Analysis of hybridoma and CHO-derived pritumumab for therapeutic applications.

71Background: Pritumumab, a natural huma IgG1 kappa antibody was obtained from a regional draining lymph node of a patient with cervical carcinoma through traditional hybridoma technology. Methods: Both cell lines and tissues were processed and analyzed for FACS analysis, Western blots, and immunohistochemistry. Results: Specificity analysis of the target antigen, an altered form of vimentin (ecto-domain vimentin (EDV)) shows it to be limited to cell surface expression on cancer cells. Clinically, 249 Japanese brain cancer patients were treated with a low dose pritumumab regimen, either at 1mg once a week or 1mg twice a week, and overall response rates of between 25-30% were seen with several complete and partial responses. A recombinant version of the mAb was made using the GPEx system in CHO cells. In a series of comparable studies the CHO mAb was compared with the original hybridoma. Binding specificity with both flow cytometry and immunohistochemical (IHC) analysis, Western blot analysis, and Antibody...