Murakami K, Okada K, Ikawa Y, Aida Y
Laboratory of Gene Technology and Safety, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan.
Virology. 1994 Jul;202(1):458-65. doi: 10.1006/viro.1994.1362.
To investigate bovine leukemia virus (BLV)-induced leukemogenesis, we infected sheep with BLV and used flow-cytometric and immunohistological analysis to characterize the phenotypic alterations in lymphocytes from peripheral blood and lymph nodes taken from the animals with lymphoma at various stages. In sheep at the asymptomatic stage, depending on the extent of progression of the disease, the proportions of CD2(+)-, CD4(+)-, CD8(+)-, and gamma delta TCR(+)-T cells that coexpressed CD5 decreased, but CD5+ sIgM+ cells as well as CD5- sIgM+ cells increased for a period. The number of CD5+ B cells, however, rapidly decreased in the lymphoma stage. On the other hand, neoplastic lymphocytes appeared to be a monoclonal population derived from a single cell with surface phenotypes of sIgM+, B-cell-specific molecule B2+, major histocompatibility complex (MHC) class II+, OvCD5-, OvCD2-, OvCD4-, OvCD8-, gamma delta TCR-, which suggests that only CD5- B cells proliferate clonally when the disease proceeds to the lymphoma stage. Thus, rapid decrease of CD5+ B cells may be used as a marker of lymphoma stage. To identify the BLV provirus in the CD5- B and CD5+ B cells throughout the course of disease, each fraction of CD5- B and CD5+ B cell was sorted from the peripheral blood by flow cytometry and nested double polymerase chain reaction was performed. In BLV-infected but healthy sheep, BLV integrated both CD5- B and CD5+ B cells. In lymphoma, however, BLV provirus was detected only in CD5- B cells but not in CD5+ B cells. Therefore it appears that a disappearance of BLV-infected CD5+ cells is one of the critical events leading to CD5- B cell lymphoma in sheep. This is in contrast to the BLV-induced lymphoma in cattle which shows CD5+ phenotype.
为了研究牛白血病病毒（BLV）诱导的白血病发生机制，我们用BLV感染绵羊，并使用流式细胞术和免疫组织学分析来表征处于不同阶段淋巴瘤的动物外周血和淋巴结中淋巴细胞的表型变化。在无症状阶段的绵羊中，根据疾病进展程度，共表达CD5的CD2(+)、CD4(+)、CD8(+)和γδTCR(+)T细胞比例下降，但CD5+sIgM+细胞以及CD5-sIgM+细胞在一段时间内增加。然而，在淋巴瘤阶段，CD5+B细胞数量迅速减少。另一方面，肿瘤性淋巴细胞似乎是源自单个细胞的单克隆群体，其表面表型为sIgM+、B细胞特异性分子B2+、主要组织相容性复合体（MHC）II类+、OvCD5-、OvCD2-、OvCD4-、OvCD8-、γδTCR-，这表明当疾病发展到淋巴瘤阶段时，只有CD5-B细胞进行克隆性增殖。因此，CD5+B细胞的快速减少可能用作淋巴瘤阶段的标志物。为了在疾病全过程中鉴定CD5-B细胞和CD5+B细胞中的BLV前病毒，通过流式细胞术从外周血中分选CD5-B细胞和CD5+B细胞的每个组分，并进行巢式双重聚合酶链反应。在感染BLV但健康的绵羊中，BLV整合到CD5-B细胞和CD5+B细胞中。然而，在淋巴瘤中，仅在CD5-B细胞中检测到BLV前病毒，而在CD5+B细胞中未检测到。因此，受BLV感染的CD5+细胞的消失似乎是导致绵羊CD5-B细胞淋巴瘤的关键事件之一。这与牛中BLV诱导的淋巴瘤表现出CD5+表型形成对比。
