The present invention relates to a cytotoxic agent for the prophylaxis and/or treatment of a viral infection which is configured for the selective binding to a membrane receptor of virus-infected T lymphocytes, a pharmaceutical composition containing said cytotoxic agent, the use of the cytotoxic agent for the prophylaxis and/or treatment of viral infections, a method of finding cytotoxic agents, the use of a membrane receptor of virus-infected T lymphocytes which is overexpressed in comparison to non-infected T lymphocytes for the diagnosis of a viral infection.
