Solvason N, Kearney J F
Department of Microbiology, University of Alabama, Birmingham 35294.
J Exp Med. 1992 Feb 1;175(2):397-404. doi: 10.1084/jem.175.2.397.
The fetal mouse omentum has been shown to be a source of precursors that exclusively reconstitutes Ly1+ B cells and the closely related Ly1- sister population, but not conventional B cells or T cells. We have extended these studies to compare B cell development in the human fetal omentum, liver, and spleen, and to demonstrate that the pro/pre-B cell compartment (CD24+, sIgM-) is detected in the omentum and liver but not spleen as early as 8 wk of gestation. From 8 to 12 wk of gestation, the proportions of IgM+ cells that were pre-B cells (cIgM+/sIgM-) in the omentum and liver were 53 +/- 15% and 45 +/- 13%, respectively, and IgM+ cells were not detectable in the spleen. After 12 wk, the percentage of pre-B cells was unchanged in the fetal liver (41 +/- 10%) but decreased significantly in the omentum (25 +/- 14%); pre-B cells were now detected in the spleen but at much lower percentages (2 +/- 3%) than either the omentum or liver. The nuclear enzyme, Tdt, was detected in approximately 25% of the CD24+ cells in the omentum and liver during the 8-12-wk time period, however, Tdt+ cells were not detected in the spleen. Approximately 40% of the mature B cells found in the omentum and spleen were CD5+ compared with only 20% in the liver. These results demonstrate that the fetal omentum, like the fetal liver and bone marrow, is a primary site of B cell development.
已证明胎鼠大网膜是前体细胞的来源，这些前体细胞专门重组成Ly1⁺ B细胞和密切相关的Ly1⁻姐妹群体，但不能重组成传统B细胞或T细胞。我们扩展了这些研究，以比较人类胎儿大网膜、肝脏和脾脏中的B细胞发育，并证明早在妊娠8周时，在大网膜和肝脏中可检测到前B细胞/前B细胞区室（CD24⁺，sIgM⁻），但在脾脏中未检测到。在妊娠8至12周期间，大网膜和肝脏中作为前B细胞（cIgM⁺/sIgM⁻）的IgM⁺细胞比例分别为53±15%和45±13%，在脾脏中未检测到IgM⁺细胞。12周后，胎儿肝脏中前B细胞的百分比保持不变（41±10%），但在大网膜中显著下降（25±14%）；此时在脾脏中检测到了前B细胞，但比例远低于大网膜或肝脏（2±3%）。在8至12周期间，在大网膜和肝脏中约25%的CD24⁺细胞中检测到核酶末端脱氧核苷酸转移酶（Tdt），然而，在脾脏中未检测到Tdt⁺细胞。在大网膜和脾脏中发现的成熟B细胞中约40%为CD5⁺，而在肝脏中仅为20%。这些结果表明，胎儿大网膜与胎儿肝脏和骨髓一样，是B细胞发育的主要部位。
