Objective: To induce anti-B-cell acute lymphoblastic leukemia (B-ALL) cytotoxic T lymphocyte response against immunoglobulin heavy chain frame-derived nonapeptide.
Methods: The peptide, QLVQSGAEV, containing IgHV1 frame region 3rd-11th amino acids (IgHV1(3-11)), was synthesized. IgHV1(3-11)-T2 binding tests were performed. HLA-A * 0201-positive normal peripheral blood mononuclear cells (PBMNC) were stimulated by IgHV1(3-11)-loaded antigen presenting cells three times at weekly intervals. HLA-A * 0201/IgHV1(3-11) tetramers were used to detect the proliferation of IgHV1(3-11)-specific CD8(+) T cells in the culture. Seven IgHV gene families of B-ALL patients were respectively amplified by PCR and the PCR products were sequenced to select IgHV1 and IgHV3 family monoallelic functional rearrangements. Among them, HLA-A * 0201 positive individuals were subsequently identified. Cytotoxicity of IgHV1(3-11)-specific CD8(+) T cells against HLA-A * 0201-positive IgHV1/IgHV3 family B-ALL cells was measured by MTT assay.
Results: The synthesized IgHV1(3-11) up-regulated HLA-A * 0201 expression on T2 cell surface by 1.63-folds. The percentage of IgHV1(3-11)-specific CD8(+) T cells in HLA-A * 0201-positive normal PBMNC was increased from 1.64% after second stimulation to 82.57% after third stimulation. At effector: target ratio of 20:1, the killing rate of IgHV1(3-11)-specific CD8(+) T cells against IgHV1 family B-ALL cells was 18.24%, being 1.8-folds as that against IgHV3 family B-ALL cells (P = 0.01).
Conclusion: Cytolytic T lymphocytes generated in vitro against immunoglobulin heavy chain frame-derived nonapeptides can kill B-ALL cells expressing these peptides.