Targeting conserved interaction surfaces of alphavirus nsP4 supports the rational design of live-attenuated vaccine candidates.

Mutations in conserved nsP4 interaction sites can attenuate alphavirus replication and pathogenicity, with F164A, K174S, and D393A showing significant effects in models.

• Why it matters: Alphaviruses pose a growing global health threat with limited vaccine options, and targeting conserved viral components like nsP4 offers a promising strategy for vaccine development and antiviral therapies.
• What they did: Researchers evaluated 58 structure-guided mutations in nsP4 predicted to disrupt interactions with nsP1, nsP2, or viral RNA using a trans-replicase system, then further analyzed 16 mutations in viral chimeras and in vivo models.
• The result: Mutations affecting nsP4 interaction sites led to attenuation of viral replication and pathogenicity, with some variants like F164A being avirulent and immunogenic, supporting the design of live-attenuated vaccines targeting nsP4.