Total T cells were isolated from blood of another donor using CD3 MicroBeads (Miltenyi). 105 T cells (T) per well were incubated with stimulator cells (S) at T/S ratio of 10:1. Cells were incubated for 4 days, pulsed with 0.5 μCi 3H-thymidine (PerkinElmer, Boston,

MA, USA) per well for the last PLX3397 solubility dmso 18 h. T-cell proliferation was determined using a TopCount Microplate Scintillation Counter (Packard Instruments). For intracellular cytokine staining, T cells from MLR assay were re-stimulated with 50 ng/mL PMA (Sigma), 1 μM ionomycin (Sigma) and treated with monensin (BioLegend) overnight. Monocytes and allogeneic T cells from three donors each were used. All paraffin-embedded tumour tissue samples and procedures were approved by the Centralised Institutional Review Board (CIRB), Singhealth, Singapore (Reference code: 2009/1001/B). Paraffin sections were stained with anti-CD68 (PG-M1, Novus Biologicals) and anti-CD3 (polyclonal, Dako), detected using DakoCytomation EnVision+ HRP System and peroxidase substrate AEC Kit (Vector Laboratories). Paraffin sections were stained with anti-IFN-γ (polyclonal, Abcam), anti-CD3 (F7.2.38, Dako) and anti-CD68 as above, detected using AlexaFluor488 donkey anti-rabbit, AlexaFluor546 donkey anti-mouse secondary antibodies, mounted with Prolong® anti-fade containing DAPI (Invitrogen). Images were

acquired with the TissueFAXS platform (TissueGnostics, Austria). For IHC, manual quantification find more of CD68+ and CD3+ cells in ten images (each ∼1200×500 μm) randomly taken from each tumour tissue sample was performed. Correlation of the two cell types was assessed using linear regression. For IF, quantification of staining was performed using the software TissueQuest (TissueGnostics) on five images (each ∼350×250 μm)

randomly Fludarabine concentration taken from each tumour tissue sample. Student’s t-tests were used: *p<0.05; **p<0.01; ***p<0.001; ns, not significant. All data plotted represent mean±standard deviations (SD). The authors thank NUH Blood Donation Center for supplying buffy coats; the staff Histology and Microarray Units (Biopolis Shared Facilities), Ms. Poon Lai Fong, Mr. Adrian Lai Tuck-Siong and Dr. Esther Koh for technical assistance; Dr. Shi Xianke (Carl Zeiss, Singapore) for the loan of TissueFAXS and TissueQuest platform; Dr. Lucy Robinson for scientific editing of the manuscript, Dr. Jean-Pierre Abastado and Dr. Subhra K. Biswas for critical reading of the manuscript; Dr Rotzschke’s Lab for SW620 and LS174T cell lines; and members of PK Lab for their input. This research is funded by the Biomedical Research Council, A*STAR, Singapore. Conflict of interest: The authors declare no financial or commercial conflict of interest. Detailed facts of importance to specialist readers are published as ”Supporting Information”.