Site-specific antibody conjugation and antibody-drug conjugate as specific example thereof

The present application relates to a technology enabling a specific number of chemical functional groups or cargo moieties to be labeled at specific sites of an antibody. An antibody product having high uniformity can be provided by the present application. In addition, an antibody product in which functions of the antibody do not decline can be provided by the present application. That is, an antibody product of which avidity and half-life do not decline can be provided. The present application is very meaningful by being the first technology that enables site-specific labeling of antibodies without a complicated process.