IMPS-17: BRANCHED-MULTIPEPTIDE IMMUNOTHERAPY FOR GLIOBLASTOMA USING HLA-A*0201-RESTRICTED CYTOTOXIC T-LYMPHOCYTE EPITOPE FROM BIRC5, CD99 AND ERBB2

BACKGROUND: Branched-multipeptide has the increased molecular weight of the peptide which can elevate stable immunogenicity in the body. We identified and synthesized BIRC5, CD99 and ERBB2 peptides and their corresponding branched-multipeptide for HLA-A*0201 molecules. We investigated the possibility of immunotherapy for glioblastoma using cytotoxic T lymphocytes (CTLs) generated by branched-multipeptides pulsed dendritic cells (DCs). MATERIALS AND METHODS: We selected three peptides (BIRC5, CD99 and ERBB2), on the basis of their binding affinity, as determined by a peptide-T2 binding assay and their corresponding branched-multipeptide was synthesized using mini-polyethylene glycol (mini-PEGs) spacer. The function of DCs pulsed with multipeptide- cocktail was compared with DCs pulsed with branched-multipeptide by immunephenotype and cytokine secretion. We measured the functional activity for CTLs by using IFN-γ-enzyme linked immune absorbent spot (ELISPOT) assay. RESULTS: The stability of branched-multipeptide-T2 cells binding was relatively well maintained up to 24 hours compared to multipeptide cocktail. Based on FACS analysis which compared the phenotypes of multipeptide-cocktail and branched-multipeptide pulsed DCs, both DCs exhibited high expression of CD80, CD83 and CD86, which meant that both DCs resulted in efficient generation of DCs without altering the phenotype of the mature DCs. The both multipeptides pulsed DCs showed similarly increased IL-12p70, IL-12p40and IL-10 production. The CTLs that were stimulated by both multipeptides pulsed DCs displayed a greater number of IFN-γ-secreting cells against T2 cells loaded with both multipeptides and glioblastoma cell lines compared to those stimulated by un-pulsed DCs. CONCLUSION: Branched-multipeptide of BIRC5, CD99 and ERBB2 showed the stable binding with T cells and similar cytotoxic activity to target cells compared with multipeptide-cocktail. Branched-multipeptide can be the candidate of useful immunotherapeutic modalities for glioblastoma. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2014R1A1A1004469).