Heine H G, Hyatt A D, Boyle D B
CSIRO, Australian Animal Health Laboratory, Geelong, Victoria.
Virus Res. 1994 Jun;32(3):313-28. doi: 10.1016/0168-1702(94)90080-9.
The host protective antigen gene VP2 of infectious bursal disease virus (IBDV) was genetically modified and expressed by recombinant fowlpox viruses (rFPV). To achieve cell surface localization, VP2 was expressed as a hybrid protein with signal sequence and membrane anchors of influenza virus hemagglutinin or neuraminidase. Native VP2 was expressed as VP2 alone or as self-processing VP2-VP4-VP3 polyprotein for coexpression of IBDV structural proteins. VP2 hybrid protein containing the carboxy-terminal membrane anchor sequence of influenza virus hemagglutinin was located on the cell surface and was N-glycosylated. The expression of VP2 fused to the N-terminal signal/anchor sequence of influenza virus neuraminidase led to cell lysis and the VP2 protein remained mainly unglycosylated. Cell surface localization of VP2 reduced immunogenicity (antibody induction) and abolished protection in poultry in comparison with the native VP2 expressed by FPV as VP2 alone or as the self-processing VP2-VP4-VP3. Vaccination of poultry with rFPV expressing native VP2 protein alone provided better protection from IBDV infection than VP2 derived from the VP2-VP4-VP3 polyprotein.
传染性法氏囊病病毒（IBDV）的宿主保护性抗原基因VP2通过重组禽痘病毒（rFPV）进行基因改造和表达。为实现细胞表面定位，VP2被表达为与流感病毒血凝素或神经氨酸酶的信号序列和膜锚定蛋白的融合蛋白。天然VP2单独表达为VP2或作为自我加工的VP2-VP4-VP3多蛋白表达，用于IBDV结构蛋白的共表达。含有流感病毒血凝素羧基末端膜锚定序列的VP2融合蛋白位于细胞表面并进行了N-糖基化。与FPV单独表达为VP2或作为自我加工的VP2-VP4-VP3表达的天然VP2相比，与流感病毒神经氨酸酶N末端信号/锚定序列融合的VP2的表达导致细胞裂解，并且VP2蛋白主要保持未糖基化状态。与单独由FPV表达为VP2或作为自我加工的VP2-VP4-VP3表达的天然VP2相比，VP2的细胞表面定位降低了免疫原性（抗体诱导）并消除了对家禽的保护作用。用单独表达天然VP2蛋白的rFPV对家禽进行疫苗接种比从VP2-VP4-VP3多蛋白衍生的VP2提供了更好的针对IBDV感染的保护。
