Fiore L, Greenberg H B, Mackow E R
Department of Medicine, Stanford University, California 94305.
Virology. 1991 Apr;181(2):553-63. doi: 10.1016/0042-6822(91)90888-i.
The amino-terminal trypsin cleavage fragment of VP4, called VP8, was expressed from a recombinant baculovirus in Sf-9 cells. The baculovirus-expressed VP8 protein is antigenically conserved as demonstrated by its recognition by a library of neutralizing monoclonal antibodies. In Sf-9 cell sonicates, the expressed VP8 protein is capable of agglutinating human type O erythrocytes, indicating that the functionally intact rhesus rotavirus viral hemagglutinin is contained in the 247-amino acid VP8 trypsin cleavage fragment. Amino acid similarities between VP8 and the amino-terminal 282 amino acids of the reovirus sigma 1 protein suggests that the sigma 1 hemagglutination function resides within these amino-terminal amino acids as well. When the expressed VP8 protein was used to immunize mice, a broadly cross-reactive neutralizing antibody response was obtained. Antibodies elicited to the expressed VP8 protein neutralized viruses of serotypes 1-4 and 6 but not porcine strains OSU (st5) or Gottfried (st4). The neutralizing antibody response to VP8 appeared to be more cross-reactive than the immune response to expressed VP4 or to whole RRV virion. This suggests that subunit protein immunizations may broaden the neutralizing antibody immune responses to rotaviruses and enhance protective immunity to serotypically distinct strains.
VP4的氨基末端胰蛋白酶裂解片段，称为VP8，由重组杆状病毒在Sf-9细胞中表达。杆状病毒表达的VP8蛋白具有抗原保守性，这一点通过其被一组中和单克隆抗体识别得以证明。在Sf-9细胞超声裂解物中，表达的VP8蛋白能够凝集人O型红细胞，这表明功能完整的恒河猴轮状病毒病毒血凝素包含在247个氨基酸的VP8胰蛋白酶裂解片段中。VP8与呼肠孤病毒σ1蛋白的氨基末端282个氨基酸之间的氨基酸相似性表明，σ1血凝素功能也存在于这些氨基末端氨基酸中。当用表达的VP8蛋白免疫小鼠时，获得了广泛交叉反应的中和抗体应答。针对表达的VP8蛋白产生的抗体中和了1-4型和6型病毒，但不能中和猪毒株OSU（血清型5）或Gottfried（血清型4）。对VP8的中和抗体应答似乎比针对表达的VP4或完整RRV病毒粒子的免疫应答具有更强的交叉反应性。这表明亚单位蛋白免疫可能会拓宽对轮状病毒的中和抗体免疫应答，并增强对血清型不同毒株的保护性免疫。
