摘要
TheaimofthisstudywastoexplorethemolecularbasisfortheattenuationoftheJapaneseencephalitisvirus(JEV)vaccinestrainSA14-14-2.ThevirulenceofSA14wildJapaneseencephalitisvirus(JEV)anditsseveralattenuatedviruseswastestedbyintracerebral(i.c.)orintraperitonial(i.p.)inoculationof10-12gmice.Thestabilityofneuroattenuationwastestedbyonepassageinsucklingmousebrain.TheEproteingenesofthoseviruseswereamplifiedbyPCR,sequencedandcompared.Threeattenuatedvirusstrains,SA14-14-2vaccinevirus,SA14-9-7andSA14-5-3,didnotexhibitlethalinfectionsbyi.c.ori.p.inoculationof10-12gmiceandreverttothevirulence.Theothervirusstrain,SA14-12-1-7,showednoneuroinvasivenessbyi.p.inoculationbutresidualneurovirulencebyi.c.inoculationandrevertedtohighvirulenceafteronebrainpassage.ComparisonoftheEproteingenesequencesofthefivevirusstrainsindicatedthatthereweredifferencesoftwelvenucleotidesandeightaminoacidsbetweentheparentstrainSA14andvaccinestrainSA14-14-2,ofwhichsixaminoacids(E-107,E-176,E-439,E-138,E-279,E-315)exhibitedchangescommontothoseofSA14-9-7andSA14-5-3,threesubstitutionscommontoSA14-12-1-7.TwoaminoacidsubstitutionsatthesitesE177(T→A)andE264(Q→H)areuniquetotheSA14-14-2vaccinevirus.TheresultssuggestthatthemutationsofE-107(Leu→Phe),E-176(He→Val),andE-439(Lys→Arg)maycontributefortheattenuationofneuroinvasivenessandpartiallyfortheattenuationofneurovirulence,themutationsofE-138,E-279,E-315maynotonlycriticaltotheneuroattenuationbutalsotoitsstability.
出版日期
2006年04月14日（中国期刊网平台首次上网日期，不代表论文的发表时间）
