Figure 5.
Valproic acid inhibits IFN-γ-producing NK cells during Listeria monocytogenes infection in vitro. 1 × 106 Splenocytes from healthy BALB/c mice were pre-incubated 1 h with VPA and then co-cultured with L.m at a MOI of 0.1:1. (A) IFN-γ level in cell supernatants was evaluated by ELISA 24 hpi n = 9 per group; ***p < 0.001 VPA + L.m vs L.m groups; Untr., Untreated cells). (B) Splenocytes were infected with L.m and 18 hpi cells were stained and analyzed by flow cytometry. Graph depicts the fold increase in numbers of IFN-γ producing cells upon infection with L.m, compared to uninfected cultures. The box shows the statistical significance between different immune cell populations compared to NK cells. (n = 6 per group). (C) Representative flow cytometry zebra-plots showing the frequency of CD3-CD49b + IFN-γ producing NK cells. Splenocytes were left uninfected, treated with VPA only or infected with L.m in presence or absence of VPA. (D) Percentage of IFN-γ + NK cells. (n = 6 per group; ***p < 0.001 between VPA + L.m vs L.m groups; Untr., Untreated cells). Data are expressed as median and range; Kruskal–Wallis.