Surface expression of adhesion molecules on NB-4 cells in response to treatment with 100 nmol/L tRA for 72 hours. The surface expression of integrins (except β1 integrin) and their counterstructure were determined as described in Materials and Methods using indirect immunofluorescence. β1 integrin (CD29) expression was determined by direct immunofluorescence. As a negative control for indirect immunoflroescence, a nonspecific IgG was substituted in the first step and FITC conjugated goat anti-mouse IgG was used as the indirect reagent. FITC conjugated goat anti-mouse IgG alone was used as the negative control for direct staining. Representative histograms are presented that show surface expression on NB-4 cells (- - - -) and NB-4 cells exposed to 100 nmol/L tRA for 72 hours (⋅⋅⋅⋅⋅⋅) as compared with a negative control ( — ). The surface expression of (A) LFA-1, (B) Mac-1, (C) p150, (D) β2 subunit, (E) β1 subunit, (F ) VLA-4, (G) ICAM-1, (H) ICAM-2, and (I) ICAM-3 are shown. The fold increase in expression of these surface receptors is described in the text. Fold increase in text represents three separate experiments with all samples run in parallel.
