FIG. 9.

Adenovirus-stimulated macrophage TNF-α expression in vitro does not occur in the presence of the Ca²⁺ chelator, BAPTA. RAW264.7 cells were evaluated for TNF-α expression and release 2 h after a 30-min in vitro exposure to adenovirus. All experiments were carried out in the absence (A) or presence (B) of Ca²⁺ in the culture medium. Cells were infected with adenovirus alone (+Ad) or in the presence of the intracellular Ca²⁺ chelator, BAPTA (+BAPTA +Ad) to demonstrate the effect of blocking intracellular calcium fluxes on adenovirus-stimulated TNF-α expression. Cells were exposed to HBSS (Control) alone as a negative control for spontaneous TNF-α release. Cells were treated with the calcium ionophore, A23187 in Ca²⁺-free or Ca²⁺-containing medium as controls to demonstrate the role of the extracellular Ca²⁺ in stimulation of TNF-α expression in RAW264.7 cells. As an additional positive control, cells were exposed to lipopolysaccharide and A23187 (+ LPS + A23187), a potent stimulus for TNF-α expression in RAW264.7 cells. As an additional control to demonstrate the blocking effect of BAPTA, LPS-A23187 stimulation was done in the presence of BAPTA (+BAPTA +LPS +A23187).