New Strategies to Establish Human Monoclonal Antibodies.

Abstract

In order to establish human monoclonal antibodies to any sort of antigens efficiently, we have made following two approaches. Our first approach is to improve cell fusion frequency. By improving our previous method for production of human hybridomas, we obtained higher frequency (1/700 vs. 1/ 5500) compared with our previous method by adding irradiated myeloma cells to culture of fusion cells and modifying the selective medium. Our second approach is to use a SCID-hu mouse for immunization. Since the injection of human PBL can result in the stable long-term reconstitution of a human immune system in SCID mouse, we tried to immune SCID-hu mouse with KLH. In the serum of immunized SCID-hu mouse, we obtained human IgG antibodies to KLH. Additionally, we succeeded in establishing human B lymphoblastoid cell lines which produced antibodies specific to KLH. These methods will open new prospects for the detection and therapy of cancer.human monoclonal antibody ; SCID-hu mouse ; GIT medium ; cell fusionThe need for the efficient production of human monoclonal antibodies to tumor-specific antigens is increasing. Compared with the establishment of the regular mouse monoclonal antibody, that of human monoclonal antibody to any sort of antigens is technically very difficult. This is mainly because (1) fusion frequency to establish human hybridomas is very low, and (2) immunization of humans with any sort of antigens is dangerous. In order to break down these obstacles, as a first approach, we tried to improve fusion frequency. As a second approach, we used SCID-hu mouse for immunization, as SCID-hu mouse could reconstitute a human immune system. MATERIALS AND METHODS(Mouse x human) heteromyeloma (SHM-D33) and GIT culture medium used for cell fusion experiments (Kudo et al. 1988).Address for reprints : 4-1 Seiryomachi, Aoba-ku, Sendai 980, Japan. 323were mainly

Production of a Human Monoclonal Antibody to a Synthetic Peptide by Active In Vivo Immunization Using a SCID Mouse Grafted with Human Lymphocytes.

“…By immunizing a PBL-SCID mouse with antigens, we could obtain human antibodies specific to these antigens in the mouse serum. From the various lymphoid organs of an immunized PBL-SCID mouse, we succeeded in establishing human B lymphoblastoid cell lines which secreted human IgG, IgM, and IgA specific to the antigen (Kudo et al 1992). These observations inspired us to produce human monoclonal antibodies by cell fusion between spleen cells obtained from an immunized PBL-SCID mouse and myeloma cells.…”