A heat-stable soluble components) is present in standard cotton dust (obtained from Cotton, Inc.) which with time causes cultured cells (myeloiod or lymphoid) to lose cholesterol and accumulate Ca(i)(2+) (as measured with Fura 2). Time (4 hours and more) is required to produce this cotton effect. Agents which mimic these delayed effects of cotton include HIV, dexamethasone, organic solvents, Ca(i)(2+) ionophores, and oxidized cholesterols. Since these changes in cholesterol occur in the absence of external cholesterol and require time, it is likely that cotton, like dexamethasone or other oxidized sterols, is interfering with production or utilization of genomic messages for steroid biosynthesis. Whether or not this is the mechanism by which cotton dust produces the debilitating chronic bronchitis of byssinosis remains to be established.