Fechner H, Blankenstein P, Looman A C, Elwert J, Geue L, Albrecht C, Kurg A, Beier D, Marquardt O, Ebner D
Faculty of Veterinary Medicine, Free University of Berlin, Luisenstrasse 56, Berlin D-10117, Germany.
Virology. 1997 Oct 27;237(2):261-9. doi: 10.1006/viro.1997.8784.
Infection of cattle with the bovine leukemia virus (BLV) results in a strong permanent antibody response to the BLV antigens some weeks after infection. However, cattle may carry provirus and not have detectable antibody titers. To prove the occurrence of different BLV provirus variants in German cattle and to study the influence of special BLV variants on the immunoreaction, a 444-bp fragment of the env gene of 35 naturally BLV infected animals was analyzed. Seven different groups of BLV provirus variants were found on the basis of restriction fragment length polymorphism. Three BLV provirus variant groups and five additionally sequenced BLV isolates showed a high similarity to BLV provirus isolates from other geographical areas. The variation in nucleotide sequence of the five BLV isolates compared with nine previously sequenced BLV isolates ranged up to 5. 3%. While BLV provirus variant groups A, C, D, E, F, and G were clearly related to agar-gel immunodiffusion test (AGID)- and enzyme-linked immunosorbent assay (ELISA)-positive animals, BLV provirus variant group B was solely found in permanent AGID- and ELISA-negative or in transient ELISA-positive animals. Altogether, these results indicate that special BLV provirus variants may be responsible for atypical forms of BLV infection in cattle.
牛感染牛白血病病毒（BLV）后，在感染数周后会对BLV抗原产生强烈的永久性抗体反应。然而，牛可能携带前病毒但抗体滴度检测不到。为了证明德国牛中存在不同的BLV前病毒变体，并研究特殊BLV变体对免疫反应的影响，对35头自然感染BLV的动物的env基因的444bp片段进行了分析。基于限制性片段长度多态性，发现了7个不同的BLV前病毒变体组。三个BLV前病毒变体组和另外五个测序的BLV分离株与来自其他地理区域的BLV前病毒分离株高度相似。与九个先前测序的BLV分离株相比，五个BLV分离株的核苷酸序列变异高达5.3%。虽然BLV前病毒变体组A、C、D、E、F和G与琼脂凝胶免疫扩散试验（AGID）和酶联免疫吸附试验（ELISA）阳性动物明显相关，但BLV前病毒变体组B仅在永久性AGID和ELISA阴性或短暂ELISA阳性动物中发现。总之，这些结果表明，特殊的BLV前病毒变体可能是牛中BLV非典型感染形式的原因。
