Figure 2.

Wuhan-Hu-1 and β-1.351 strain spike proteins dose-dependently reduce cAMP-activated CFTR chloride channel activity in differentiated BCi.NS1.1 (d-BCi) epithelia. (a) ALI differentiated dBCi cells were incubated apically with different concentrations of Wuhan-Hu-1 [S1S2] spike protein for 4 h, washed and then incubated for additional 20 h under ALI conditions. CFTR-dependent short-circuit currents (I_sc) were measured in Ussing Chambers as the changes in response to Amiloride, IBMX/Forskolin, and CFTR_inh-172. Representative I_sc tracings (panel top) and summary of changes in I_sc of four independent Ussing chamber experiments (bottom panel) are shown. (b) dBCi cells were incubated with different concentrations of β-1.351 [S1S2] spike protein and CFTR-dependent I_sc was analyzed as in part (a). The data are expressed as means ± SD (N = 4). Statistical p values were determined with a one-way ANOVA, followed by both Holm’s and Dunnett’s post-hoc tests comparing each mean to the medium control for the Holm test, *, p < 0.05; and ¥, p < 0.01. Dunnett’s tests were consistently significant (p < 0.05), except as noted (•).