Schwartz I, Bensaid A, Polack B, Perrin B, Berthelemy M, Levy D
URA-Institut National de la Recherche Agronomique, Immuno-Pathologie Cellulaire et Moléculaire, Ecole Nationale Vétérinaire, Maisons-Alfort, France.
J Virol. 1994 Jul;68(7):4589-96. doi: 10.1128/JVI.68.7.4589-4596.1994.
Bovine leukemia virus (BLV), an oncovirus related to human T-cell leukemia virus type I, causes a B-cell lymphoproliferative syndrome in cattle, leading to an inversion of the T-cell/B-cell ratio and, more rarely, to a B-cell lymphosarcoma. Sheep are highly sensitive to BLV experimental infection and develop B-cell pathologies similar to those in cattle in 90% of the cases. BLV tropism for B cells has been well documented, but the infection of other cell populations may also be involved in the BLV-induced lymphoproliferative syndrome. We thus looked for BLV provirus in other leukocyte populations in sheep and cattle by using PCR. We found that while B cells harbor the highest proviral load, CD8+ T cells, monocytes, and granulocytes, but not CD4+ T cells, also bear BLV provirus. As previously described, we found that persistent lymphocytosis in cows is characterized by an expansion of the CD5+ B-cell subpopulation but we did not confirm this observation in sheep in which the expanded B-cell population expressed the CD11b marker. Nevertheless, BLV could be detected both in bovine CD5+ and CD5- B cells and in sheep CD11b+ and CD11b- B cells, indicating that the restricted BLV tropism for a specific B-cell subpopulation cannot explain its expansion encountered in BLV infection. Altogether, this work shows that BLV tropism in leukocytes is wider than previously thought. These results lead the way to further studies of cellular interactions among B cells and other leukocytes that may intervene in the development of the lymphoproliferative syndrome induced by BLV infection.
牛白血病病毒（BLV）是一种与人类I型T细胞白血病病毒相关的致瘤病毒，可引起牛的B细胞淋巴增殖综合征，导致T细胞/B细胞比例倒置，更罕见的情况下会引发B细胞淋巴瘤。绵羊对BLV实验性感染高度敏感，90%的病例会出现与牛相似的B细胞病变。BLV对B细胞的嗜性已有充分记录，但其他细胞群体的感染也可能参与BLV诱导的淋巴增殖综合征。因此，我们通过PCR在绵羊和牛的其他白细胞群体中寻找BLV前病毒。我们发现，虽然B细胞携带的前病毒载量最高，但CD8 + T细胞、单核细胞和粒细胞（而非CD4 + T细胞）也携带BLV前病毒。如前所述，我们发现奶牛的持续性淋巴细胞增多症的特征是CD5 + B细胞亚群的扩增，但在绵羊中未证实这一观察结果，绵羊中扩增的B细胞群体表达CD11b标记。然而，在牛的CD5 +和CD5 - B细胞以及绵羊的CD11b +和CD11b - B细胞中均能检测到BLV，这表明BLV对特定B细胞亚群的嗜性受限无法解释其在BLV感染中出现的扩增现象。总之，这项工作表明BLV在白细胞中的嗜性比以前认为的更广。这些结果为进一步研究B细胞与其他白细胞之间可能参与BLV感染诱导的淋巴增殖综合征发展的细胞相互作用开辟了道路。
