FIG. 2.

Resistance of clones to virus-induced lysis did not depend on CD155 expression. The level of CD155 expression at the surface of Caco-2 (circles), cl6 (squares), and b13 (triangles) cells was determined by indirect immunofluorescence, and the mean fluorescence per positive cell was quantified by flow cytometry in arbitrary units 1 to 6 days after cell passage by trypsinization (a). The ratio of CD155 to ICAM-1 expression, used as a reference, is shown for the three cell types (b). (c) Partial resistance of Caco-2 cell-derived clones cl6 and b13 to cell lysis after infection with coxsackievirus B3 (CVB3). Caco-2 (dark gray), cl6 (light gray), and b13 (white) cells were infected at an MOI of 10⁻² ID₅₀/cell, and the number of surviving cells was determined by trypan blue exclusion 2 days p.i. The results are means ± SEM from at least four cultures from two independent experiments.