Pharmacological blockade of PI3K δ and VIP signaling results in increased cell yield, preservation of CD27⁺CD28⁺cells and enhanced IL-2 production during ex vivo T-cell expansion. T cells from healthy donors and DLBCL patients were expanded in vitro in the presence or absence of idelalisib and/or VIPhyb for 14 days. Cells were counted on days 7 and 14 of expansion and phenotyped by flow cytometry for surface markers or cytokine production on day 14. (A) Expansion profiles of healthy controls under the indicated culture conditions. (B) Waterfall plot showing the expansion of DLBCL patient samples relative to DMSO controls. The numbers below the bars indicate specific patient samples. (C) Representative flow plots showing the expression of CD27 and CD28 on the total T-cell population. (D) Quantification of double-positive and double-negative T cells from 10 lymphoma patients. (E) Representative flow plots of IL-2 and IFN-γ production by human CD4 and CD8 T cells after 14 days of expansion under the indicated culture conditions. (F) Quantitation of total frequencies of cells producing the indicated cytokines as well as single, double, and triple cytokine-producing T cells (n = 6 healthy donors). *P < .05, **P < .01, ***P < .001. TNF, tumor necrosis factor.