Leukocytes were extracted from tumors of GPR55-/- and wild-type (WT) mice and analyzed by flow cytometry. (A) Viable cells were gated from an FSC/SSC plot and CD11b+ cells were further analyzed for their Ly6C/Ly6G expression. (B) A subpopulation of CD11b+ cells, i.e. Ly6C+Ly6G- cells was significantly reduced in tumors of GPR55-/- mice. (C-E) Following a leukocyte gate (CD45+), cells were further gated for CD3. (C) Tumors of GPR55-/- mice showed a strong increase of CD3+ leukocytes. (D, E) CD3+ cells were further analyzed for their CD4 and CD8 expression. CD4+ cells (Q1) and CD8+ cells (Q3) were more abundant in tumors of GPR55-/- mice than in tumors of wild-type mice. Each dot represents the leukocytes extracted from tumors of one mouse, and bars are the means. * P < .05, *** P < .001, n=9-12