位是天冬氨酸，牛脾素的第34位是谷氨酸，它也被称为TP III。合成五肽（TP - 5）和（SP - 5）分别重现了TP和SP的生物活性。现在很明显在分离过程中各种形式的TP是由较大蛋白质的蛋白水解切割产生的。已经分离出了编码三种不同人类T细胞TP的三种选择性剪接mRNA的cDNA克隆。本文简要综述了文献中报道的TP、SP、TP - 5、SP - 5及其一些合成类似物的免疫调节特性。
