Genetic engineering of murine CD8+ and CD4+ T cells for pre-clinical adoptive immunotherapy studies

T-cell-receptor (TCR) gene therapy enables for the rapid creation of antigen-specific T cells from mice of any strain and represents a valuable tool for pre-clinical immunotherapy studies. Here, we describe the superiority of gamma-retroviral vectors compared to lentiviral vectors for transduction of murine T cells and surprisingly illustrate robust gene-transfer into phenotypically naïve/memory-stem cell (CD62L hi /CD44 low ) and central memory (CD62L hi /CD44 hi ) CD8 + T cells using murine-stem-cell-based gamma-retroviral vectors (MSGV1). We created MSGV1 vectors for a MHC-class I restricted T-cell receptor (TCR) specific for the melanocyte-differentiation antigen, gp100 (MSGV1-pmel-1), and a MHC-class II restricted TCR specific for tyrosinase-related-protein-1 (MSGV1-TRP-1), and found that robust gene expression required codon optimization of TCR sequences for the pmel-1 TCR. To test for functionality, we adoptively transferred TCR-engineered T cells into mice bearing B16 melanomas and observed delayed growth of established tumors with pmel-1TCR engineered CD8 + T cells and significant tumor regression with TRP-1 TCR transduced CD4 + T cells. We simultaneously created lentiviral vectors encoding the pmel-1TCR, but found that these vectors mediated low TCR expression in murine T cells, but robust gene expression in other murine and human cell lines. These results indicate that preclinical murine models of adoptive immunotherapies are more practical using gamma-retroviral rather than lentiviral vectors.