Attia W Y, Badamchian M, Goldstein A L, Spangelo B L
Department of Physiology, Medical University of South Carolina, Charleston 29425.
Immunopharmacology. 1993 Sep-Oct;26(2):171-9. doi: 10.1016/0162-3109(93)90009-f.
Thymosin fraction 5 (TF5) is a partially purified preparation of bovine thymus that affects the differentiation and function of T-cells in vitro. Interleukin-6 (IL-6) is a pleiotropic cytokine that induces terminal maturation of B-cells and T-cell activation and differentiation. Although TF5 had previously been shown to stimulate the production of a number of lymphokines, its effects on IL-6 were not known. In this study we determined the effect of TF5 on IL-6 production from rat spleen cells in vitro. TF5 (100 micrograms/ml) stimulated IL-6 production from splenocytes (0.75-3.0 x 10(5) cells/well) in the presence of 0.008-0.2 micrograms/well of the T-cell mitogen concanavalin-A (con-A) by 10-20 fold during a 72 h incubation period. Dose-response studies demonstrated that 10 micrograms/ml of TF5 was the lowest concentration capable of enhancing IL-6 production. The ability of TF5 to stimulate IL-6 production in the presence of con-A could be demonstrated within 24 h of incubation; longer incubation periods (48-72 h) correlated with further enhancements of IL-6 production. Partial purification of the IL-6-inducing activity from TF5 resulted in three subfractions possessing activity in the presence of con-A (MB2, MB3, MB7) and one in the absence of con-A (MB2). The previously characterized thymosin peptides T alpha 1 and T beta 4 had no effect on IL-6 production in the absence or presence of mitogen. This study reports a new biological activity for TF5 and suggests that a novel constituent of TF5 may enhance the production of IL-6 from spleen cells.
胸腺素组分5（TF5）是一种部分纯化的牛胸腺制剂，可在体外影响T细胞的分化和功能。白细胞介素-6（IL-6）是一种多效性细胞因子，可诱导B细胞的终末成熟以及T细胞的激活和分化。尽管先前已表明TF5能刺激多种淋巴因子的产生，但其对IL-6的影响尚不清楚。在本研究中，我们测定了TF5对体外大鼠脾细胞产生IL-6的影响。在0.008 - 0.2微克/孔的T细胞丝裂原伴刀豆球蛋白A（con-A）存在的情况下，TF5（100微克/毫升）在72小时的孵育期内可刺激脾细胞（0.75 - 3.0×10⁵细胞/孔）产生IL-6的量增加10 - 20倍。剂量反应研究表明，10微克/毫升的TF5是能够增强IL-6产生的最低浓度。在con-A存在的情况下，TF5刺激IL-6产生的能力在孵育24小时内即可显现；更长的孵育时间（48 - 72小时）与IL-6产生的进一步增强相关。从TF5中部分纯化IL-6诱导活性后得到三个在con-A存在时有活性的亚组分（MB2、MB3、MB7）和一个在con-A不存在时有活性的亚组分（MB2）。先前已鉴定的胸腺素肽Tα1和Tβ4在有或无丝裂原的情况下对IL-6的产生均无影响。本研究报道了TF5的一种新的生物学活性，并表明TF5的一种新成分可能增强脾细胞产生IL-6的能力。
