Identification of two HLA-A*0201 immunogenic epitopes of lactate dehydrogenase C (LDHC): potential novel targets for cancer immunotherapy

Abstract

Lactate dehydrogenase C (LDHC) is an archetypical cancer testis antigen with limited expression in adult tissues and reexpression in tumors. This restricted expression pattern together with the important role of LDHC in cancer metabolism renders LDHC a potential target for immunotherapy. This study is the first to investigate the immunogenicity of LDHC using T cells from healthy individuals. LDHC-specific T cell responses were induced by in vitro stimulation with synthetic peptides, or by priming with autologous peptide-pulsed dendritic cells. We evaluated T cell activation by IFN-γ ELISpot and determined cytolytic activity of HLA-A*0201-restricted T cells in breast cancer cell co-cultures. In vitro T cell stimulation induced IFN-γ secretion in response to numerous LDHC-derived peptides. Analysis of HLA-A*0201 responses revealed a significant T cell activation after stimulation with peptide pools 2 (PP2) and 8 (PP8). The PP2-and PP8-specific T cells displayed cytolytic activity against breast cancer cells with endogenous LDHC expression within a HLA-A*0201 context. We identified peptides LDHC 41−55 and LDHC 288−303 from PP2 and PP8 to elicit a functional cellular immune response. More specifically, we found an increase in IFN-γ secretion by CD8 + T cells and cancer-cell-killing of HLA-A*0201/LDHC positive breast cancer cells by LDHC 41−55-and LDHC 288−303-induced T cells, albeit with a possible antigen recognition threshold. The majority of induced T cells displayed an effector memory phenotype. To conclude, our findings support the rationale to assess LDHC as a targetable cancer testis antigen for immunotherapy, and in particular the HLA-A*0201 restricted LDHC 41-55 and LDHC 288-303 peptides within LDHC.

Sperm proteins and cancer‐testis antigens are released by the seminiferous tubules in mice and men

“…Finally, we used Western blotting of human TIF as an independent, non-mass spectrometry-based, method to detect immunoreactive human LDHC, a sperm-specific protein, and CTA being considered as an immunotherapy target. 61 LDHC was detectable in TIF from men with intact spermatogenesis, but was significantly reduced in men with nonobstructive azoospermia due to spermatogenic disruption. LDHC in TIF was also significantly reduced in mice with seminiferous epithelial disruption.…”

“…LDHC is also a CTA and has been suggested to be a promising target for immunotherapy. 61 We also chose LDHC because it shows a higher relative abundance in both mouse and human TIF compared to other sperm-specific proteins and thus is more likely to be detectable by the less sensitive technique of Western blotting.…”

Identification of CTL Epitopes on Efflux Pumps of the ATP-Binding Cassette and the Major Facilitator Superfamily of Mycobacterium tuberculosis

“…On day 3, Fresh DC media (100 ng/mL IL-4 and 100 ng/mL GM-CSF) were replenished. On day 5 of the culture, 10 ng/mL lipopolysaccharide (LPS, Sigma, USA) was added for another two days to induce the maturation of DCs [ 33 ].…”

“…The CTL induction assay was performed in accordance with the protocols as previously described [ 32 , 33 ]. Briefly, DCs were pulsed with different peptides at a final concentration of 10 μ g/mL in the presence of 3 μ g/mL β 2-M for 24 h. Then, peptide-pulsed DCs (1 × 10 5 ) were cocultured with thawed autologous T cells (1 × 10 6 ) in 24-well plates in RPMI-1640 medium supplement with 10% FBS, human recombinant IL-2 (rhIL-2, 50 U/mL, 200-02, PeproTech, USA), and human recombinant IL-7 (rhIL-7, 10 ng/mL, 200-07, PeproTech, USA).…”

Lactate Metabolism and Immune Modulation in Breast Cancer: A Focused Review on Triple Negative Breast Tumors

“…Although the substrate preference of LDHA and LDHB differs, these observations indicate that substrate affinity and the extent of metabolic adaptation in tumors may vary depending on both tumor-specific intrinsic and extrinsic cues. The LDHC isoenzyme is an immunogenic germline-specific antigen that is re-expressed in a wide variety of cancer types (46,47). Particularly, high levels of circulating LDHC in serum and tumor-derived exosomes are negatively correlated with breast cancer prognosis (48).…”