Larsson E L, Iscove N N, Coutinho A
Nature. 1980 Feb 14;283(5748):664-6. doi: 10.1038/283664a0.
The molecular and cellular basis of T-lymphocyte activation remains a central question in immunology. The growth of already proliferating T cells is known to depend on T-cell growth factor (TCGF), a physiological mitogen. Noncycling T lymphocytes, however, are not sensitive to TCGF. They require a short contact with mitogenic lectins, such as concanavalin A (Con A) or leukoagglutinin to bind and respond to TCGF, and will thereafter maintain exponential growth for long periods provided that TCGF is not limiting. While the induction of TCGF reactivity results from the direct contact of Con A with resting T cells, the lectin-dependent production of TCGF is known to involve two cell types, both present in mouse spleen. One consists of I-A-negative cells, most of which are Thy-1-positive T lymphocytes, and the other consists of I-A-positive, immunoglobulin-negative, Thy-1-negative cells, most of which are macrophages. The nature of the respective contributions of the two cell types, and in particular the cellular origin of TCGF, has not yet been established. We have now established the I-A-negative population as the source of TCGF and show here that macrophages are required to supply a 20,000-molecular weight factor, chemically and functionally distinct from TCGF, which supports the production of TCGF by the I-A-negative cells.
T淋巴细胞激活的分子和细胞基础仍然是免疫学中的核心问题。已知已经处于增殖状态的T细胞的生长依赖于T细胞生长因子（TCGF），一种生理性有丝分裂原。然而，非循环T淋巴细胞对TCGF不敏感。它们需要与有丝分裂凝集素（如刀豆球蛋白A（Con A）或白细胞凝集素）短暂接触以结合并对TCGF作出反应，并且此后只要TCGF不成为限制因素，就能长期维持指数生长。虽然TCGF反应性的诱导是由Con A与静止T细胞的直接接触引起的，但已知凝集素依赖性TCGF的产生涉及两种细胞类型，二者均存在于小鼠脾脏中。一种由I-A阴性细胞组成，其中大多数是Thy-1阳性T淋巴细胞，另一种由I-A阳性、免疫球蛋白阴性、Thy-1阴性细胞组成，其中大多数是巨噬细胞。两种细胞类型各自的贡献性质，尤其是TCGF的细胞起源，尚未确定。我们现已确定I-A阴性群体是TCGF的来源，并在此表明巨噬细胞需要提供一种分子量为20,000的因子，该因子在化学和功能上与TCGF不同，它支持I-A阴性细胞产生TCGF。
