Birkebak T A, Palmer G H, Davis W C, Knowles D P, McElwain T F
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040.
Leukemia. 1994 Nov;8(11):1890-9.
Alterations in the circulating CD5+ B-lymphocyte population, in vitro GP51 expression, and in vivo tax/rex expression that may precede lymphomagenesis were characterized prospectively in ten experimentally BLV-infected sheep. Infection with pathogenetic BLV resulted in a significant expansion of the circulating CD5+ B-lymphocyte population in six infected sheep. Of the remaining four infected sheep that did not have persistently elevated CD5+ B-lymphocyte counts, three developed lymphoid neoplasia within 14 months post-inoculation. Neoplastic cells from two of these three sheep were CD5- B-lymphocytes, while cells from the third were CD5+ B-lymphocytes. In vitro GP51 expression was a consistent feature of circulating lymphocytes from all three sheep developing tumors, but high level tax/rex gene transcription was not detected in circulating lymphocytes prior to lymphomagenesis. Neither in vitro GP51 expression nor high level tax/rex gene transcription was associated with expansion of the CD5+ B-lymphocyte population in sheep with significantly elevated CD5+ B-lymphocyte counts. These observations indicate that BLV infection in sheep results in expansion of the circulating CD5+ B-lymphocyte population, and that this expansion is not required for the subsequent development of BLV-associated lymphoid neoplasia.
在十只实验性感染牛白血病病毒（BLV）的绵羊中，对可能先于淋巴瘤发生的循环CD5⁺ B淋巴细胞群体、体外GP51表达以及体内tax/rex表达的变化进行了前瞻性研究。致病性BLV感染导致六只感染绵羊的循环CD5⁺ B淋巴细胞群体显著扩增。在其余四只CD5⁺ B淋巴细胞计数未持续升高的感染绵羊中，三只在接种后14个月内发生了淋巴样肿瘤。这三只绵羊中有两只的肿瘤细胞是CD5⁻ B淋巴细胞，而第三只的细胞是CD5⁺ B淋巴细胞。体外GP51表达是所有三只发生肿瘤绵羊的循环淋巴细胞的一个一致特征，但在淋巴瘤发生之前，循环淋巴细胞中未检测到高水平的tax/rex基因转录。在CD5⁺ B淋巴细胞计数显著升高的绵羊中，体外GP51表达和高水平tax/rex基因转录均与CD5⁺ B淋巴细胞群体的扩增无关。这些观察结果表明，绵羊感染BLV会导致循环CD5⁺ B淋巴细胞群体扩增，并且这种扩增对于随后发生的BLV相关淋巴样肿瘤并非必需。
