Molecular mechanisms of pathogenicity of rinderpestvirus and its molecular epidemio1ogy

1.重组牛瘟疫苗免疫效果的研究（1）表达牛瘟病毒H基因的牛痘病毒的免疫持续时间攻毒试验在接种疫苗后两年内进行。结果，除少数动物外，大多数接种牛在攻击中存活，表明免疫持续时间为两年。（2）表达牛瘟病毒N基因的牛痘病毒的免疫效果由于前一年在兔中未显示该病毒的保护性免疫，因此在牛中进行了试验。通过用中等毒力水平的牛瘟攻毒，牛在攻毒中存活。然而，动物通过用高毒力牛瘟病毒攻击而出现了牛瘟的临床症状。这些结果表明，该病毒的免疫效果低于表达H基因的痘苗病毒.牛瘟病毒感染的细胞免疫由于表达H基因的牛痘病毒涉及细胞免疫，因此开发了一种使用表达H基因的自体靶细胞进行细胞毒性试验的方法。通过该方法，在接种后1周确认了细胞毒性T细胞的出现，还表明表达NP蛋白的痘苗病毒的特异性表位参与了细胞介导的免疫的发展。

1. Studies on the efficacy of recombinant rinderpest vaccine(1) Duration of immunity by vaccinia virus expressing the H gene of rinderpest virusThe immunity induced by the virus had already shown to last for one year. The challenge test was conducted two years after the vaccination. As a result, most of the cattle vaccinated survived the challenge except few animals, indicating the duration of immunity for two years(2) Immune effect of vaccinia virus expressing the N gene of rinderpest virusAs the protective immunity by the virus was not shown in rabbits in the previous year, test was conducted on cattle. By the challenge with rinderpest of moderate level of virulence the cattle survived the challenge. However, the animals developed c1inical signs of rinderpest by the challenge with highly virulent rinderpest virus. These results indicate that the immunizing effect of the virus is lower than that by the vaccinia virus expressing the H gene.2. Cell-mediated immunity in rinderpest virus infectionAs the involvement of cell-mediated immunity was suggested for the vaccinia virus expressing the H gene, a method for cytotoxic test was developed by using the autologous target cells expressing the H gene. By this method appearance of cytotoxic T cells was confirmed at 1 week after the vaccination.An involvement of specific epitope in the development of cell-mediated immunity was also indicated for the vaccinia virus expressing the NP protein.