Expansion of interferon-gamma-producing multifunctional CD4+ T-cells and dysfunctional CD8+ T-cells by glypican-3 peptide library in hepatocellular carcinoma patients

Abstract

Glypican-3 is a promising target for immunotherapy for hepatocellular carcinoma, but limited data exist regarding its immunogenicity in patients with diverse HLA types, immunogenicity for CD4+ T-cells, and the impact of inhibitory co-stimulation on glypican-3-specific T-cells. Using a 15mer overlapping peptide library for glypican-3, PBMC from patients with HCC were assessed ex vivo and after short-term in vitro expansion for tumor antigen-specific T-cell responses with and without blockade of PD-1/PD-L1 and CTLA-4 signaling. Glypican-3-specific T-cells were undetectable ex vivo, but primarily IFNγ+ TNFα+ CD4+ T-cells expanded with short-term in vitro stimulation in 10/19 (52%) patients. Glypican-3-specific CD8+ T-cells predominantly produced TNFα, but did not secrete IFNγ nor degranulate. CTLA-4 and PD-1 blockade minimally impacted the cytokine secretion and proliferation of glypican-3-specific T-cells. These data suggest that CD8+ T-cell-directed tumor vaccines in HCC may have limited potential for efficacy unless optimal co-stimulation conditions can be identified but CD4+-directed vaccines merit consideration.

Monocyte-derived dendritic cells from cirrhotic patients retain similar capacity for maturation/activation and antigen presentation as those from healthy subjects

“…However, there are some data that suggest that DC function in hepatocellular carcinoma may be impaired [16]. In previous work, our laboratory showed that tumor antigen-specific CD8+ T-cells generated using 15mer peptide stimulation in cirrhotic patients with HCC were dysfunctional [17]. Similar findings have subsequently been reproduced by other groups [18].…”

“…Antigen-specific T-cell IFNγ responses were examined after in vitro expansion in cytokine Elispot assay as previously described [17]. 5 × 10 4 antigen-expanded T-cells/well were restimulated with each peptide pool (1 μg/ml) in triplicates with positive (PHA) and negative (media) controls × 24 h in IFNγ Elispot plates.…”

“…In our previous work, we identified that CD8+ T-cells from cirrhotic patients who had not yet developed HCC appeared to harbor a small population of multifunctional tumor antigen-specific CD8+ T-cells [17]. We therefore hypothesized that in the presence of optimized antigen-presenting cells that we would be able to expand multifunctional tumor antigen-specific T-cells with potential tumor preventing capacity in cirrhotic individuals.…”

Phase I Trial of a Glypican-3–Derived Peptide Vaccine for Advanced Hepatocellular Carcinoma: Immunologic Evidence and Potential for Improving Overall Survival

“…In progressive HCC, the induction of CTL may be suppressed by regulatory T cells or immunosuppressive cytokines (33). It has been reported that GPC3-specific CTLs become exhausted in HCC, and that this exhausted state cannot be reversed by blocking the CTLA-4 and PD-1 inhibitory costimulation pathways (34). Further studies will be necessary to increase the clinical efficacy of immunotherapy for advanced HCC.…”

Immunotherapy of hepatocellular carcinoma

“…Glypican-3 (GPC3), a cell surface heparin sulfate proteoglycan, is expressed by 84% of HCC and has been shown to be immunogenic in murine models and human cell culture 46 . Because the frequency of GPC3-specific T cells is low in the peripheral blood of HCC patients, optimized costimulatory conditions may be required for ex vivo expansion of these cells 47 . NY-ESO-1 is an additional cancer/testes antigen expressed in HCC.…”