Submitted April 17, 2006
Accepted June 3, 2006
Identification of an immunogenic CD8+ T cell epitope derived from 
-globin, a putative tumor-associated antigen for juvenile myelomonocytic leukemia
Naoto Hirano*, Marcus Butler, Zhinan Xia, Alla Berezovskaya, Andrew P Murray, Sascha Ansen, Seiji Kojima, and Lee M Nadler
Department of Medical Oncology, Dana-Farber Cancer Institute; Brigham and Women's Hospital, Boston
Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA,USA
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
Department of Pediatrics, Nagoya University, Nagoya, Japan
* Corresponding author; email: naoto_hirano{at}dfci.harvard.edu.
Juvenile myelomonocytic leukemia (JMML) is a rare clonal myeloproliferative disorder. Although allogeneic stem cell transplantation can induce long-term remissions, relapse rates remain high and innovative approaches are needed. Since donor lymphocyte infusions have clinical activity in JMML, T cell mediated immunotherapy could provide a nonredundant treatment approach to compliment current therapies. 
-Globin, an oncofetal protein overexpressed by clonogenic JMML cells, may serve as a target of an anti-tumor immune response. We predicted 5 -globin derived peptides as potential HLA-A2 restricted CTL epitopes and showed that 4 (g031, g071, g105, and g106) bind A2 molecules in vitro. Using an artificial antigen presenting cell (aAPC) that can process both the N- and C-termini of endogenously expressed proteins, we biochemically confirmed that g105 is naturally processed and presented by cell surface A2. Furthermore, g105 specific CD8+ CTL generated from A2 positive healthy donors were able to specifically cytolyze -globin+, but not -globin-, JMML cells in an A2 restricted manner. These results suggest that this aAPC-based approach enables the biochemical identification of CD8+ T cell epitopes that are processed and presented by intact cells and that CTL immunotherapy of JMML could be directed against the -globin derived epitope g105.
