Alterations in immunophenotype of cultured human CD34^pos bone marrow cells and peripheral blood monocytes in the presence of CI A23187 or rhCD40L. Cultures of CD34^posbone marrow cells previously expanded for 6 days in the presence of cytokines (see Fig 5) were replated and cultured for an additional 20 hours in the same medium without rh-c-kit ligand with various doses of CI A23187 or rhCD40L added. In synchronous experiments, elutriated monocytes were washed and plated overnight as described in Materials and Methods, then cultured for an additional 20 hours with no additive or CI A23187 or rhCD40L. After the 20-hour treatment bone marrow progenitors and monocytes were harvested and stained with PE-conjugated antibodies against human B7.1, B7.2, and CD83 and analyzed by FACS (see Materials and Methods). Representative displayed data depict untreated cells, cells treated with an optimal dose of CI (375 ng/mL for CD34^pos cells and 225 ng/mL for monocytes), or cells treated with 10 μg/mL rhCD40L. Similar results were observed in either cultured CD34^pos progenitors or peripheral blood monocytes treated with 2.5 or 40 μg/mL doses of rhCD40L (not shown).