Anti–TLT-1 antibody prevents the platelet-induced suppression of patient CD8 T cells. (A and B) The clinical profiles of studied NSCLC patients were screened for hematology reports and absolute lymphocyte count (A) as well as LMR (B) were recorded for individual patients at the closest date to recruitment and sampling. The obtained values were plotted as x–y correlation plots (A and B) with surface TLT-1 levels measured in those patients. An inverse relationship of surface TLT-1 was found with both these lymphocyte-based parameters. The Pearson’s coefficient is shown. (C) The schematic shows the experimental strategy followed for studying the role of platelet-released TLT-1 in T cell exhaustion by coculture of NSCLC patient platelets with T cells. The magnetic bead–based negative selection kit was used to isolate T cells from patient blood. (D) Live T cell numbers after coculture of platelets with T cells from NSCLC patients in presence of anti–TLT-1 antibody or isotype control (cAb) antibody. A control group with NSCLC T cells only and no platelets is also shown. Quantitations are presented as scatter graphs with mean ± SEM, and the significant differences indicated by asterisk correspond to Kruskal–Wallis test followed by Dunn’s multiple comparisons. (E and F) The FC-based analysis of T cells (n = 4) from coculture experiment shows the fraction of CD8 cells (layout gates), or CD4 T cells (F) in the three groups. The representative contour plots (n = 4) were the result of gating on lymphocyte proportion. The FC gates show the % cells. Significant differences are indicated with asterisks (*, P < 0.05). All experimental data represent minimum of three independent experiments.