Dual Targeting Engineered Binding Proteins Block SARS-CoV-2 Infection and Complement Activation

The rapid evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and associated complement overactivation challenge current antiviral strategies that mainly target viral entry. This study aimed to develop dual targeting engineered binding proteins capable of simultaneously blocking viral infection and complement activation. Two proteins, SBP10 and SBP16, were engineered by integrating an ACE2-mimicking peptide with a mannose-binding lectin (MBL) domain. Binding affinity and antiviral activity were evaluated using biochemical and functional assays, including inhibition of S protein-ACE2 interaction, neutralization of multiple SARS-CoV-2 variants, and assessment of lectin pathway-mediated complement activation. Both SBP10 and SBP16 bound the spike protein with low-nanomolar affinity and effectively blocked its interaction with ACE2. The proteins exhibited broad-spectrum neutralizing activity against several variants, including Alpha, Beta, Delta, and Omicron. Moreover, they significantly suppressed spike-induced activation of the lectin complement pathway. In vivo experiments further demonstrated that treatment with SBP10 or SBP16 markedly reduced spike protein-induced lung injury. In conclusion, SBP10 and SBP16 function as dual targeting engineered binding proteins that inhibit viral entry while attenuating complement-mediated inflammation, highlighting a promising therapeutic strategy for controlling SARS-CoV-2 infection and its associated immune dysregulation.