[Monoclonal immunotherapy with human monoclonal antibody(CLN-IgG) in glioma patients]

It is well recognized that malignant gliomas escape an immune response by hiding behind the blood-brain barrier and by producing proteins that suppress systemic immunity. However, if gliomas can be made to be more immunogenic or if a tumor vaccine can be produced, then access to all tumor cells including those that infiltrate into the brain can be achieved through the patient's immune response. Several strategies have been investigated for immunotherapy. Laboratory studies and animal models have shown that these immune cells will attack the tumor cell, reduce the size of implanted tumors, and that the immune memory is sufficient to suppress tumor growth when the animal is rechallenges with a tumor implant. Since the development of hybridoma technology, monoclonal antibodies against human cancer cells have been produced and antigens have been identified. Hagiwara reported the production of a human monoclonal antibody, CLN-IgG, made by fusing UC 729-6, human lymphoblastoid B-cell line, with lymphocytes obtained from a patient with the cervical carcinoma. It has been reported that CLN-IgG recognized the antigen expressed in various histological types of human cancers including malignant gliomas. The effect of human monoclonal antibody(CLN-IgG) on malignant brain tumors was evaluated in patients with malignant glioma. Early phase II study was concluded that this specific immunotherapy with CLN-IgG is safe and effective therapy in patients with malignant glioma. We treated 10 cases of malignant gliomas with CLN-IgG. All patients had received radiotherapy and chemotherapy before this immunotherapy using the human monoclonal antibody. The human monoclonal antibody(CLN-IgG) was administered intravenously once or twice/week during 24 weeks. Six cases of glioblastoma, 1 medulloblastoma and 3 cases of potine glioma histologically unverified, were treated. Five cases of 6 glioblastomas died 4 to 12 months after this treatment, 3 cases of pontine glioma showed good responses, 2 cases showed marked decrease of tumor size and 1 case showed no regrowth of tumor on MRI imaging. For the above reasons, Human monoclonal antibody(CLN-IgG) might be useful as an immunotherapy of malignant gliomas.