Detection Of Bovine Papillomavirus And Experiment Of Cells Infection

Bovine papilloma is hyperplastic benign lesions of both cutaneous and mucosal epitheliainduced by Bovine Papillomavirus (BPV) in cattle. It is an infectious disease extensively existingin dairy herd all over the Word. Thirteen different viral genotypes have been characterized so far;they are all strictly specie-specific even if BPV1/2may also infect horses inducing fibroblastictumors. It has not been taking seriously due to it is self-limiting benign tumor. But the benignlesions may also occasionally persist, leading to a high risk of evolving into cancer, particularly inthe presence of environmental carcinogenic co-factors such as bracken fern. This study was toconfirm the genotypes present in dairy herd in China by detection and identification of BPV.Preliminary study of cell model for BPV infection NIH-3T3cells was also carried out. It wouldprovide the basis for further research on BPV pathogenic mechanism and screening of anti-BPVeffective traditional Chinese medicine.Clinical observation, histopathology and immunohistochemistry observation were applied tocarry out first-stage diagnosis of specimens. Inoculation of tumor homogenates ontochorioallantoic membranes of11–day-old chicken embryos was applied to observe the Chickenembryo growth characteristics of BPV. PCR method was used to identify the genotype and confirmthe diagnosis of BPV infection. By infecting NIH-3T3cells with BPV suspension, themorphological changes and DNA were detected. The results showed that:(1) Bovine papillomawas mainly auliflower-like shaped and nodular, grey brown or black in colour, about0.5-7cm insize, hard in texture.(2) Histopathology observation was showed exaggerated hyperkeratosis andgranular cell with vesicular. Immunohistochemistry observation was showed cytoplasm withbown-color stained, while the control specimen was not.(3) PCR amplification showed the DNAextracted from bovine papilloma specimens were caused by BPV-1and BPV-2.(4) Inoculation ofchorioallantoic membranes was with a rare mortality and characteristic changes, and did not revealthe presence of viruslike particles in death embryos.(5) The morphological changes were foundand DNA was not detected in BPV suspension infected NIH-3T3cells. In conclusion, the bovinepapillomas found in this dairy herd were caused by BPV-1and BPV-2, inoculation ofchorioallantoic membranes couldn’t isolate BPV, BPV could induce morphological transformationof NIH-3T3cells.