Forrester L M, Ansell J D, Micklem H S
J Exp Med. 1987 Apr 1;165(4):949-58. doi: 10.1084/jem.165.4.949.
CBA/N mice were crossed with CBA/Ca-Pgk-1a to produce female F1 hybrids that were heterozygous for both xid and the phosphoglycerate kinase 1 (PGK-1) allozymes. PGK acted as a quantifiable marker for the frequency of cells in which the xid-bearing X chromosome was active in lymphocytic and other cell populations. In adults, such cells (termed xid cells) were virtually absent in FACS-sorted splenic and lymph node B cells, and in all three splenic subpopulations distinguished on the basis of their relative expression of membrane mu and delta chains. Thus, the xid mutation appeared to compromise the development of all B cells. Erythrocytes, thymocytes, T cells, and granulocytes were unaffected. Selection against xid cells was less pronounced in the spleens of 2-6-wk-old mice. In the bone marrow, there was evidence for selection against xid in the production of B cells (except at 2 wk of age), but not at the pre-B cell level. These data suggest that, in competition with normal non-xid cells, newly-formed xid B cells were less likely to be incorporated into the peripheral B cell pool.
将CBA/N小鼠与CBA/Ca-Pgk-1a小鼠杂交,以产生雌性F1杂种,这些杂种对于xid和磷酸甘油酸激酶1(PGK-1)同工酶均为杂合子。PGK作为一种可量化的标记物,用于确定在淋巴细胞和其他细胞群体中携带xid的X染色体处于活跃状态的细胞频率。在成年小鼠中,在经荧光激活细胞分选术(FACS)分选的脾和淋巴结B细胞中,以及在根据膜表面μ链和δ链的相对表达区分的所有三个脾亚群中,几乎不存在此类细胞(称为xid细胞)。因此,xid突变似乎损害了所有B细胞的发育。红细胞、胸腺细胞、T细胞和粒细胞未受影响。在2至6周龄小鼠的脾脏中,针对xid细胞的选择作用不太明显。在骨髓中,有证据表明在B细胞产生过程中存在针对xid的选择作用(2周龄时除外),但在前B细胞水平不存在这种选择作用。这些数据表明,在与正常非xid细胞的竞争中,新形成的xid B细胞不太可能被纳入外周B细胞库。