4-1BB agonist as well as preparation method and application thereof

The invention discloses a 4-1BB agonist which is a fusion protein comprising an anti-FAP antibody and 4-1BBL, the anti-FAP antibody is scFv and comprises VL with an amino acid sequence as shown in SEQ ID NO: 1 or the identity of the VL with the SEQ ID NO: 1 being at least 90% and VH with an amino acid sequence as shown in SEQ ID NO: 3 or the identity of the VH with the SEQ ID NO: 3 being at least 90%. The invention also discloses an isolated nucleic acid for coding the 4-1BB agonist, a recombinant expression vector, a transformant or a pharmaceutical composition containing the isolated nucleic acid, and application of the isolated nucleic acid in preparation of medicines for treating tumors. According to the invention, local immune activation of the tumor is realized; mediation activation caused by Fc fusion is avoided, and molecules are safer; and a monovalent 4-1BBL is also used, so that the risk of the 4-1BBL in production and immunogenicity is avoided. 本发明公开了一种4-1BB激动剂，其为包括抗FAP抗体与4-1BBL的融合蛋白，其中，所述的抗FAP抗体为