USDA, Agriculture Research Service, Avian Disease and Oncology Laboratory, East Lansing, MI 48823, USA; Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA.
USDA, Agriculture Research Service, Avian Disease and Oncology Laboratory, East Lansing, MI 48823, USA; Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA; South China Agricultural University, Guangzhou 510642, China.
Vaccine. 2014 Apr 1;32(16):1820-7. doi: 10.1016/j.vaccine.2014.01.092. Epub 2014 Feb 13.
Marek's disease (MD) remains a continual threat to the poultry industry worldwide as the MD virus continues evolving in virulence. MD has been controlled primarily by intensive use of vaccines since 1969. Based on the antigenic and pathogenic differences of the viruses that the vaccines were derived from, commercially available MD vaccines are classified into three categories, MDV-1, -2, and -3 vaccines. This study was designed to compare the protective efficacy of MDV-1 (CVI988/Rispens) and MDV-3 (HVT) vaccines against challenge of a very virulent plus strain of Marek's disease virus (vv+MDV) in experimental and commercial egg-layer lines of chickens under controlled experimental conditions. The two experimental lines (63 and 72) of chickens carry a uniform MHC B2 haplotype and are known to differ in resistance to MD. One of the two commercial egg-layer lines (WL and BL) segregates for three MHC haplotypes (B2, B15, and B21); the other is unclear. MD incidences of the unvaccinated groups of both experimental lines and both commercial lines were 100% or close to 100% induced by the vv+MDV, 648A. Survived day patterns of the unvaccinated groups significantly differed between the two experimental lines, but did not between the two commercial lines, which suggested the two experimental lines do differ in resistance to MD but not between the two commercial lines. At manufacturers' recommended vaccine dosage, two HVTs conveyed comparable protection for the MD resistant line 63 chickens as did both CVI988/Rispens used in this study. The two HVTs also conveyed comparable protection for both commercial lines of chickens as did one of two CVI988/Rispens (CVI988/Rispens-A). At a 2000PFU uniform dose, HVT and CVI988/Rispens again conveyed comparable protection for the MD resistant experimental line of chickens. The findings suggest vaccine protective efficacy is modulated by factors including the types and the sources of vaccines and the genetic backgrounds of chickens. The findings also suggest HVT delivers equal protection in MD resistant lines of chickens as does the industry-recognized golden standard of MD vaccine, CVI988/Rispens.
马立克氏病（MD）仍然是全球家禽业的持续威胁，因为 MD 病毒在毒力方面继续进化。自 1969 年以来，MD 主要通过密集使用疫苗来控制。基于疫苗来源病毒的抗原和致病性差异，市售 MD 疫苗分为三类，MDV-1、-2 和 -3 疫苗。本研究旨在比较 MDV-1（CVI988/Rispens）和 MDV-3（HVT）疫苗对实验和商业蛋鸡系鸡在受控实验条件下对非常毒力加毒株马立克氏病病毒（vv+MDV）的挑战的保护效力。这两个实验鸡系（63 和 72）携带均匀的 MHC B2 单倍型，已知对 MD 的抵抗力不同。这两个商业蛋鸡系（WL 和 BL）中的一个系分离出三种 MHC 单倍型（B2、B15 和 B21）；另一个则不清楚。未接种疫苗的两组实验鸡系和两组商业鸡系的 MD 发病率均为 100%或接近 100%，由 vv+MDV，648A 诱导。未接种疫苗的两组鸡系的存活天数模式明显不同，但两组商业鸡系之间没有差异，这表明两组实验鸡系在 MD 抵抗力上存在差异，但两组商业鸡系之间没有差异。在制造商推荐的疫苗剂量下，两种 HVT 对 MD 抗性系 63 鸡的保护作用相当，本研究中使用的两种 CVI988/Rispens 也相当。两种 HVT 对两种商业鸡系的保护作用也与两种 CVI988/Rispens 中的一种（CVI988/Rispens-A）相当。在 2000PFU 均匀剂量下，HVT 和 CVI988/Rispens 再次对 MD 抗性实验鸡系提供了相当的保护作用。这些发现表明，疫苗的保护效力受多种因素的调节，包括疫苗的类型和来源以及鸡的遗传背景。这些发现还表明，HVT 在 MD 抗性鸡系中的保护作用与业界公认的 MD 疫苗金标准 CVI988/Rispens 相当。
