Figure 7.

HMBA impairs the capacity of NK cells to suppress latently HIV-infected CD4⁺ T cells harboring PRO-reactivated virus. (A) The expression of NKG2D on NK cells not treated or exposed to HMBA, PRO, or HMBA + PRO for 18 h was measured as % of positive cells and NKG2D MFI (mean ± SEM, n = 3). (B–D) A co-culture assay of latently infected CD4⁺ T cells at day 2 post-stimulation with 1 μM PRO alone or in combination with 5 mM HMBA and autologous NK cells at a 1:1 E:T ratio was performed overnight (18 h) in the presence of the same drug(s). Then, cells were analyzed to measure the frequency of p24⁺ cells among gated CD3⁺ targets and calculate % reduction of 24⁺ targets by NK cells. (B) The CD3⁺ cell gate was set on cultures of targets alone, so that effectors cells were excluded, as shown in control cultures of effectors alone as well as in co-cultures of targets and effectors in a representative experiment. (C) A representative set of results for nt, PRO-, and HMBA + PRO-exposed cultures is shown. (D) The NK cell mediated clearance of p24⁺ cells was measured in 3 independent experiments and expressed as % 24⁺ killing (mean ± SEM) as described in Materials and Methods. Each symbol represents 1 donor. *P < 0.05, **P < 0.01 by two-tailed paired t test.