Construction of phosphorylatable monoclonal antibody CC49 with a casein kinase II recognition site.

A phosphorylation site for casein kinase II was introduced into chimeric monoclonal antibody CC49 (MAb-chCC49) by site-specific mutation of the coding sequence. The phosphorylation site for the casein kinase II was positioned at the carboxyl terminus of the heavy chain constant region of the MAb-chCC49. The resultant modified MAb-chCC49CKII was expressed in NS0 cells and purified. The MAb-chCC49CKII protein was phosphorylated by casein kinase II with [gamma-32P]ATP to high radiospecific activity. The 32P-labeled MAb-chCC49CKII binds to cells expressing TAG-72 antigens. The introduction of the phosphorylation sites for casein kinase II into monoclonal antibodies (MAb) provides a new reagent for the diagnosis and treatment of cancers. This demonstrates that the casein kinase II recognition site can also be used to introduce phosphorylation sites into proteins.