Molecular mechanism of viral pathogenecity, cytotoxicity and establishment of persistent infection

建立了hPIV-2 Toshiba株持续感染的HeLa细胞。直至传至50代，一直可见多核巨细胞。HeLa/hPIV 2/Toshiba细胞的大部分处于稳态，但一些部分显示CPE并最终死亡。因此，认为hPIV 2持续感染细胞是载体和稳态的混合物。副粘病毒持续感染的建立过程可分为5种类型，常为稳态和携带者状态的混合。我们设计了一种定量分析持续感染建立效率的方法。属于I型的hPIV 2 CA和SV 5 T1毒株的效率较高，即0.1 ~ 0.3，属于II型的SV 5 WR的效率也较高，约为0.1，但病毒没有立即建立持续感染（稳态）的能力。IV型SV 41的效率约为0.0007，与hPIV 2 Toshiba株的效率几乎相同。在副粘病毒持续感染中常发现稳态和携带者状态的混合。进一步分析了不同SeV pi株系的建株效率。亲本重组仙台病毒（rSeV（PA））、rSeV（Ppi）和rSeV（HNpi）的效率低于检测限，而rSeV（Lpi）的效率接近1。出乎意料的是，发现rSeV（Mpi）和rSeV（Fpi）能够形成持续感染的细胞，尽管效率约为0.001，表明Fpi和Mpi蛋白都有助于SeVpi持续感染的建立效率。

HeLa cells persistently infected with hPIV-2 Toshiba strain were established. Until 50 passages, multinucleated giant cells were detected all the time. The greater part of HeLa/hPIV2/Toshiba cells are steady states, but some fractions show CPE and eventually die. Thus, hPIV2 persistently infected cells are considered to be a mixture of carrier and steady states. Establishing processes of persistent infection by paramyxoviruses were classified into 5types.A mixture of steady state and carrier state was often found in persistent infection by paramyxoviruses. We devised a quantitative method for analyzing establishing-efficiency of persistent infection. The efficiency of hPIV2 CA and SV5 T1 strains belonging to type I was high, that is, 0.1〜0.3 and the efficiency of SV5 WR belonging to type II was also high, approximately 0.1, though the virus had no ability to immediately establish persistent infection (steady state). The efficiency of SV41 belonging to type IV was about 0.0007 and was almost same as that of hPIV2 Toshiba strain. A mixture of steady state and carrier state is often found in persistent infection by paramyxoviruses. Furthermore, the establishing efficiency of various SeV pi strain was further analyzed in detail. The efficiency of parent recombinant Sendai virus (rSeV (PA) ), rSeV (Ppi) and rSeV (HNpi) was below the limit of detection, while that of rSeV (Lpi) was nearly 1. Unexpectedly, rSeV (Mpi) and rSeV (Fpi) were found to be capable of forming persistently-infected cells, although the efficiency was around 0.001, indicating that both Fpi and Mpi proteins contribute to the establishing efficiency of persistent infection of SeVpi.