Lesley J, Schulte R, Trotter J, Hyman R
Department of Cancer Biology, Salk Institute, San Diego, California 92138.
Cell Immunol. 1988 Mar;112(1):40-54. doi: 10.1016/0008-8749(88)90274-2.
A proportion of Pgp-1+ cells in the thymus have been shown to have progenitor activity. In adult AKR/Cum mice the total Pgp-1+ population in the thymus differs from that of the bulk of thymocytes and is antigenically heterogeneous when examined by flow cytometry. Pgp-1+ thymocytes are enriched for several minor cell populations compared to total thymocytes: B2A2-, interleukin-2-receptor+ (IL-2R+), and Lyt-2-, L3T4-. However, these subsets are still a minor proportion of the Pgp-1+ cells, the majority being Lyt-2+ and/or L3T4+ and B2A2+. Pgp-1+ thymocytes also differ from the bulk of thymocytes in having lower amounts of Thy-1 and in showing a higher proportion of single positive (Lyt-2+, L3T4- or Lyt-2-, L3T4+) cells. Populations of adult thymocytes that are enriched in progenitor cells can be isolated by cytotoxic depletion using either anti-Thy-1 antibody (Thy-1 depletion) or anti-Lyt-2 and anti-L3T4 antibody (Lyt-2, L3T4 depletion). Pgp-1+ cells in progenitor cell-enriched populations are also phenotypically heterogeneous. Pgp-1+ cells in both populations may be IL-2R+ or IL-2R- and B2A2+ or B2A2-. The population of Pgp-1+ cells in progenitor cell-enriched populations in the adult differs from that of the fetus at 14 days of gestation in that in the 14-day fetus, most Pgp-1+ cells are IL-2R+. By Day 15 of gestation, distinct populations of Pgp-1+, IL-2R-; Pgp-1+, IL-2R+; and Pgp-1-, IL-2R+ cells are observed. In the 15-day fetus, as in the adult, many Pgp-1+ thymocytes express low to moderate levels of Thy-1. The total percentage of Pgp-1+ cells in the thymus varies among different mouse strains, ranging from 4 to 35% in the thymus of young adult mice. Pgp 1.1 strains contain more detectably Pgp-1+ thymocytes than Pgp 1.2 strains; however, there is variability in the proportion of Pgp-1+ cells, even among Pgp 1.2 strains. In contrast to AKR/Cum mice, the Pgp-1+ thymocyte population in BALB/c mice, which contain a high proportion of Pgp-1+ thymocytes, closely resembles the total thymocyte population.
胸腺中一定比例的Pgp-1+细胞已被证明具有祖细胞活性。在成年AKR/Cum小鼠中，胸腺中总的Pgp-1+细胞群体与大多数胸腺细胞不同，通过流式细胞术检测时其抗原性具有异质性。与总的胸腺细胞相比，Pgp-1+胸腺细胞富集了几个较小的细胞群体：B2A2-、白细胞介素-2受体+(IL-2R+)以及Lyt-2-、L3T4-。然而，这些亚群在Pgp-1+细胞中仍占较小比例，大多数为Lyt-2+和/或L3T4+以及B2A2+。Pgp-1+胸腺细胞与大多数胸腺细胞的不同之处还在于其Thy-1含量较低，并且单阳性(Lyt-2+、L3T4-或Lyt-2-、L3T4+)细胞的比例较高。通过使用抗Thy-1抗体(Thy-1去除)或抗Lyt-2和抗L3T4抗体(Lyt-2、L3T4去除)进行细胞毒性去除，可以分离出富含祖细胞的成年胸腺细胞群体。富含祖细胞群体中的Pgp-1+细胞在表型上也具有异质性。这两个群体中的Pgp-1+细胞可能是IL-2R+或IL-2R-以及B2A2+或B2A2-。成年富含祖细胞群体中的Pgp-1+细胞群体与妊娠14天时胎儿的不同，在妊娠14天的胎儿中，大多数Pgp-1+细胞是IL-2R+。到妊娠第15天时，可观察到Pgp-1+、IL-2R-；Pgp-1+、IL-2R+；以及Pgp-1-、IL-2R+细胞的不同群体。在15天的胎儿中，与成年情况一样，许多Pgp-1+胸腺细胞表达低至中等水平的Thy-1。胸腺中Pgp-1+细胞的总百分比在不同小鼠品系中有所不同，在年轻成年小鼠的胸腺中为4%至35%。Pgp 1.1品系比Pgp 1.2品系含有更多可检测到的Pgp-1+胸腺细胞；然而，即使在Pgp 1.2品系中，Pgp-1+细胞的比例也存在差异。与AKR/Cum小鼠不同，BALB/c小鼠中Pgp-1+胸腺细胞群体，其Pgp-1+胸腺细胞比例较高，但与总的胸腺细胞群体非常相似。
