FIG. 3.

Low pH-induced coflotation of TBEV with liposomes in the absence or presence of MAbs. TBEV virions were preincubated with each of the MAbs overnight at 4°C, liposomes were added, and the mixture was acidified, back-neutralized, and then subjected to centrifugation in sucrose step gradients. (A) Representative examples of coflotation experiments. From left, panel 1, coflotation without MAb (No mab) at pH 5.4 (solid line) and pH 7.4 (dotted line). Panels 2 to 4, coflotation in the presence of MAbs at pH 5.4. B2 (panel 2; no effect), A3 (panel 3; strong effect), and A2 (panel 4; intermediate effect). (B) Results of coflotation experiments with each of the MAbs, expressed as percentages of E protein bound to liposomes at pH 5.4 in comparison to the control without a MAb. The data are the averages from at least two independent experiments; the error bars represent the standard errors of the means.