Figure 4. Combinations of HmAbs more efficiently inhibit the entry of SARS-CoV RBD surrogate clinical isolates.

Neutralizing HmAbs binding to different regions of S protein 4D4 (S1), 1F8 (HR1), 5E9 (HR2)) were tested for their ability to neutralize pseudoviruses in different combinations as well as individually at a concentration of 6.25 µg/ml each. The virus/Ab mixture was incubated for 1 hr at 37°C then added to 293/ACE2 stable cell line. Seventy two hours later, the virus entry was determined by luciferase expression. The percentage entry inhibitions by individual antibodies as well as combinations of antibodies were calculated. Error bars represent SD of representative experiment performed in triplicates. Statistical analysis was done using Student-t test, significant differences are indicated by asterisks,* p<0.05.