Attention to therapeutic monoclonal antibodies has been dramatically increasing year by year. Their highly specific targeting of antigens can provide very effective medical treatment, and the advent of molecular-targeting medicine is allowing development of a new generation of therapeutic agents. However, there is one critical obstacle to overcome. Most of the established therapeutic monoclonal antibodies have specificity for the primary structures of target antigens, although all proteins harbor original native intact structures for their own specific functions. Stereo-specific monoclonal antibodies recognizing conformational structures of target antigens may thus offer a markedly more versatile approach. Their application may change the very concepts underlying use of therapeutic antibodies.

Hybridoma technology features effective usage of innate functions of both immune cells and cancers, allowing production of hybridoma cells, which continuously generate monoclonal antibodies specific to antigens of interest. For standard generation of hybridoma cells, B lymphocytes must be somatically fused with myeloma cells using various technologies. However, the methods generally do not necessarily result in selective fusion of target B lymphocytes with myeloma cells. To overcome this problem, we have developed a new hybridoma technology that involves preselection of B lymphocytes with target antigens based on immunoglobulin receptors and selective fusion of B cell-myeloma cell complexes with electrical pulses. The advanced methodology, termed B-cell targeting, multitargeting and stereospecific targeting, may be applicable to simultaneous production of monoclonal antibodies, selective production of stereospecific monoclonal antibodies, and also to efficient generation of human monoclonal antibodies for clinical purposes.

The effect of binary hydrophilic polymers on a pair of representative bio‐macromolecules in a living cell has been examined. The results showed that these bio‐macromolecules exhibited specific localization in cell‐sized droplets that were spontaneously formed through water/water microphase segregation under crowding conditions with coexisting polymers. In these experiments, a simple binary polymer system with poly(ethylene glycol) (PEG) and dextran (DEX) was used. Under the conditions of microphase segregation, DNA was entrapped within cell‐sized droplets rich in DEX. Similarly, F‐actin, linearly polymerized actin, was entrapped specifically within microdroplets rich in DEX, whereas G‐actin, a monomeric actin, was distributed evenly inside and outside these droplets. This study has been extended to a system with both F‐actin and DNA, and it was found that DNA molecules were localized separately from aligned F‐actin proteins to create microdomains inside microdroplets, reflecting the self‐emergence of a cellular morphology similar to a stage of cell division.