King cobra (Ophiophagus hannah) venom comprises a diverse array of proteins and peptides. However, the roles and properties of these individual components are still not fully understood. Among these, Cysteine-rich secretory proteins (CRiSPs) are recognized but not fully characterized. This study investigates the biological effects of Opharin, the CRiSP from king cobra venom (KCV). The effects of Opharin on cytokine production, specifically on IL-1β, IL-6, IL-8, TNF-α, and IL-10 release, were evaluated over 24 h in monocyte-derived macrophage (MDM) cells. Notably, the levels of these inflammatory cytokines were significantly increased over 24 h, with values higher than those observed in cells treated with crude KCV at most time points. Additionally, the in vivo Miles assay in mice revealed that Opharin increased vascular permeability by 26% compared to the negative control group. These findings highlight the Opharin's role in severe inflammatory and vascular responses observed in king cobra envenomation. Still, further research is essential to elucidate the pharmacological and toxicological effects of venom components, ultimately enhancing the clinical management of envenomation.
Keywords: inflammatory cytokines; king cobra venom; monocyte-derived macrophages (MDM); opharin; vascular permeability.