Herein is reported a method for the generation of multispecific antibodies directly on the cell-surface at the site of action by a half-antibody exchange reaction between two 2/3-IgGs or two 2/3-BiFabs destabilized in one half by asymmetric perturbing mutations fostering the generation of correctly assembled full length bi- or multi-specific antibodies. The method is performed in the absence hinge region disulfide bonds in the starting 2/3-IgGs or 2/3-BiFabs.本文中報導一種直接在細胞表面上、在作用位點處產生多特異性抗體的方法,此藉由兩個2/3-IgG或兩個2/3-BiFab之間的半抗體交換反應來達成,該兩個2/3-IgG或兩個2/3-BiFab的一半藉由不對稱擾動突變而失去穩定,從而促進正確組裝的全長雙特異性或多特異性抗體產生。該方法係在初始2/3-IgG或2/3-BiFab缺乏鉸鏈區二硫鍵的情況下進行。