Kolb C, Fuchs B, Weiler E
Department of Immunology, Faculty of Biology, University of Konstanz, FRG.
Eur J Immunol. 1993 Nov;23(11):2959-66. doi: 10.1002/eji.1830231135.
Single antibody-forming cells (AFC) specific for alpha(1-3) dextran (Dex) from i.p.-immunized BALB/c mice were enumerated in soft agar cultures by blotting on antigen-precoated membranes and subsequent staining via enzyme-coupled anti-IgM antibodies. Short cultures (2 h) revealed AFC as harvested ex vivo, while in long-term cultures (4 days), in the presence of lipopolysaccharide (LPS) as B cell mitogen, cells or colonies developed by differentiation in vitro. Whereas the spleen contained most AFC ex vivo in a sharp-peak response at 4 and 5 days after i.p. injection of Dex in aqueous solution, peritoneal exudate cells (PEC) contained only very few AFC. However, the same PEC population developed Dex-specific cells or colonies after 4 days of culture. The isotype of antibodies was IgM. The frequency of these Dex-specific LPS-inducible precursor cells rose exponentially in the course of the immune response to a broad plateau and was still, 11 weeks after Dex injection, approximately 40-fold higher than in non-immunized mice. Since these cells increased in frequency after antigen injection, and since they could not be detected as AFC during 2 h ex vivo, they were regarded as memory cells. They seemed to be arrested in vivo, but could be induced to differentiation and/or proliferation in vitro. Although these cells had the functional characteristics of memory cells as defined above, they produced anti-Dex antibodies of IgM isotype. Their population might be critical for the protection of the peritoneal cavity against microbial invasion from the intestines, and it may be significant in this context that we could evoke a peritoneal memory cell response only when antigen was injected intraperitoneally, but not intravenously. In athymic BALB/c-nu/nu mice only few of these Dex-specific memory cells were found. It is possible that T cells exert a regulatory influence on this pathway of differentiation.
通过将腹腔免疫的BALB/c小鼠中针对α(1-3)葡聚糖（Dex）的单抗体形成细胞（AFC）点样于预先包被抗原的膜上，并随后通过酶联抗IgM抗体进行染色，在软琼脂培养物中对其进行计数。短期培养（2小时）显示AFC如同刚从体内收获时一样，而在长期培养（4天）中，在作为B细胞有丝分裂原的脂多糖（LPS）存在的情况下，细胞或集落通过体外分化而形成。腹腔注射Dex水溶液后4天和5天，脾脏在急剧的峰值反应中含有最多的体内AFC，而腹腔渗出细胞（PEC）仅含有极少的AFC。然而，相同的PEC群体在培养4天后形成了Dex特异性细胞或集落。抗体的同种型为IgM。这些Dex特异性LPS诱导的前体细胞的频率在免疫反应过程中呈指数上升至一个宽广的平台期，并且在注射Dex 11周后，仍比未免疫的小鼠高约40倍。由于这些细胞在抗原注射后频率增加，并且由于在体内2小时内无法将其检测为AFC，因此它们被视为记忆细胞。它们似乎在体内停滞，但可在体外被诱导分化和/或增殖。尽管这些细胞具有上述记忆细胞的功能特征，但它们产生IgM同种型的抗Dex抗体。它们的群体可能对于保护腹腔免受来自肠道的微生物入侵至关重要，在这种情况下可能具有重要意义的是，只有当抗原经腹腔注射而非静脉注射时，我们才能引发腹腔记忆细胞反应。在无胸腺的BALB/c-nu/nu小鼠中，仅发现极少的这些Dex特异性记忆细胞。T细胞有可能对这种分化途径发挥调节作用。
