Cytolysin binds to the target cell's surface receptor (glycoprotein, carbohydrate, or lipid) . The subdomains of the cell membrane that contain cholesterol are frequently referred to as lipid "rafts" . The transport of macromolecules into malaria-infected cells is facilitated by lipid rafts . Experiments with cholesterol-depleted red blood cells demonstrated that red blood cells become resistant to parasite invasion after depletion. It implies a role for lipid rafts in parasite invasion. Lecithin and cholesterol are critical components of the cell membrane of red blood cells, where they react with viral hemolysin . Cholesterol-dependent cytolysin (CDC) is a MACPF superfamily member. Cytolysin can create holes (25-30 nanometers in diameter) in the cell membrane where cholesterol is present . However, cholesterol is not required for this cytolysin to adhere to target cells . The cytolysin is oxygen-sensitive , and its activity decreases in a high-oxygen environment . Cholesterol promotes the fusion and infection of the alphaviruses Semliki Forest virus (SFV) and Sindbis virus significantly . SFV's E1 fusion protein binds to cholesterol . However, numerous dengue virus (DV) fusions and infections with yellow fever virus 17D are unrelated to cholesterol . The DV fusion protein exhibits no detectable cholesterol-binding activity . Cholesterol-dependent cytolysin may activate their hemolysin activity in hypoxic COVID-19 patients.