T lymphocytes of young and aged rats. II. Functional defects and the role of interleukin-2.
T lymphocytes of young and aged rats. II. Functional defects and the role of interleukin-2.
复制标题
年轻和老年大鼠的 T 淋巴细胞。
作者：
S. Gilman;J. Rosenberg;J. D. Feldman
老年刘易斯大鼠脾T淋巴细胞对ConA和PHA的反应与年轻刘易斯大鼠脾T淋巴细胞相比，具有减少的~ 3 H-TdR摄取。同种异体肿瘤细胞免疫后，老年大鼠脾细胞的~ 3 H-TdR掺入量和T细胞对肿瘤靶细胞的杀伤活性均显著低于青年大鼠。与年轻大鼠的脾细胞的类似培养物相比，用Con A培养老年大鼠的脾细胞导致Ia阳性T细胞从Ia阴性前体的转化减少。青年和老年大鼠的脾细胞产生大量的IL-2响应于Con A刺激。然而，“老”T细胞结合相对较少的IL-2，在培养中不利用它，并且不像“年轻”T细胞那样对具有增强的3 H-TdR摄取的外源性IL-2作出响应。在同种异体MLTC中，与“年轻”细胞相比，“老”T淋巴细胞产生很少的IL-2，并且“年轻”和“老”细胞都对外源性IL-2产生反应，具有增强的3 H-TdR摄取和增加的细胞毒活性。这些数据表明，IL-2的合成和/或识别缺陷以及Ia抗原表达调节缺陷可能是老年动物T细胞功能降低的部分原因。
Splenic T lymphocytes of aged Lewis rats respond to Con A and PHA with diminished 3H-TdR uptake compared with splenic T lymphocytes of young Lewis rats. After immunization with allogeneic tumor cells, uptake of 3H-TdR in mixed lymphocyte-tumor cultures and T cell cytotoxicity against tumor target cells are significantly lower with spleen cells of aged rats compared with those of young rats. The culture of spleen cells of aged rats with Con A results in a diminished conversion of Ia-positive T cells from Ia-negative precursors compared with similar cultures of spleen cells of young rats. Spleen cells of both young and aged rats produce high amounts of IL-2 in response to Con A stimulation. "Old" T cells, however, bind relatively little IL-2, do not utilize it in culture, and do not respond to exogenous IL-2 with enhanced 3H-TdR uptake as do "young" T cells. In allogeneic MLTC, "old" T lymphocytes produce little IL-2 compared with "young" cells, and both "young" and "old" cells respond to exogenous IL-2 with enhanced 3H-TdR uptake and increased cytotoxic activity. The data suggest defects in the synthesis and/or recognition of IL-2 as well as defects in the regulation of Ia antigen expression may be responsible, in part, for the reduced T cell function in aged animals.