链球菌蛋白G应用于ELISA的实验研究

对酶标记链球菌蛋白Ｇ（ＳＰＧ）在ＥＬＩＳＡ的应用条件进行了研究并与ＳＰＡ作了系统比较。ＳＰＧ与ＩｇＧ结合受温度影响，３７℃结合活性高于室温和４℃；反应时间定为２ｈ反应溶液ｐＨ值升高，ＳＰＧ的结合力亦增强。在同等条件下与酶标记ＳＰＡ进行比较，结果表明ＳＰＧ对小鼠单克隆抗体、羊抗人、兔抗ＩＦＮ－γ和驴抗兔Ｉｇｇ以及牛、大鼠和人ＩｇＧ的结合力均明显高于ＳＰＡ。ＳＰＧ用于大鼠血清抗ＩＦＮ－γ抗体的检测，其阳性率和抗体滴度均大大高于ＳＰＡ。因此，ＳＰＧ作为一种广谱的、高亲和力的ＩｇＧ结合物，是应用于ＥＬＩＳＡ的理想的替代二抗。

EXPERIMENTAL ATUDY ON THE APPLICATION OF STREPTOCOCCAL PROTEIN G IN ELISA

treptococcal protein G(SPG)as a novel IgG-binding reagent was first applied in ELISA and the optimal con-ditions of temperature,incubation time and the pH value of buffer for the int eraction of SPG and lgG in ELISAwere established.The affinity of enzyme conjugated SPG and SPA to IgGs were compared under the same condi-tions. The results revealed the affinity of SPG to monoclonal IgG and polyclonal IgGs of goat,rabbit,donkey,cow, rat and human were much hlgher than that of SPA.T he positive ratio and the titers of antibody were alsoBteatly elevatedwhen SPG was used in detecting the antibody in rat sera. Therefore,SPG may be an ideal alterna-tive antibody in ELISA as a IgG conjugate with wide spectrum and high affinity.