Secretory immunoglobulin a from health y human mothers' milk catalyzes nucleic acid hydrolysis

The human milk secretory immune system is known to be the first line of protection for the newborn infant against various pathogens. Secretory IgA (sIgA), the typical immunoglobulin found in secretions, can fight infections through many mechanisms. Using different methods, we have shown that sIgA from the milk of healthy women possesses DNAse and RNAse activities. The catalytic center is localized in the light chain of catalytic sIgA, while the DNA-binding center is predominantly formed by its heavy chain. The enzymic properties and substrate specificity of catalytic sIgA distinguish it from other known DNases and RNases. It is reasonable to assume, that the milk DNA- and RNA-hydrolyzing antibodies are capable not only of neutralizing viral and bacterial nucleic acids by binding these antigens as well as by hydrolyzing them. The DNA-hydrolyzing activity of Abs raises the possibility that these catalytic Abs may provide protective functions for the newborn through the hydrolysis of viral and bacterial nucleic acids.     

ELISA方法检测尿液sIgA的方法学评价

目的 为尿液sIgA测定提供ELISA方法。方法 采用ELISA方法测定尿sIgA，并进行方法学评价。结果 ELISA方法测定尿液sIgA准确性高、特异性强。敏感性达到RIA水平。结论 ELISA方法测定尿液sIgA具有临床实用价值。     

尿液sIgA ELISA测定方法的建立

目的建立尿液sIgA的ELISA测定方法.方法以对照法和棋盘滴定法确定ELISA方法测定尿液sIgA的最适实验条件.结果羊抗人分泌型IgA(SaHsIgA)包被物质量浓度为0.625mg/L,羊抗人IgA(a链)过氧化物酶(SaHIgA-HRP)最适质量浓度是1:6000,尿标本反应时间为2h,SaHIgA-HRP温育时间为1h.结论最适条件的确立为sIgA ELISA方法提供了可靠参数.