Work

Characterization of the tumor-specific activity of WT1 specific T cells generated in vitro from normal individuals by sensitization with WT1-peptide loaded autologous EBV transformed B cells

Year: 2004

Type: article

Abstract: The Wilms’ tumor protein WT1 is over-expressed in most acute and chronic leukemias. Isolated T-cell clones have been reported to recognize WT1 peptides binding by HLA-A0201 and HLA-A2402 and lyse WT1+ leukemic lines. To test WT1 peptide immunogenicity in normal individuals, we sensitized T-cells from 9 HLA-A0201+ and 4 HLA-A2402+ donors with autologous EBV transformed B cells (EBV-BLCL) or cytokine-activated monocytes (CAM), loaded with HLA-A0201-binding WT1 peptides RMFPNAPYL or SLGEQQYSV or the HLA- A2402- binding WT1 peptide RVPGVAPTL. WT1-peptide specific cytotoxic and interferon-gamma producing T-cells were generated from each donor. T-cells sensitized with peptide-loaded EBV-BLCL generated higher numbers of WT1 specific T-cells than peptide loaded CAM. The frequencies of WT1 peptide-specific T-cells measured by binding to peptide-HLA tetramers were similar to those generated against individual immunogenic HLA-A0201 binding EBV peptides. These T-cells specifically lysed WT1+ leukemias (n = 16) and solid tumors (n = 12) in an HLA-restricted manner, but neither lysed autologous or HLA-sharing normal CD34+ hematopoietic progenitor cells (n = 12) nor affected their yield of CFU-GM, BFU-C or CFU-MIX. Following adoptive transfer into SCID mice bearing subcutaneous xenografts of WT1+ and WT1−, HLA-A0201+ leukemias, WT1-peptide-specific T-cells preferentially accumulated in and induce regressions only of WT1+ leukemias . The long-term repeated in vivo scintigraphic imaging of such T cells, transduced to express an HSV-TK/GFP fusion gene, following intravenous infusions of the HSV-TK substrate [131I]-FIAU demonstrated progressive accumulation of the T cells over a period of 8 days in tumors, expressing targeted antigen and the HLA restricting allele. These studies demonstrate that T cells specific to the self antigen WT1 can be regularly generated from normal individuals and that these cells exhibit significant anti-tumor activity both in vitro and in vivo. Such cells may prove useful for adoptive therapy of leukemias in man. The Wilms’ tumor protein WT1 is over-expressed in most acute and chronic leukemias. Isolated T-cell clones have been reported to recognize WT1 peptides binding by HLA-A0201 and HLA-A2402 and lyse WT1+ leukemic lines. To test WT1 peptide immunogenicity in normal individuals, we sensitized T-cells from 9 HLA-A0201+ and 4 HLA-A2402+ donors with autologous EBV transformed B cells (EBV-BLCL) or cytokine-activated monocytes (CAM), loaded with HLA-A0201-binding WT1 peptides RMFPNAPYL or SLGEQQYSV or the HLA- A2402- binding WT1 peptide RVPGVAPTL. WT1-peptide specific cytotoxic and interferon-gamma producing T-cells were generated from each donor. T-cells sensitized with peptide-loaded EBV-BLCL generated higher numbers of WT1 specific T-cells than peptide loaded CAM. The frequencies of WT1 peptide-specific T-cells measured by binding to peptide-HLA tetramers were similar to those generated against individual immunogenic HLA-A0201 binding EBV peptides. These T-cells specifically lysed WT1+ leukemias (n = 16) and solid tumors (n = 12) in an HLA-restricted manner, but neither lysed autologous or HLA-sharing normal CD34+ hematopoietic progenitor cells (n = 12) nor affected their yield of CFU-GM, BFU-C or CFU-MIX. Following adoptive transfer into SCID mice bearing subcutaneous xenografts of WT1+ and WT1−, HLA-A0201+ leukemias, WT1-peptide-specific T-cells preferentially accumulated in and induce regressions only of WT1+ leukemias . The long-term repeated in vivo scintigraphic imaging of such T cells, transduced to express an HSV-TK/GFP fusion gene, following intravenous infusions of the HSV-TK substrate [131I]-FIAU demonstrated progressive accumulation of the T cells over a period of 8 days in tumors, expressing targeted antigen and the HLA restricting allele. These studies demonstrate that T cells specific to the self antigen WT1 can be regularly generated from normal individuals and that these cells exhibit significant anti-tumor activity both in vitro and in vivo. Such cells may prove useful for adoptive therapy of leukemias in man.

Source: Transplantation and Cellular Therapy

DOI: 10.1016/j.bbmt.2003.12.068