Idiotypic Antibody Network Regarding Malignant Cell Regression in the Brain Tumor Patients Treated with the Natural Human Monoclonal Antibody, Pritumumab

Pritumumab is a natural human monoclonal antibody derived from a lymph node of a patient with cervical carcinoma. The recognized antigen is an altered form of vimentin called, ecto-domain vimentin (EDV) that is expressed on the cell surface of cancer cells. EDV is present on vimentin-exposing ectosomes (VEE) that are vesicular protrusions on the cell surface of cancer cells. Idio-33 is an antiparatactic idiotypic antibody of pritumumab that recognizes a p34Ag from glioma cells. During a Phase II clinical trial with brain tumor patients, Idio-33 was used to monitor serum levels of pritumumab (Ab1). In the treated patients, the paratope of pritumumab behaved as a mimotope of p34Ag that induced the expression of anti-anti-idiotypic antibody (Ab3). This Ab3 showed a rhythmic response like Lorenz chaotic attractor in good responders and not in poorly responding patients. The involvement of EDV and VEE in tumor immunity is complex but yet dynamic and may be involved in tumor stem cell regression.