Analysis of Spontaneous Tumor-Specific CD4 T-cell Immunity in Lung Cancer Using Promiscuous HLA-DR Telomerase-Derived Epitopes: Potential Synergistic Effect with Chemotherapy Response

Abstract

Purpose: To investigate the presence and impact of spontaneous telomerase-specific CD4 T-cell responses in cancer patients.Experimental Design: A multistep approach was used to design novel pan-HLA-DR-restricted peptides from telomerase. T-cell clones isolated from cancer patients were used to characterize the polarization of telomerase-specific CD4 response. The presence of spontaneous CD4 T-cell response against telomerase was monitored in 84 metastatic non-small cell lung cancer (NSCLC) patients before first-line chemotherapy (CT) using IFN-g ELISPOT assay. Then we analyzed the impact of the pretherapeutic telomerase-specific CD4 T immunity on clinical outcome in patients according to their respective response to CT.Results: We described four novel telomerase-derived CD4 epitopes referred as universal cancer peptides (UCP) that effectively bind to most commonly found human MHC class II alleles. UCP-specific CD4 T-cell repertoire is present in human and UCP-specific CD4 T-cell clones generated from cancer patients exhibited high avidity and are Th1 polarized. Significant frequency (38%) of naturally occurring UCP-specific T-cell responses were detected before CT in advanced NSCLC but not in healthy volunteers. This response was shown to significantly increase overall survival (OS) of patients responding to CT (Median OS: 53 vs. 40 weeks, P ¼ 0.034).Conclusions: These results show for the first time a potential synergistic effect of telomerase-specific CD4 Tcell response with CT response in NSCLC and underline the potential role of tumor-specific CD4 T-cell response on the efficiency of conventional anticancer therapy.

Universal Cancer Peptide-Based Therapeutic Vaccine Breaks Tolerance against Telomerase and Eradicates Established Tumor

“…The 4 peptides derived from TERT called UCPs: UCP1 (TERT [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] : PAAFRALVAQCLVCV), UCP2 (TERT 578-592 : KSVWSKLQSIGIRQH), UCP3 (TERT 916-930 : GTAFVQM-PAHGLFPW), and UCP4 (TERT 1041-1055 : SLCYSILKA-KNAGMS) have been described recently (19). The modified (first amino acid substitution with a tyrosine) HLA-A2-restricted pY988 (YLQVNSLQTV) and pY572 (YLFFYRKSV) peptides derived from TERT have been described elsewhere as high-affinity forms of their cryptic counterparts (23,24).…”

“…Ficoll-isolated lymphocytes were analyzed by 3 H-thymidine incorporation as described previously (25). After a short in vitro stimulation of lymphocytes with UCPs as previously reported (19), UCP-specific immune responses were analyzed by human ELISPOT assay (GenProbe). Concomitantly, cytokines production was measured after a 15-hour culture with or without UCPs using DIAplex Human Th1/Th2 kit (GenProbe) according to the manufacturer's instructions.…”

“…19). TERT expression has been detected in all studied cancer forms including stem cell-like tumor cells (20,21).…”

“…Thus TERT has emerged as a clinically relevant tumor antigen for cancer vaccines (22). These TERT-derived UCPs effectively bind to the most commonly found HLA-DR alleles (19).…”

CD20 alternative splicing isoform generates immunogenic CD4 helper T epitopes

“…14 Functional analyses of specific CD4 T-cell clones were done by using intracellular IFN-g staining, IFN-g ELISA (Diaclone) and Human Ten-plex cytokines assay (Human Th1/Th2/Inflammation Diaplex; Diaclone). Th0 cells were isolated using the na€ ıve CD4 T cell isolation kit II (Miltenyi Biotec, Paris, France).…”