Studies on age-dependent resistance of mice to hemagglutinating encephalomyelitis virus infection

研究了小鼠对致死性血凝性脑脊髓炎病毒（HEV）感染的年龄依赖性抗性。乙型肝炎病毒MB-67N株可引起中枢神经系统急性致死性感染。该病毒具有嗜神经性，可在大脑皮层神经细胞和小脑浦肯野细胞等中枢神经系统中繁殖。在鼻内感染中，提示病毒从病毒复制的原发部位通过工厂神经传播到中枢神经系统。虽然这些感染过程在成人和新生儿之间没有差异，但发现致命性脑脊髓炎的年龄依赖性抗性。随着年龄的增长，新生小鼠的耐药性逐渐增强，且脑内感染的年龄依赖性比感染的年龄依赖性更明显。成年小鼠的抗性受到小鼠遗传背景的影响，但免疫缺陷（T-、B-和nk -缺陷）和免疫抑制（强的松龙和环磷酰胺处理）小鼠的抗性没有降低。提示小鼠对HEV致死性感染的年龄依赖性抵抗与病毒从外周部位向中枢传播过程中免疫功能的成熟程度关系不大，而受病毒在中枢神经系统中对神经细胞的复制影响。引起年龄依赖性耐药的因素可能是中枢神经系统干扰素的产生或大脑皮层神经细胞的分化和成熟。

The age-dependent resistance of mice to fatal infection with hemagglutinating encephalomyelitis virus (HEV) was investigated. MB-67N strain of HEV caused acute fatal infection of central nervous system(CNS). This virus had neurotropism, and propagated in CNS such as nerve cells of cerebral cortex and Purkinje's cells in cerebellum. In intranasal(in) infection, it was suggested that the virus spread from primary sites of viral replication via offactory nerve to the CNS. Although there was no difference between these infectious process of adult and newborn, age-dependent resistance to fatal encephalomyelitis was found. The resistance of newborn mice was increased progressively accompanied with age, and of age-dependency was more remarkable in intracerebral(ic) than in infection. The resistance in adult mice was influenced with genetic background of mice, but not reduced in immunodeficient (T-, B-, and NK-deficient) and immunosuppressive (prednisolone- and cyclophosphamide-treated)mice. It was suggested that the age-dependent resistance of mice to fatal HEV infection had little relation with maturation of immunological function in viral spread from peripheral site to CNS, but influenced with viral replication on nerve cells in CNS. The factors rented with age-dependent resistance may be production of the interferon in CNS or differentiation and maturation of nerve cells in cerebral cortex.