Geha R S, Mudawwar F, Schneeberger E
J Exp Med. 1977 Jun 1;145(6):1436-48. doi: 10.1084/jem.145.6.1436.
Supernates of human T cells stimulated with TT antigen contain a factor that induces mitogenesis and immunoglobulin synthesis in autologous as well as allogeneic B cells. A fraction of the IgG produced has specificity against TT. The T-cell-derived LMF-TT eluted after albumin on Sephadex G 200 and did not contain immunoglobulin heavy chain determinants. LMF-TT was active on B cells from TT immune as well as TT- nonimmune individuals but in the latter instance the IgG secreted had no specificity against TT. B cells incubated with LMF-TT in the presence of a second antigen (DT) made IgG with specifity to that antigen provided the B-cell donor was immune to that second antigen. LMF-TT-containing supernates were depleted of TT antigen by Sephadex G 200 chromatography followed by passage over anti-TT immunosorbent columns. The antigen-free supernates were able to induce mitogenesis and IgG synthesis in B cells but the IgG produced failed to exhibit specificity against TT unless the TT antigen was readded to the B-cell cultures. The optimal concentration of LMF-TT (50 percent) inducing B-cell mitogenesis was different from the optimal concentration (20 percent) causing IgG synthesis by B cells. At low LMF concentrations (less than or equal 10 percent) addition of a second antigen to which the cell donor was immune caused an increase in the degree of B-cell mitogenesis. Submitogenic concentrations of LMF-TT (less than or equal to 5 percent) were still capable of inducingimmunoglobulin synthesis in B cells At these low concentrations of LMF-TT the proportion of anti-TT IgG over total IgG increased sharply. B cells from TT immune donors were separated on TT immunosorbent columns. Cells that bound to the column were more sensitive to the mitogenic and IgG synthetic effects of LMF-TT than unfractionated B cells. Thus, LMF is a nonspecific human T-cell helper factor which behaves like a polyclonal B-cell activator. However, in the presence of specific antigen (TT) the antigen-specific B cell is preferentially triggered by LMF. The experimental design of the present study does not rule out the additional presence of an antigen-specific helper factor in the supernates of TT-stimulated human T cells.
用破伤风类毒素（TT）抗原刺激人T细胞产生的上清液中含有一种因子，该因子可诱导自体及同种异体B细胞发生有丝分裂并合成免疫球蛋白。所产生的一部分IgG具有抗TT的特异性。在Sephadex G 200上，T细胞来源的淋巴细胞有丝分裂因子 - TT（LMF - TT）在白蛋白之后洗脱，且不含免疫球蛋白重链决定簇。LMF - TT对来自TT免疫个体以及TT非免疫个体的B细胞均有活性，但在后一种情况下，所分泌的IgG对TT无特异性。在第二种抗原（白喉类毒素，DT）存在的情况下，用LMF - TT孵育B细胞，只要B细胞供体对该第二种抗原有免疫力，就会产生对该抗原有特异性的IgG。含有LMF - TT的上清液通过Sephadex G 200柱层析，然后通过抗TT免疫吸附柱去除TT抗原。无抗原的上清液能够诱导B细胞发生有丝分裂并合成IgG，但所产生的IgG对TT无特异性，除非将TT抗原重新添加到B细胞培养物中。诱导B细胞有丝分裂的LMF - TT的最佳浓度（50%）与导致B细胞合成IgG的最佳浓度（20%）不同。在低LMF浓度（小于或等于10%）时，添加细胞供体有免疫力的第二种抗原会导致B细胞有丝分裂程度增加。亚致有丝分裂浓度的LMF - TT（小于或等于5%）仍能够诱导B细胞合成免疫球蛋白。在这些低浓度的LMF - TT下，抗TT IgG在总IgG中的比例急剧增加。来自TT免疫供体的B细胞在TT免疫吸附柱上进行分离。与柱结合的细胞比未分离的B细胞对LMF - TT的有丝分裂和IgG合成作用更敏感。因此，LMF是一种非特异性的人T细胞辅助因子，其作用类似于多克隆B细胞激活剂。然而，在存在特异性抗原（TT）的情况下，抗原特异性B细胞优先被LMF触发。本研究的实验设计并不排除在TT刺激的人T细胞上清液中额外存在抗原特异性辅助因子的可能性。
