Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki 305-0856, Japan.
Microbiol Immunol. 2010 Feb;54(2):112-21. doi: 10.1111/j.1348-0421.2009.00190.x.
mAbs T1 and T2 were established by immunizing PrP gene ablated mice with recombinant MoPrP of residues 121-231. Both mAbs were cross-reactive with PrP from hamster, sheep, cattle and deer. A linear epitope of mAb T1 was identified at residues 137-143 of MoPrP and buried in PrP(C) expressed on the cell surface. mAb T1 showed no inhibitory effect on accumulation of PrP(Sc) in cultured scrapie-infected neuroblastoma (ScN2a) cells. In contrast, mAb T2 recognized a discontinuous epitope ranged on, or structured by, residues 132-217 and this epitope was exposed on the cell surface PrP(C). mAb T2 showed an excellent inhibitory effect on PrP(Sc) accumulation in vitro at a 50% inhibitory concentration of 0.02 microg/ml (0.14 nM). The scFv form of mAb T2 (scFv T2) was secreted in neuroblastoma (N2a58) cell cultures by transfection through eukaryotic secretion vector. Coculturing of ScN2a cells with scFv T2-producing N2a58 cells induced a clear inhibitory effect on PrP(Sc) accumulation, suggesting that scFv T2 could potentially be an immunotherapeutic tool for prion diseases by inhibition of PrP(Sc) accumulation.
mAbs T1 和 T2 是通过用重组 MoPrP（残基 121-231）免疫 PrP 基因缺失的小鼠而建立的。这两种 mAb 均与仓鼠、绵羊、牛和鹿的 PrP 发生交叉反应。mAb T1 的线性表位位于 MoPrP 的残基 137-143 处，埋藏在细胞表面表达的 PrP(C)中。mAb T1 对培养的感染瘙痒病的神经母细胞瘤（ScN2a）细胞中 PrP(Sc)的积累没有抑制作用。相比之下，mAb T2 识别一个位于或由残基 132-217 组成的不连续表位，该表位暴露在细胞表面的 PrP(C)上。mAb T2 在体外以 50%抑制浓度 0.02 microg/ml（0.14 nM）对 PrP(Sc)的积累表现出优异的抑制作用。mAb T2 的 scFv 形式（scFv T2）通过转染真核分泌载体在神经母细胞瘤（N2a58）细胞培养物中分泌。将 ScN2a 细胞与产生 scFv T2 的 N2a58 细胞共培养诱导 PrP(Sc)积累的明显抑制作用，表明 scFv T2 可能通过抑制 PrP(Sc)积累而成为朊病毒病的潜在免疫治疗工具。
