Jones P P, Craig S W, Cebra J J, Herzenberg L A
J Exp Med. 1974 Aug 1;140(2):452-69. doi: 10.1084/jem.140.2.452.
To determine whether or not B lymphocytes are committed to the synthesis of a single immunoglobulin heavy chain isotype during their differentiation into plasma cells, rabbit lymph node and Peyer's patch cells were separated into populations with and without membrane IgM, using a fluorescence-activated cell sorter (FACS). The potential of the micro-bearing (micro+) and non-micro-bearing (micro-) cells to give rise to plasma cells both in vivo after transfer into irradiated recipients and in vitro in the presence of pokeweed mitogen was assessed by immunofluorescence techniques, and the relative proportions of the cytoplasmic Ig-stained cells (CSC) synthesizing each class of heavy chains were determined. Most of the CSC arising in vitro from micro-bearing lymph node and Peyer's patch cells contained IgM; all IgM CSC appeared to be derived from micro+ cells. Peyer's patch lymphocytes, however, did not generate IgM CSC after cell transfer and thus may be functionally different from lymph node micro+ cells. It was found also that nearly all of the many IgA CSC generated by Peyer's patch lymphocytes either in culture or after transfer were derived from micro- cells. Further fractionation of these micro- cells with the FACS after they had been membrane stained with anti-b locus allotype reagents revealed that the precursors of IgA CSC belong to a minor population of cells which do have b locus light chain determinants on their membranes, although they do not have detectable micro-chains. These cells are not found in lymph nodes. Although the majority of Peyer's patch and lymph node cells were found to be precommitted to the synthesis of a single heavy chain isotype, a small proportion of cells may not be similarly restricted. Some of the CSC with membrane IgM were found to contain cytoplasmic IgA or IgG. In addition, micro+ populations did give rise to low numbers of IgA and IgG CSC. The implications of these results, obtained under experimental conditions, on the normal differentiation of B lymphocytes in situ are discussed.
为了确定B淋巴细胞在分化为浆细胞的过程中是否致力于合成单一免疫球蛋白重链同种型，使用荧光激活细胞分选仪（FACS）将兔淋巴结和派伊尔结细胞分离为带有和不带有膜IgM的细胞群体。通过免疫荧光技术评估了微载体阳性（micro+）和无微载体（micro-）细胞在转移到受辐照受体体内后以及在体外有商陆丝裂原存在的情况下产生浆细胞的潜力，并确定了合成各类重链的细胞质Ig染色细胞（CSC）的相对比例。体外从带有微载体的淋巴结和派伊尔结细胞产生的大多数CSC含有IgM；所有IgM CSC似乎都来源于micro+细胞。然而，派伊尔结淋巴细胞在细胞转移后并未产生IgM CSC，因此其功能可能与淋巴结micro+细胞不同。还发现，派伊尔结淋巴细胞在培养或转移后产生的几乎所有许多IgA CSC都来源于micro-细胞。在用抗b基因座同种异型试剂对这些micro-细胞进行膜染色后，用FACS对其进一步分级分离，结果显示IgA CSC的前体属于一小部分细胞群体，这些细胞的膜上确实有b基因座轻链决定簇，尽管它们没有可检测到的微链。这些细胞在淋巴结中未发现。虽然发现派派伊尔结和淋巴结细胞中的大多数预先致力于合成单一重链同种型，但一小部分细胞可能没有受到类似的限制。一些带有膜IgM的CSC被发现含有细胞质IgA或IgG。此外，micro+群体确实产生了少量的IgA和IgG CSC。讨论了在实验条件下获得的这些结果对B淋巴细胞在原位正常分化的影响。
