Receptor binding specificity was compared to receptor-specific infection efficiency by plotting, for both, the 2-3Sia/2-6Sia ratio derived from ST3Gal4-and ST6Gal1-transfected HEKΔSiaN, HEKΔSiaO, HEKΔSiaGSL, and HEKΔSia cells. The gene discussed is ST6GAL1; the disease is infection.