Geerligs Harm, Spijkers Ine, Rodenberg Jeff
Pfizer Animal Health, VMRD, Hoge Wei 10, 1930 Zaventem, Belgium.
Avian Dis. 2013 Jun;57(2 Suppl):448-53. doi: 10.1637/10344-090312-Reg.1.
The Marek's disease virus (MDV) vaccine strain CVI 988 usually is grown in primary chicken embryo fibroblasts (CEFs). We found that the strains could be grown also in the QT35 and JBJ-1 cell lines to titers in the same range as in the CEFs. Both cell lines are fibroblast-like cell lines, which can be grown in flat-bottomed tissue-culture flasks, roller bottles, and on microcarriers. For growth in QT35 cells it was necessary to adapt the virus to the cell line; for growth in JBJ-1 cells this was not necessary. We investigated the efficacy of experimental CVI 988 vaccines grown in QT35 cells and JBJ-1 cells. The efficacy studies were performed in accordance with European Pharmacopoeia (EP) monograph for live MDV disease vaccines. Groups of 1-day-old specific-pathogen-free chicks were vaccinated. Nonvaccinated control groups were included in the studies. Five to 7 days after vaccination all chickens were challenged with the very virulent MDV strain RB1B. After challenge the chickens were observed for a period of 70 days for signs of MD. The protection induced by CVI 988 grown in QT35 cells as well as JBJ-1 cells complied with the requirements of the EP that prescribe that the protection index should be at least 80%. The safety of the vaccines grown in QT35 cells and JBJ-1 cells was tested in a field study in commercial layer chickens. The vaccine virus was not safe after passaging in QT35 cells. This can be explained by the presence of fragments of the genome of MDV strains in the QT35 cell line. No signs of MD were noticed in the study in which CVI988 grown in JBJ-1 cells was tested. It is concluded that the JBJ-1 cell line is a suitable substrate for the current vaccines against MD.
马立克氏病病毒（MDV）疫苗株CVI 988通常在原代鸡胚成纤维细胞（CEF）中培养。我们发现该毒株也能在QT35和JBJ - 1细胞系中生长，其滴度与在CEF中的滴度处于同一范围。这两种细胞系都是成纤维细胞样细胞系，可在平底组织培养瓶、滚瓶以及微载体上生长。对于在QT35细胞中生长，有必要使病毒适应该细胞系；而在JBJ - 1细胞中生长则无需如此。我们研究了在QT35细胞和JBJ - 1细胞中培养的实验性CVI 988疫苗的效力。效力研究是按照欧洲药典（EP）关于MDV活疫苗的专论进行的。对1日龄无特定病原体雏鸡分组进行接种。研究中包括未接种的对照组。接种后5至7天，所有鸡用超强毒MDV毒株RB1B进行攻毒。攻毒后观察鸡70天，观察马立克氏病的症状。在QT35细胞和JBJ - 1细胞中培养的CVI 988诱导的保护作用符合欧洲药典规定的保护指数应至少为80%的要求。在商品蛋鸡的田间试验中测试了在QT35细胞和JBJ - 1细胞中培养的疫苗的安全性。在QT35细胞中传代后的疫苗病毒不安全。这可以用QT35细胞系中存在MDV毒株基因组片段来解释。在测试在JBJ - 1细胞中培养的CVI988的研究中未发现马立克氏病的症状。结论是JBJ - 1细胞系是当前抗马立克氏病疫苗的合适底物。
