[Function analysis of the family-specific CTL induced by peptides derived from IgHV gene framework region of B-cell malignance].
OBJECTIVE
To identify immune epitopes existed in the framework region (FR) of the IgHV protein of B-cell malignance, and explore the use of these FR-derived peptides to induce the family specific immune response in vitro, in order to explore the possibility of a new IgHV gene family-specific immunotherapy for B-cell malignance.


METHODS
Bioinformatics was used for predicting T cell epitopes in IgHV protein. Peptides of interest were synthesized in vitro. T2 cell binding assay was performed to determine the binding ability of the peptides to HLA-A*0201 molecules. Peptide/HLA tetramer staining was used to detect the number of peptide-specific cytotoxic T lymphocytes (CTLs). Cytotoxicity assay was used to determine killing activity.


RESULTS
Twelve peptides that were common to seven IgHV gene subfamilies were identified, and 10 (83%) of them were located in the FR of IgHV protein. The synthesized peptides up-regulated HLA*0201 molecules fluorescence intensity on cell surfaces of T2. By using an antigen-specific T-cell expansion system in vitro, the peripheral blood mononuclear cells (PBMNC) from a healthy HLA-A0201 donor were stimulated weekly by autologous PBMNC loaded with the peptide as antigen presenting cells (APC), and the peptide-specific CTLs were demonstrated to be generated successfully in the healthy donors. The frequency of CD8 and peptide/HLA tetramer double positive cells in the gated lymphocyte population was 0.38% before stimulation and increased to 49.38 % after four times stimulation. Cytotoxicity assay indicated that these CTLs were capable of killing the HLA-A*0201, IgHV1 (+) lymphoma cells. Furthermore, the generated CTL could not kill the target cell loaded with the IgHV3 peptide, indicating that the cytotoxicity is family-specific.


CONCLUSIONS
Peptides derived from the IgHV protein FR can successfully induce the generation of peptide-specific CTLs in vitro. These CTLs are capable of killing the lymphoma cell belonged to the same subfamily in a peptide-specific and MHC-restricted way. These findings could potentially form the basis of broadening application of immunoglobulin-directed immunotherapy in B-cell malignancies.
Guo
Xiao-Ling
XL
Peking University, First Hospital, Beijing, China.
Zhu
Ping
P
Liu
Ying
Y
Liu
Jing
J
Zhu
Xia
X
D002478:Cells, Cultured; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000276:immunology*; D007135:Immunoglobulin Variable Region / Q000276:immunology*; D016393:Lymphoma, B-Cell / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D018985:Epitopes, B-Lymphocyte; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region