Bispecific antibodies: design, therapy, perspectives

Sedykh, Sergey E; Prinz, Victor V; Buneva, Valentina N; Nevinsky, Georgy A

Bispecific antibodies: design, therapy, perspectives modification results in a generation of chimeric bispecific molecules. 59, 60 In 2012-2016, it was shown that the bispecific IgG molecules of all four subclasses are present in blood, 61 placenta, 62 and milk (IgG and sIgA) 63,64 of healthy donors. The explosive growth of publications on BsAb generation happened in the 1980s and 1990s, when preparations of mAbs obtained by hybridoma technology became available. In 1983, hybrid hybridomas, called quadromas, expressing two types of light and heavy chains simultaneously and producing BsAbs were described. 65 In 1985, bispecific Fab 2 was obtained by chemical cross-linking. 66 In 1987, Fab molecules were first cross-linked with thioesters. 67 In 1984, mAbs against the T-lymphocyte receptor and leukemia cell-line antigen were cross-linked with a heterobifunctional linker and it was shown that generated BsAbs attract T-lymphocytes and stimulate T-cell mediated cytotoxicity. 68 In 1985, a bispecific Fab 2 was constructed from HL fragments against human CD3 receptors and HL fragments against H2k mouse protein; the resulting construct directed cytotoxic human T-lymphocytes to murine tumor cells with surface KK antigen and destroyed them by an Ab-dependent cytotoxicity mechanism. 69 In 1987, it was shown that BsAbs containing HL fragments, anti-T-cell antigen receptors, and antihemagglutinin of influenza virus demonstrate aspecific cytotoxic T-lymphocyte-mediated lysis of infected cells. 70 A detailed review of BsAb development history has been published. 71 The first papers on perspectives on BsAbs in clinical use were published in the 1990s. In 1992, BsAbs were shown to direct monocytes (carriers of FcγRI) against CD15 + breast carcinoma cells PM81, acute myeloid leukemia, and smallcell lung and intestinal carcinoma. 72 In 1995, MDX210 BsAbs against FcγR1 on the surface of monocytes and macrophages and against HER2 + cells were described; the construct was clinically active in breast and ovarian tumors. 73, 74 Clinical studies of 2B1 specific against tumor cells expressing c-erbB-2 and cells bearing FcyRIII showed the possibility of BsAb-mediated targeted lysis of HER2 + cells (breast, intestine, lung, kidney, prostate cancer) by natural killers and phagocytes. 75 The first generation of BsAbs was obtained by chemical cross-linking or from hybridomas. Now, most BsAbs are generated by three methods: by chemical conjugation with crosslinkers, by somatic fusion of two hybridoma lines (quadroma), and by genetic (protein/cell) engineering. Large pharmacological and biotechnological companies are developing new techniques for therapeutic BsAb generation, and more than 60 different technological platforms have been developed in the last 15 years. 16 Depending on the production method and structure, BsAbs vary in the number of antigen-binding sites, geometry, half-life in the blood serum, and effector functions. According to the mechanism of action, most modern BsAbs undergoing preclinical and clinical studies are classified into four formats: BiTEs, dual-affinity retargeting Abs, homodimeric "knob-in-hole" Abs, and trifunctional BsAbs.