Fig. 2.

Inhibition of the S protein-mediated cell fusion by HR2 and HR1 peptides. (A) The cell fusion assay and (B) syncytia formation. β-Galactosidase activities were measured for co-cultured HeLa cells #1, cells #2 and various controls with (+) or without (−) transfection and/or infection. Syncytia formation was observed under light microscope. (C) Inhibitory effects of HR2 peptides (P1–P7) at high concentrations (25 and 9 μM). (D, E) Inhibitory effects of HR2 peptides (P1, P4 and P6), HR1 peptides (N46, N46eg) and their combination (N46 plus N46eg, molar ratio 1:1) at various concentrations. Data are means ± standard errors of duplicate wells. One representative experiment of more than three is shown.