Comparative Biochemical Characterization of a Human IgM Produced in Both Ascites and In vitro Cell Culture

Abstract
We have conducted a comparative analysis of a monoclonal human IgM obtained from cells cultured in nude-mouse ascites and from the same cells cultured in a bioreactor. We studied the glycosylation of the IgMs using lectin blotting and high-pH anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD), and we also developed reverse phase liquid chromatography (RPLC) peptide maps of the IgM samples. The HPAE-PAD data indicate that the samples differ in both the type and distribution of oligosaccharides present on the IgMs. In addition, the proteins differ in their solubility behavior and in their RPLC peptide maps. We conclude that the method of cell culture is capable of significantly altering the characteristics of the glycoprotein product.