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. Author manuscript; available in PMC: 2013 Nov 7.
Published in final edited form as: J Immunol. 2013 Jan 4;190(3):10.4049/jimmunol.1200593. doi: 10.4049/jimmunol.1200593

FIGURE 8.

FIGURE 8

NK cell cytotoxicity is reduced by Hsp90 inhibition. The cytotoxic activity of untreated control (◆) or geldanamycin-treated (▲) NK cells was measured against multiple myeloma cell lines using a calcein-release assay. Target cells (MM1S, ARP) labeled with calcein-AM were incubated with effector cells (untreated NK cells, Hsp90 inhibitor–treated NK cells) at various E:T cell ratios. After 4-h incubation, the calcein release was measured in the supernatant. Maximum release was obtained from detergent-released target cell counts, and spontaneous release was obtained from target cell counts in the absence of effector cells. Cellular cytotoxicity was calculated, as described in Materials and Methods. Hsp90 inhibitor–treated NK cells showed a significant reduction in cytotoxic activity against both MM1S and ARP multiple myeloma cell lines as compared with untreated NK cells. The values represent the mean ± SE of three separate experiments using purified NK cells obtained from different individual donors.