Zielantigen

Zielantigen, literally “target antigen,” is the molecule or epitope that an immune receptor recognizes or that is selected as the therapeutic target in immunological interventions. In natural infection, the target antigen is a component of the pathogen that can be bound by antibodies or presented to T cells. In medicine, Zielantigene refer to antigens chosen to direct therapies such as monoclonal antibodies, CAR-T cells, cancer vaccines, or antibody–drug conjugates.

Discovery and selection involve identifying candidates that are expressed in diseased tissue while sparing essential normal tissues. Key criteria include specificity to the diseased state, adequate expression levels, and the ability to be presented by MHC molecules for T-cell responses or recognized by antibodies. Neoantigens from tumor mutations and tissue-specific tumor-associated antigens are common targets, while potential cross-reactivity and safety concerns must be assessed.

In therapeutic contexts, Zielantigen guide the design of diverse strategies. Monoclonal antibodies and antibody–drug conjugates target surface antigens; CAR-T and T-cell engaging therapies redirect immune cells to the target; cancer vaccines aim to elicit durable immunity against specific epitopes. Diagnostic applications use antigens to detect antibodies or to measure immune reactivity.

Challenges include tumor heterogeneity and antigen loss, risk of on-target off-tumor toxicity, and restricted antigen accessibility or presentation. Ongoing research emphasizes better target discovery, multiplex targeting to address heterogeneity, and safer, more selective delivery of therapies.