The occurrence of mouse-type oligosaccharides in mouse-human chimeric immunoglobulin G

The asparagine-linked sugar chains of mouse-human chimeric IgG which is composed of the variable regions derived from mouse and the constant regions derived from human and produced in mouse cells were quantitatively released as tritium-labelled oligosaccharides by hydrazinolysis followed by N-acetylation and NaB³H₄-reduction. Paper electrophoresis in combination with sialidase digestion indicated that more than 70% of the oligosaccharides were neutral and the rest was sialylated oligosaccharides. Their structures were determined by sequential exoglycosidase digestions. The mouse-human chimeric IgG was shown to have same sugar chains as those of mouse IgG.