Monoclonal antibodies are highly specific for antigens of interest, and have been widely used for many purposes. For their generation, antigen-sensitized B lymphocytes need to be somatically fused with cancerous cells to give rise to hybridoma cells that can continuously secrete the targeted monoclonal antibodies. Several protocols using viruses, or chemical and physical approach have been established. With conventional means, however, efficiency is very low because of the failure to control cell fusion of targeted B lymphocytes with myeloma cells. To address this problem, we have developed a new technology, termed antigen-based B-cell targeting, which features obvious advantages over the conventional methods. It confers at least a 5-40-fold increase in efficiency over that obtained with the poly(ethylene glycol)(PEG)-mediated method. A particular feature is that sensitized B lymphocytes can be stringently isolated in advance based on immunoglobulin receptors on B lymphocytes, so that antigen-selected B lymphocytes and myeloma cell complexes can be preferentially fused by electrical pulses. This antigen-based novel technology allows rapid production of monoclonal antibodies based on in vitro immunization, and also selective production of conformation-specific monoclonal antibodies against antigens with native structure.