A compound which may comprise a ligand which binds, directly or indirectly, specifically to an antigen of a pathogen, provided that said ligand is not the PRYSPRY domain of TRIM21; and a RING domain and/or an inducer of TRIM21 expression.直接的または間接的に病原体の抗原に特異的に結合するリガンドと、ただし、TRIM21のPRYSPRYドメインではなく、RINGドメインおよび/またはTRIM21発現の誘導因子とを含む化合物。