Effect of T lymphocyte-LN MSC coculture on anti–lymphoma cytotoxicity. CD8⁺αβT or γδT lymphocytes, Vδ1 or Vδ2 as indicated, were used as effector cells, whereas the RS773 (A,C,E) and the KM-H2 Hodgkin RS-like cell lines (B,D,F), either untreated or pretreated for 48 hours with 2.5mM VPA (C-F), were used as targets in a 4-hour ⁵¹Cr-release assay at the E:T ratios of 10:1. In some experiments, the effector T lymphocytes were precultured on LN MSCs for 5 days before using in cytolytic assay. In some experiments (E-F), the soluble NKG2D receptor (NKG2D-Fc) or the anti–TGF-β mAb (5 μg/mL) was added to lymphocyte-LN MSCs cocultures; then effector cells washed and used in cytolytic assay. In all cytotoxicity experiments, a blocking anti–NKG2D specific mAb (5 μg/mL) was used compared with an unrelated, isotype-matched mAb. (A-D) Subpanel i shows the reactivity of the soluble NKG2D receptor (NKG2D Fc), evidenced with a PE-goat anti–human, to the RS773 or KM-H2 cell lines before (Ai,Bi) or after VPA exposure (Ci,Di). Results are expressed as percentage of specific cell lysis and are the mean ± SD from 6 experiments performed with 6 different LN MSCs. (Cii,Dii) *P < .001 versus RS773 in panel Aii and versus KM-H2 in panel Bii. **P < .001 versus cytolytic activity of effector cells in the absence of anti–NKG2D mAb. (E-F) *P < .001 versus cell lysis exerted by CD8⁺ T lymphocytes before LN MSC coculture and/or in the absence of anti–NKG2D mAb. **P < .001 versus cytolytic activity exerted by CD8⁺ T lymphocytes after LN MSC coculture.