A modular antigen-transporting molecule (MAT) comprising one each of a translocation module (TrM), a targeting module (TaM) and an antigen module (AM), is new. Modular antigen-transporting molecule (MAT) comprising at least one each of translocation module (TrM), targeting module (TaM) and antigen module (AM) is new. TrM is able to transport MAT from the extracellular space into a cell TaM directs transport of MAT to organelles involved in processing of antigens (Ag) or loading of MHC (major histocompatibility complex) molecules, and AM determines the specificity of the immune response induced by MAT. Independent claims are also included for the following: (1) method for preparing MAT (2) nucleic acid (I) that encodes MAT (3) vector containing (I) and preferably at least one of promoter, antibiotic or antimycotic resistance gene (4) primary cells or cell lines containing a vector of (3) or (I) (5) vesicles, especially exosomes, deoxosomes or liposomes that contain at least one MAT, (I) or the vector of (3) (6) immunoglobulins (Ig), or their fragments, that recognize MAT, prepared by immunization of a human or animal (7) method for identifying substances that inhibit or stimulate presentation of Ag through the MHC (8) method for identifying specific epitopes of Ag (9) in vitro cultured cells, human or animal, that have been treated with MAT, (I), the vector of (3) or vesicle of (5) and show modulated Ag presentation and (10) method for preparing antibodies (Ab), using MAT, (I), vesicles of (5), or cells of (4) or (9), by immunization.
