Targeted immunosuppressant TCABCD59 for preventing and treating infectious inflammation

The invention discloses a targeted complement inhibitor fusion protein C3d-ScFv-CD59 of a single-chain antibody of a human anti-complement C3d molecule and a complement inhibitor CD59. The fusion protein has excellent antigen binding activity, and in-vitro inhibition experiments show that C3d-ScFv-CD59 has a more obvious inhibition effect corresponding to a single effector molecule CD59, and the effect is realized by identifying that the C3d component in a complement activation region plays a complement inhibition role. The C3d-ScFv-CD59 is used for treating influenza/bacteria co-infected mice, the survival rate is obviously increased, lung lesions are obviously relieved, the targeted complement inhibition effect is obvious, and the C3d-ScFv-CD59 has an obvious treatment effect compared with the single effector molecule CD59, and it proves that the fusion protein provided by the invention has an excellent application prospect in preparation of drugs for treating influenza virus and bacteria co-infected pneumo