A U.S. Patent for “Methods of Making T Cell Compositions” was awarded to Bluebird Bio on November 19th, 2019. The present invention is a method for manufacturing T cells comprising: a) activating a population of T cells and stimulating the population of T cells to proliferate; b) transducing the T cells with a viral vector comprising a polynucleotide encoding an engineered T cell receptor (TCR) or a chimeric antigen receptor (CAR); and c) culturing the transduced T cells to proliferate; wherein steps a)-c) are performed in the presence of a phosphatidylinositol-3 kinase (PI3K) inhibitor, and wherein T cell differentiation is decreased. Learn More