Im trying to produce mouse(BalB/C) mAb against to E.coli . Cellular fluids are collected, this mAb's isotype is IgG3 but can't extracted. Would you share some info with me? Previously, i used Protein G immunoaffinity column with binding buffer ( 20 mM sodium phosphate buffer pH 8 and 7), and elution buffer (100 mM glycine pH 2,7) but antibodies couldn't be binded to column. Binding fractions have high signals but elution fractions are very low. According to literature, IgG3 has higher affinity to Protein G IAC than Protein A. Im lost ! :-(