Structures and Activities of Prions and Prion Proteins

2012财年的成就：我们已经在体外和体内确定了痒病菌株依赖的PrPSc与补体因子的相互作用。补体因子在中枢神经系统朊病毒感染中的作用尚不清楚。在这项研究中，我们评估了补体因子在神经2a （N2a）细胞和小鼠大脑的朊病毒感染中的株依赖性反应性。用正常小鼠血清（NMS）培养持续感染Chandler或22L痒病株的N2a细胞，用磷脂基丝氨酸结合蛋白和早期凋亡标志物Annexin V进行染色。在Chandler和22L感染的细胞中，Annexin V阳性细胞比例均增加。NMS与抗c1q、C3和/或C9抗体一起预孵生，可减少chandler感染细胞中的Annexin V阳性细胞，而只有抗C3抗体对22l感染细胞有效。免疫组化显示，C1q和C3在Chandler-和22l感染小鼠大脑中的沉积是不同的。这些结果表明，补体因子的反应性在体内和体外都存在差异。

Accomplishments for FY2012: We have identified scrapie strain-dependent interactions of PrPSc with complement factors in vitro and in vivo. Roles of complement factors in prion infection of the central nervous system remain unclear. In this study, we assessed the strain-dependent reactivity of complement factors in prion infections of Neuro2a (N2a) cells and mouse brains. N2a cells persistently infected with either Chandler or 22L scrapie strains were cultured in the presence of normal mouse serum (NMS), followed by staining with the phosphatidylserine binding protein and early apoptosis marker Annexin V. The proportion of Annexin V positive cells was increased both in Chandler- and 22L-infected cells. Preincubation of NMS with anti-C1q, C3 and/or C9 antibodies reduced Annexin V positive cells in Chandler-infected cells, while only anti-C3 antibodies were effective on 22L-infected cells. Immunohistochemistry showed that deposition of C1q and C3 was different between Chandler- and 22L-infected mouse brains. These results indicate that the reactivity of complement factors differs between prion strains both in vitro and in vivo.