Peptides spanning the junctional region of both the abl/bcr and the bcr/abl fusion proteins bind common HLA class I molecules

Abstract

The Philadelphia (Ph) chromosome, resulting from the t(9;22) translocation, is characteristic of chronic myeloid leukemia (CML). As a result of this translocation, two novel chimeric genes are generated and the bcr/abl and abl/bcr fusion proteins expressed. The bcr/abl fusion mRNA is present in all CML patients, whereas the reciprocal abl/bcr fusion mRNA is detectable in about 80% of the Ph + CML patients. These fusion proteins may undergo enzymatic degradation in the cytosol and give rise to MHC class I restricted peptide epitopes originating from the junctional regions of the translocation products, which thus may serve as novel tumor specific antigens. Previously, other groups have tested peptides corresponding to the junctional region of the bcr/abl protein for their binding capacity to HLA class I molecules and have identified a few candidate epitopes. Peptides originating from the abl/bcr fusion protein have on the other hand so far been neglected, for no apparent reason. We have now extended these studies to include also the reciprocal abl/bcr translocation product by testing a large panel of synthetic peptides corresponding to the junctional regions of both the abl/bcr and the bcr/abl fusion proteins for their ability to stabilize HLA class I molecules. We find that the abl/bcr translocation product may be an even more important source of CML specific peptide antigens and together the junctional sequences of both these proteins contain peptide sequences which bind efficiently to a number of HLA molecules (HLA-A1, -A2, -A3, -A11, -B7, -B27, -B35) and thus may serve as candidate CML specific tumor antigens. Leukemia (2000) 14, 419-426.

Identification of Novel Survivin-Derived CTL Epitopes with Different HLA-A-Restriction Profiles

“…The ELISPOT assay was used to quantify peptide epitope-specific interferon-γ releasing effector cells as described previously. 30 Briefly, nitrocellulose bottomed 96-well plates (MultiScreen MAIP N45, Millipore, Hedehusene, Denmark) were coated with anti-IFN-γ antibody (1-D1K, Mabtech, Nacka, Sweden). The wells were washed, blocked by X-vivo medium, and the cells were added in duplicates at different cell concentrations.…”

BCR-ABL fusion regions as a source of multiple leukemia-specific CD8+ T-cell epitopes

“…28 Peripheral blood mononuclear cells of an HLA-B61-positive healthy donor (for inductions against b2a2 12-21 and e1a2 [13][14][15][16][17][18][19][20][21] ) and an HLA-A68-positive (for induction against b2a2 [8][9][10][11][12][13][14][15][16][17][18] ) healthy donor were used for the generation of antigen presenting cells and autologous CD8 þ T cells. Peptide specificity of bulk CTL cultures was tested at day 28 in a standard 51 Cr cytotoxicity assay.…”

“…Peptide specificity of bulk CTL cultures was tested at day 28 in a standard 51 Cr cytotoxicity assay. The highly peptidespecific T-cell culture against e1a2 [13][14][15][16][17][18][19][20][21] (AEALQRPVA) was cloned by limiting dilution at day 29. Recognition of tumor cells by peptide-specific CTL clones was tested in an interferon-g enzyme-linked immunosorbent assay (ELISA): 20.000 CTL/well were coincubated with 20 000 tumor cells/well in a 96-well plate and supernatants were harvested after 14 h.…”

“…Binding of fusion peptides to HLA-A2, by far the most prevalent molecule, is subject of conflicting data. Most studies 14,15,[17][18][19] did not find binding of fusion peptides in HLA-A2, however, two others reported significant binding 16,20 (summarized in Table 2). …”

“…Therefore, BCR-ABL fusion regions have been scrutinized as targets for CTL-mediated immunotherapy. Fusion peptides from the b3a2 and b2a2 regions were found to bind to the human lymphocyte antigen (HLA)-A3/A11, 14,15 HLA-B7, 16 HLA-B8, 14,17 HLA-B27, 16 HLA-B35 16 and HLA-B44 17 HLA class I molecules. Binding of fusion peptides to HLA-A2, by far the most prevalent molecule, is subject of conflicting data.…”