足月新生儿母源性抗-HBs及其亚型的特性

目的 分析了解足月新生儿母源性乙型肝炎表面抗体(抗-HBs)及其亚型的特性.方法 2006年12月至2007年02月在南京大学附属鼓楼医院住院分娩的单胎足月孕妇及其新生儿为研究对象,AxSYM全自动免疫分析仪定量检测63例抗-HBs阳性的单胎足月孕妇及其新生儿脐血婴儿和1月龄时的血清抗-HBs浓度,用固相酶联免疫法检测孕妇和脐血中抗-HBs 4种IgG亚型的含量,及其中和乙型肝炎患者血清中HBsAg的能力.结果 63例抗-HBs阳性孕妇分娩的新生儿脐血抗-HBs均为阳性,几何平均浓度为195.4 mIU/ml,明显高于孕妇平均水平141.6 mIU/ml(P<0.01).脐血抗-HBs浓度与母体水平高度相关(rs=0.976,P<0.01).无论是接种还是自然感染获得的抗-HBs,其4种IgG亚型均可通过胎盘,均以IgGl为主.1月龄婴儿抗-HBs平均浓度是脐血的64%,推测被动获得的抗-HBs衰减半衰期约41 d.脐血抗-HBs可中和乙型肝炎患者血清中HBsAg,其中和作用与抗-HBs浓度有关.结论 IgG型抗-HBs及其四种亚型均可通过胎盘,以IgG1为主.母源性抗-HBs可保护新生儿免受HBV感染.

Transplacentally acquired antibodies against hepatitis B surface antigen in full term infants

Objective To analyze the correlation of the concentration of antibodies against hepatitis B surface antigen (anti-HBs) between normal full term pregnant women and their newborns.Methods Sixty-three paired serum samples from infants and their anti-HBs positive mothers,who delivered in the Affiliated Drum Tower Hospital of Nanjing Medical University School from Dec.2006 to Feb.2007,were quantitatively tested for anti-HBs by AxSYM AUSAB immunoassay.Subclasses of anti-HBs IgG were analyzed.The neutralizing activity of maternal anti-HBs in infants was assessed by surrogate assay. Results All infants born to anti-HBs positive mothers were also seropositive.Anti-HBs 1evels in infants were correlated with the maternal concentration(rs=0.976,P<0.01),and majority of the infants had higher concentrations than their mothers(195.4 mIU/ml vs 141.6 mIU/ml,P<0.01).The mean half-life of maternal anti-HBs in infants was estimated to be 41 days.Anti-HBs IgGl subclass was predominantly in infants,which was in agreement with that in their mothers.Transplacentally transferred anti-HBs in infants efficiently bound the hepatitis B surface antigen derived from hepatitis B patients. Conclusions Anti-HBs IgG carl efficiently transfer through the placenta.Infants born to anti-HBs positive mothers may be immune to hepatitis B virus in the early life of several months.