The present invention discloses an improved method for expansion and activation of tumor-reactive lymphocytes, in particular CD4+ helper and/or CD8+ T-lymphocytes, which may be used for treating and/or preventing cancer. The method provides high numbers of tumor-reactive T-lymphocytes within a short time span and the possibility of directing development of tumor-reactive CD4+ helper and/or CD8+ T-lymphocytes towards specific subpopulations. The method comprises a first phase of stimulating tumor-reactive CD4+ T helper and/or CD8+ T-lymphocytes with tumor-derived antigen together with at least one substance having agonistic activity towards the IL-2 receptor to promote survival of tumor-reactive CD4+ T helper and/or CD8+ T-lymphocytes and a second phase of activating and promoting growth of tumor-reactive CD4+ T helper and/or CD8+ T-lymphocytes, wherein the second phase is initiated when the CD25 cell surface marker (or IL-2R marker) is down-regulated on CD4+ T helper and/or CD8+ T-lymphocytes.
