DEVELOPING AN IN VITRO MODEL OF INFECTION OF BOVINE B CELLS WITH BLV

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。牛白血病病毒（BLV）是一种感染牛的逆转录病毒。它与人类T细胞白血病病毒密切相关。然而，BLV主要感染B细胞，而不是T细胞。BLV在约5%的受感染动物中引起B细胞淋巴肉瘤，但也可在更大比例的受感染牛中引起持续的淋巴细胞增多症和其他健康问题。在之前的出版物中，Isaacson等人报道，实验感染BLV的牛对各种非BLV抗原的抗体反应增加，并且发现这些动物中表达MHC-II分子的B细胞数量显著增加。迄今为止，BLV阴性牛淋巴肉瘤（bl3）细胞与BLV感染的FLK-BLV细胞的无细胞上清液孵育已导致BLV pcr阳性的bl3细胞。这些结果目前正在得到证实，并且正在研究在FLK-BLV上清液中定量BLV的各种方法。到目前为止，通过逆转录酶试验以及使用BLV易感CC81细胞的TCID50试验来测定BLV滴度的尝试都没有成功，但仍在继续努力。此外，BLV感染的BL-3细胞将很快通过流式细胞术进行检测，以确定体外BLV感染后MHC-II表达水平是否升高。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Bovine leukemia virus (BLV) is a retrovirus that infects cattle. It is closely related to the human T cell leukemia virus. However, BLV mainly infects B cells, rather than T cells. BLV causes a B cell lymphosarcoma in about 5% of infected animals, but can also cause persistent lymphocytosis and other health problems in a larger percentage of infected cattle. In previous publications, Isaacson et al. reported that cattle experimentally infected with BLV had increased antibody responses to various non-BLV antigens, and a significantly increased number of B cells from these animals were found to express MHC-II molecules. To date, incubation of BLV-negative bovine lymphosarcoma (BL-3) cells with cell-free supernatants from BLV-infected FLK-BLV cells has resulted in the BL-3 cells becoming PCR-positive for BLV. These results are currently being confirmed, and various methods for quantitation of BLV in FLK-BLV supernatants are being investigated. Thus far, attempts to determine BLV titers by a reverse transcriptase assay, as well as by a TCID50 assay using BLV-susceptible CC81 cells, have been unsuccessful, but efforts are continuing. In addition, the BLV-infected BL-3 cells will soon be assayed by flow cytometry to determine whether levels of MHC-II expression are increased following in vitro BLV infection.