Send to

Choose Destination
MAbs. 2011 Nov-Dec;3(6):505-12. doi: 10.4161/mabs.3.6.18090. Epub 2011 Nov 1.

An innovative approach for the characterization of the isoforms of a monoclonal antibody product.

Author information

Bioanalytical Science, ImClone Systems, Branchburg, NJ, USA.


Protein biopharmaceuticals, such as monoclonal antibodies (mAbs) are widely used for the prevention and treatment of various diseases. The complex and lengthy upstream and downstream production methods of the antibodies make them susceptible to physical and chemical modifications. Several IgG1 immunoglobulins are used as medical agents for the treatment of colon, breast, and head and neck cancers, and at least four to eight isoforms exist in the products. The regulatory agencies understand the complex nature of the antibody molecules and allow the manufactures to set their own specifications for lot release, provided the safety and efficacy of the products are established in animal models prior to clinical trials. During the manufacture of a mAb product, we observed lot-to-lot variability in the isoform content and, although the variability is within the set specifications for lot release, made attempts to gain mechanistic insight by isolating and characterizing the individual isoforms. Matrix-assisted laser desorption/ionization (MALDI) and liquid chromatography (LC)/mass spectrometry (MS)/MS analyses of the isolated isoforms indicate that this variability is caused by sialic acid content, as well as truncation of C-terminal lysine of the individual isoforms. Sialidase and carboxypeptidase treatment of the product confirm the observations made by MALDI and LC/MS/MS.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Taylor & Francis Icon for PubMed Central
Loading ...
Support Center