Eisenberg L, Prystowsky M B, Dick R F, Sosman J A, Fitch F W, Quintáns J
J Immunol. 1984 Mar;132(3):1305-10.
In vitro PFC responses to the thymus-independent (TI) antigen Streptococcus pneumoniae R36a require T cell replacing factor(s) (TRF). This requirement for TRF is as significant as for the thymus-dependent (TD) antigen SRBC. TRF is shown to be distinct from IL 2 by the following observations: 1) culture supernatants from the cloned T cell line L2, collected over an 8-day period after allogeneic stimulation, transiently contain IL 2 activity but maintain high levels of TRF activity throughout 192 hr; 2) L2V, a variant subclone of L2, produces much higher levels of TRF activity than the parental line but no detectable IL 2 activity; 3) the addition of IL2+, TRF- supernatants from the T cell hybridoma FS6-14.13 does not affect the L2V SF-driven PFC responses to R36a or SRBC; and 4) the addition of contaminating T cells to cultures containing T cell-depleted spleen cells, L2V SF, and antigen does not affect the PFC response. TRF does appear to be indistinguishable from polyclonal B cell stimulating factor (BCSF), which stimulates polyclonal PFC responses in the absence of antigen, mitogen, or anti-Ig. The TRF and BCSF activities of L2V SF could not be separated by ion-exchange, hydrophobic-interaction, and gel-filtration chromatography. TRF and BCSF have an apparent m.w. of approximately 40,000.
体外对胸腺非依赖性（TI）抗原肺炎链球菌R36a的PFC反应需要T细胞替代因子（TRF）。对TRF的这种需求与对胸腺依赖性（TD）抗原SRBC的需求一样显著。通过以下观察结果表明TRF与白细胞介素2不同：1）来自克隆的T细胞系L2的培养上清液，在同种异体刺激后的8天内收集，短暂含有白细胞介素2活性，但在整个192小时内保持高水平的TRF活性；2）L2V是L2的一个变异亚克隆，产生的TRF活性水平比亲代细胞系高得多，但未检测到白细胞介素2活性；3）添加来自T细胞杂交瘤FS6-14.13的白细胞介素2阳性、TRF阴性上清液不会影响L2V超滤液驱动的对R36a或SRBC的PFC反应；4）向含有去除T细胞的脾细胞、L2V超滤液和抗原的培养物中添加污染的T细胞不会影响PFC反应。TRF似乎与多克隆B细胞刺激因子（BCSF）没有区别，后者在没有抗原、有丝分裂原或抗Ig的情况下刺激多克隆PFC反应。L2V超滤液的TRF和BCSF活性不能通过离子交换、疏水相互作用和凝胶过滤色谱法分离。TRF和BCSF的表观分子量约为40,000。
