IL-16 exerts anti-rabies virus effects through CD9 on the surface of viral particles.

Rabies, caused by the rabies virus (RABV; scientific name Rabies lyssavirus), is invariably fatal, and currently, there is no specific drug for its treatment. Previous studies have demonstrated the relationship between CD9 and the RABV. However, it remains unclear whether CD9 and IL-16 affect the RABV life cycle. To verify the role of CD9 and IL-16 in the life cycle of the RABV and further explore drugs that can inhibit RABV replication. We examined the effects of overexpression or underexpression of CD9 and IL-16 on the RABV replication process. Subsequently, adeno-associated virus (AAV) vector-delivered single-chain antibodies against RABV glycoprotein (RABV-G) or IL-16, were utilized to specifically inhibit RABV replication and explore their therapeutic potential in a mouse model of rabies. Our study revealed that the CD9 protein significantly affected RABV replication in cells. Also, IL-16 could effectively inhibited the RABV replication in vitro and prolonged mouse survival in vivo. Single-chain antibodies against RABV and IL-16, delivered by AAV vectors carrying exocytotic peptides and membrane-penetrating peptides, inhibited RABV proliferation in vitro, and suppressed RABV replication in mice in vivo. The tetraspanin CD9 facilitates RABV infection, and like the RABV-G, it may also be a good therapeutic target for RABV infection. The CD9 ligand molecule IL-16 and single-chain antibodies against RABV carried by AAV delivery system are promising therapeutic approaches for RABV infection.