Muul L M, Mond J J, Finkelman F D
Eur J Immunol. 1983 Nov;13(11):900-5. doi: 10.1002/eji.1830131108.
It has recently been demonstrated that the injection of adult mice with an affinity-purified goat antibody to mouse IgD (GaM delta) stimulates activation of the humoral immune system that resembles, on a polyclonal level, specific B cell activation by a T cell-dependent antigen. One to 2 days after adult BALB/c mice are injected with 200 micrograms of GaM delta, their splenic B lymphocytes undergo a series of T-independent activation steps that include increases in surface (s) Ia expression, cell size and DNA synthesis. Seven days after GaM delta injection, these cells undergo T-dependent activation steps, that include further proliferation as well as differentiation into IgG1-secreting cells. We have now studied the ontogeny of the T-independent (day 2) and T-dependent (day 7) activation steps by injecting 100-200 micrograms of GaM delta into 3-day- to 10-week-old BALB/c mice. GaM delta failed to induce increases in B cell sIa expression or size 2 days after injection of mice 2 weeks old or younger and failed to stimulate increased DNA synthesis 2 days after injection of 4-week-old mice. In contrast, increases in spleen cell sIa expression, size and DNA synthesis were seen 7 days after injection of 6- to 8-day-old mice. Furthermore, increases in the numbers of spleen cells with large amounts of intracytoplasmic IgG1 were seen at the same time, although these increases were much less than were seen in GaM delta-treated adult mice. Thus, the ability of GaM delta to induce T help and to act in concert with such help to stimulate B cell proliferation and differentiation precedes in ontogeny the ability of GaM delta to directly induce B cell proliferation and early differentiative events. In addition, the early activating events that we have studied are not required for T-dependent B cell proliferation and antibody production to occur, although they appear to contribute to the magnitude of clonal expansion and antibody production.
最近有研究表明，给成年小鼠注射经亲和纯化的抗小鼠IgD山羊抗体（GaMδ），可刺激体液免疫系统的激活，在多克隆水平上，这类似于T细胞依赖性抗原对特异性B细胞的激活。成年BALB/c小鼠注射200微克GaMδ后1至2天，其脾脏B淋巴细胞会经历一系列非T细胞依赖性激活步骤，包括表面（s）Ia表达增加、细胞大小增大和DNA合成增加。注射GaMδ7天后，这些细胞会经历T细胞依赖性激活步骤，包括进一步增殖以及分化为分泌IgG1的细胞。我们现在通过给3天大至10周龄的BALB/c小鼠注射100 - 200微克GaMδ，研究了非T细胞依赖性（第2天）和T细胞依赖性（第7天）激活步骤的个体发生情况。注射GaMδ2天后，2周龄及以下的小鼠B细胞sIa表达或大小未增加，4周龄小鼠注射后2天也未刺激DNA合成增加。相比之下，6至8日龄小鼠注射后7天，脾脏细胞sIa表达、大小和DNA合成增加。此外，同时观察到大量胞质内IgG1的脾脏细胞数量增加，尽管这些增加远低于GaMδ处理的成年小鼠。因此，GaMδ诱导T辅助并与这种辅助协同作用以刺激B细胞增殖和分化的能力在个体发生上先于GaMδ直接诱导B细胞增殖和早期分化事件的能力。此外，我们研究的早期激活事件并非T细胞依赖性B细胞增殖和抗体产生所必需，尽管它们似乎有助于克隆扩增和抗体产生的程度。
