乙型肝炎病毒S基因变异与乙肝疫苗免疫后HBV感染的关系

应用ＥＬＩＳＡ和ＰＣＲ方法检测１５例乙型肝炎疫苗有效免疫后乙型肝炎病毒（ＨＢＶ）感染者血中ＨＢＶ标志物和ＨＢＶ－ＤＮＡ。结果１５例被检者血ＨＢｓＡｂ均为阳性（１００％），而且均发现血中有ＨＢｓＡｂ以外的ＨＢＶ标志物阳性，所以被定为ＨＢＶ感染，ＨＢＶ－ＤＮＡ阳性９例（６０％），提示存在着ＨＢｓＡｂ阳性的ＨＢＶ感染，其原因为这些病毒可能是一种变异的病毒，其核苷酸序列不同于一般的ＨＢＶ。ＨＢＶＳ基因变异第５８７ｎｔ由Ｇ→Ａ导致ＨＢｓＡｇ中具有高度抗原性的ａ抗原决定簇的氨基酸由甘氨酸变为精氨酸，与疫苗诱导免疫有关的抗原决定簇ａ部分缺失，抗体与变异株ＨＢＶ的ＨＢｓＡｇ结合力下降，从而导致ＨＢＶ疫苗免疫失败

A study of relationship between mutation in the s region of genome and postvaccination infection with hepatitis B virus

ELISA and polymerase chain reaction (PCR) techniques were used to detect the serologic hepatitis B virus markers and HBV-DNA in 15 patients with hepatitis B,all of whom considered to have responded well to HBV vaccine.It was found that the positive rate of HBsAb was 100% and HBV infection was confirmed by the presence of additional markers of viral replication.the positive rate of HBV-DNA was 60%.The results indicate that it is possible to be infected by HBV despite presence of adequate anti-HBs level in blood.The reason is that the virus from these patients might be an escape mutant with a different sequence from that of the isolate from other patients.A point mutation from guanosine to adenosine at nucleotide position 587 resulted in an aminoacid substitution from glycine to arginine in the highly antigenic a determinant of HBsAb.In these patients,the determinant to which a large part of the vaccine-induced immunity is directed,has been partly lost,binding to HBsAb of antibody was reduced,therefore the vaccinees of HBV was failed.