Denis K A, Dorshkind K, Witte O N
J Exp Med. 1987 Aug 1;166(2):391-403. doi: 10.1084/jem.166.2.391.
Lymphoid fetal liver cultures (LFLC) are long-term, nontransformed cultures of early B lymphoid lineage cells which appear developmentally blocked at the pre-B stage in vitro. When injected into severe combined immunodeficient (SCID) mice, cells from LFLC could reconstitute splenic B lymphocytes and serum IgM. T lymphocyte reconstitution was not observed and serum IgG levels were very low. IgG3 was the predominant gamma subisotype in the serum of the LFLC-reconstituted mice, indicating impaired class switching in these B lymphocytes. When thymocytes were coinjected with LFLC, the B lymphocytes were able to class switch fully and respond to T-dependent antigens. These serological responses were heterogeneous. This experimental system allows separation of three B lymphocyte developmental stages: early differentiation in vitro, progression to IgM secretion in vivo, and late differentiation dependent upon mature T lymphocytes in vivo. The unique advantage of this system is the ability to regulate the B lymphocyte developmental pathway in a defined, stepwise manner.
淋巴样胎儿肝脏培养物（LFLC）是早期B淋巴细胞系细胞的长期非转化培养物，这些细胞在体外似乎在pre - B阶段发育受阻。当将LFLC中的细胞注射到严重联合免疫缺陷（SCID）小鼠中时，它们能够重建脾脏B淋巴细胞和血清IgM。未观察到T淋巴细胞重建，且血清IgG水平非常低。IgG3是LFLC重建小鼠血清中主要的γ亚型，表明这些B淋巴细胞中的类别转换受损。当胸腺细胞与LFLC共同注射时，B淋巴细胞能够完全进行类别转换并对T细胞依赖性抗原作出反应。这些血清学反应是异质性的。该实验系统允许分离三个B淋巴细胞发育阶段：体外早期分化、体内进展至IgM分泌以及体内依赖成熟T淋巴细胞的晚期分化。该系统的独特优势在于能够以明确、逐步的方式调节B淋巴细胞发育途径。
