Recombinant Human Anti-SARS S Antibody (80R) (CAT#: PABZ-139)

Figure 1 Microneutralization assay of anti-S1 antibodies on SARS-CoV.

(A) Microneutralization assay of anti-S1 scFvs. The positive control was convalescent serum from a SARS patient; the negative control was non-SARS human serum. The names of the scFvs are labeled at the top, and antibody titers are indicated on the left. Neutralizing scFv 80R and only one nonneutralizing scFv 27D (illustrative of the other nonneutralizing scFvs) are shown. Undiluted SARS-CoV ( ~37 plaque-forming units) was loaded per well. (B) Comparison of the neutralization activity of 80R scFv and full-length 80R IgG1. The positive and negative control serum samples and the amount of virus used were the same as in A. The titer and concentration of antibodies are labeled on the left.

Sui, J., Li, W., Murakami, A., Tamin, A., Matthews, L. J., Wong, S. K., ... & Anderson, L. J. (2004). Potent neutralization of severe acute respiratory syndrome (SARS) coronavirus by a human mAb to S1 protein that blocks receptor association. Proceedings of the National Academy of Sciences, 101(8), 2536-2541.

Figure 2 Kinetic rates and binding affinity of 80R antibody and ACE2 to S1-lg

Sui, J., Li, W., Murakami, A., Tamin, A., Matthews, L. J., Wong, S. K., ... & Anderson, L. J. (2004). Potent neutralization of severe acute respiratory syndrome (SARS) coronavirus by a human mAb to S1 protein that blocks receptor association. Proceedings of the National Academy of Sciences, 101(8), 2536-2541.

Figure 3 Inhibition of syncytia formation by anti-S1 antibodies.

Shown is syncytia formation assay with anti-S1 antibodies. 293T cells expressing SARS-CoV S protein were preincubated with the indicated concentrations of anti-S1 scFvs or 80R IgG1 and then mixed with 293T cells expressing ACE2. After culturing for 36 h in the presence of antibodies, dose-dependent inhibition of syncytia formation by 80R scFv, 80R IgG1 was observed and photographed. Representative results are shown.

Sui, J., Li, W., Murakami, A., Tamin, A., Matthews, L. J., Wong, S. K., ... & Anderson, L. J. (2004). Potent neutralization of severe acute respiratory syndrome (SARS) coronavirus by a human mAb to S1 protein that blocks receptor association. Proceedings of the National Academy of Sciences, 101(8), 2536-2541.

Figure 4 80R scFv inhibiting the binding of S1 to ACE2 receptor.

(A) Flow cytometry histograms; shown is staining Vero E6 with S1-Ig and flow cytometry analysis. Dotted line, control staining with S1 (327)-Ig; thin line, cells were stained with S1-Ig; bold line, staining with premix of 0.3 μg of S1-Ig and 0.3 μg of 80R scFv (Left) or 27D scFv (Right). (B) scFv competition of S1-Ig binding to ACE2 in immunoprecipitation. Radiolabeled ACE2 was immunoprecipitated by S1-Ig that was preincubated with the indicated amounts of either 27D scFv or 80R scFv. Anti-ACE2 precipitates were used as a positive control. Immunoprecipitates were run on a reducing SDS-PAGE gel and visualized by autoradiography.

Sui, J., Li, W., Murakami, A., Tamin, A., Matthews, L. J., Wong, S. K., ... & Anderson, L. J. (2004). Potent neutralization of severe acute respiratory syndrome (SARS) coronavirus by a human mAb to S1 protein that blocks receptor association. Proceedings of the National Academy of Sciences, 101(8), 2536-2541.

Figure 5 80R IgG1 neutralization of pseudoviral infection mediated by full-length SARS-CoV spike variants.

HIVs pseudotyped with the S protein from Tor2, SZ3, or GD03T isolates were incubated with the indicated concentration of 80R IgG1 (solid line, diamonds) or nonrelevant human IgG1 (solid line, squares) for 1 h prior to infection. At 48 h after infection, luciferase activities in target cells were measured and relative viral inhibition was calculated as the ratio of luciferase activity in the presence to absence of 80R IgG1 or nonrelevant human IgG1. (a) 80R IgG1 efficiently blocked Tor2 S protein-pseudotyped HIV infection, with a 90% inhibitory concentration around 2 μg/ml. (b) 80R IgG1 also efficiently neutralized SZ3 S protein pseudoviral infection. (c) In contrast to Tor2 and SZ3, GD03T S protein-pseudotyped virus was essentially resistant to the neutralization of 80R IgG1 with a concentration up to 50 μg/ml. These results are representative of two experiments with similar results.

Sui, J., Li, W., Roberts, A., Matthews, L. J., Murakami, A., Vogel, L., ... & Marasco, W. A. (2005). Evaluation of human monoclonal antibody 80R for immunoprophylaxis of severe acute respiratory syndrome by an animal study, epitope mapping, and analysis of spike variants. Journal of virology, 79(10), 5900-5906.