Erskine Ronald J, Corl Christine M, Gandy Jeffery C, Sordillo Lorraine M
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
Am J Vet Res. 2011 Aug;72(8):1059-64. doi: 10.2460/ajvr.72.8.1059.
To determine effects of infection with bovine leukosis virus (BLV) on lymphocyte proliferation and apoptosis in dairy cattle.
27 adult Holstein cows.
Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood from lactating Holstein cows seronegative for BLV (n = 9 cows), seropositive for BLV and aleukemic (aleukemic; 9), and seropositive for BLV and persistently lymphocytotic (PL; 9). Isolated PBMCs were assayed for mitogen-induced proliferation and were analyzed by means of flow cytometry. The PBMCs from a subset of each group were assayed for apoptosis, caspase-9 activity, and expression of selected genes related to apoptosis.
PL cows had significantly higher total lymphocyte counts and significantly lower proportions of T-lymphocyte populations than did BLV-negative and aleukemic cows. Both groups of BLV-infected cows had significantly higher proportions of B cells and major histocompatibility complex II-expressing cells than did BLV-negative cows. Proliferation with concanavalin A was significantly lower for PL cows, compared with proliferation for BLV-negative cows. Pokeweed mitogen-induced proliferation was significantly higher for aleukemic and PL cows than for BLV-negative cows. Gene expression of apoptosis-inhibitory proteins BCL2 and BCL2L1 was significantly higher for aleukemic cows and expression of BCL2 was significantly higher for PL cows than for BLV-negative cows.
Cattle infected with BLV had marked changes in PBMC populations accompanied by alterations in proliferation and apoptosis mechanisms. Because the relative distribution and function of lymphocyte populations are critical for immune competence, additional studies are needed to investigate the ability of BLV-infected cattle to respond to infectious challenge.
确定感染牛白血病病毒（BLV）对奶牛淋巴细胞增殖和凋亡的影响。
27头成年荷斯坦奶牛。
从泌乳期BLV血清阴性（n = 9头奶牛）、BLV血清阳性且无白血病（无白血病；9头）以及BLV血清阳性且持续淋巴细胞增多（PL；9头）的荷斯坦奶牛的全血中分离外周血单核细胞（PBMC）。对分离出的PBMC进行有丝分裂原诱导增殖检测，并通过流式细胞术进行分析。对每组的一个子集的PBMC进行凋亡、半胱天冬酶-9活性以及与凋亡相关的选定基因表达的检测。
与BLV阴性和无白血病奶牛相比，PL奶牛的总淋巴细胞计数显著更高，T淋巴细胞群体比例显著更低。两组BLV感染奶牛的B细胞和表达主要组织相容性复合体II的细胞比例均显著高于BLV阴性奶牛。与BLV阴性奶牛相比，PL奶牛用刀豆球蛋白A诱导的增殖显著更低。美洲商陆有丝分裂原诱导的白血病和PL奶牛的增殖显著高于BLV阴性奶牛。白血病奶牛凋亡抑制蛋白BCL2和BCL2L1的基因表达显著更高，PL奶牛BCL2的表达显著高于BLV阴性奶牛。
感染BLV的牛PBMC群体有明显变化，同时增殖和凋亡机制也发生改变。由于淋巴细胞群体的相对分布和功能对免疫能力至关重要，因此需要进一步研究来调查感染BLV的牛对感染性挑战的反应能力。
