人类病毒微生态学与长驻病毒群

Permanent resident virus in human being and microecology

从生命起源分析,病毒与细胞是相容的,对细胞的绝对依赖性引导了病毒的形成、发展、分布与演化,病毒存在必定有其生存、传播并延续的长期宿主。与自然界的其他物种相同,人类也伴有一群以人为长期宿主,并与人共存的病毒,这群病毒称人类长驻病毒群。免疫系统具有对抗微生物入侵的功能,病毒与具备完善免疫系统的长期宿主存在一种特殊的共存机制。因免疫系统无进入细胞识别并清除病毒核酸的功能,入侵病毒可在细胞内残留,利用残留病毒复制与免疫清除压力达成动态平衡而隐性存在。这是病毒与其长期宿主作为利益相关者和谐共处的常态,也是在物种的免疫系统发生后自然界病毒存在的常态,构成宿主的病毒微生态学。常态病毒可发生抗原变异,突破免疫压力而成为非常态,病毒可再次增殖扩散造成宿主群体的感染,待宿主建立新的群体免疫保护而回归常态。常态病毒的初次感染和非常态病毒的再次感染、可因激发免疫反应导致的免疫毒性而致病。人类长驻病毒群的确认与鉴定,对研究人类病毒性疾病与疫情的病源及流行规律、致病机制、临床表现与转归,以及防治有重大的指导意义。疫苗可成功预防常态病毒初次感染,而对于非常态病毒的再次感染,因既往疫苗与新抗原匹配的问题,理论上无效故难以评估疫苗的预防作用。

Viruses have been compatible with cells since the origin of life.The absolute dependence on cells leads to formation,development,distribution and evolution of viruses;the existence of viruses must have their long-term host for survival,spreading and extending.Like other species in nature,a group of viruses coexist with humans,which are called permanent resident virus in human being.The immune system of species has the function of anti-microbial invasion.The virus has a special coexistence mechanism with the long-term host.Because the immune system has no function to enter cells to recognize and remove viral nucleic acids,then invading viruses can be residual in cells,and as a recessive existence under the dynamic balance between residual viral replication and immune clearance pressure.This is the normal state of the virus with its long-term host coexisting harmoniously as stakeholders,and it also has been the normal state of all natural viruses after the immune system developed in host species,constituting the viral microecology of the host.The normal state viruses can undergo antigenic mutation to break through immune pressure and become abnormal,then viruses can proliferate again and spread to cause infection in host population,and would returned into normal state after a new immune protection to be established again.The primary infection of the normal state virus and the re-infection of the abnormal state virus can cause disease due to the immune toxicity induced by the immune response.The identification of permanent resident virus in human beings is of significant importance for studying the epidemiology,pathogenesis,clinical manifestations and outcomes of human viral diseases and epidemics,as well as prevention and treatment.Vaccine can successfully prevent the diseases caused by initial infection of normal state viruses.However,for the re-infection of abnormal state viruses,it is difficult to evaluate the preventive effect of vaccines because of the matching problem between previous vaccines and new antigens of abnormal state virus.