Aref A.M.Hoa N.T.Ge L.Agrawal A.Dacosta-Iyer M.Lambrecht N.Ouyang Y.Cornforth A.N.Jadus M.R.Biological Science DepartmentModern Sciences and Arts UniversityCairoEgypt; Southern California Institute for Research and EducationVeterans Affairs Medical CenterLong BeachCAUnited States; Research Health Care GroupVeterans Affairs Medical CenterLong BeachCAUnited States; Department of MedicineDivision of Basic and Clinical ImmunologyUniversity of CaliforniaIrvineCAUnited States; Pathology and Laboratory Medicine DepartmentVeterans Affairs Medical Center Long BeachCAUnited States; Department of Pathology and Laboratory MedicineUniversity of CaliforniaIrvineCAUnited States; California Stem CellsIncCAUnited States; Chao Comprehensive Cancer CenterUniversity of CaliforniaIrvineCAUnited States2020-01-092020-01-09201411786930https://doi.org/10.2147/OTT.S61442PubMedIDhttps://t.ly/6xxlYScopusMSA Google ScholarBackground: Immunotherapy for human hepatocellular cancer (HCC) is slowly making progress towards treating these fatal cancers. The identification of new antigens can improve this approach. We describe a possible new antigen, hepatocellular carcinoma-associated antigen-519/targeting protein for Xklp-2 (HCA519/TPX2), for HCC that might be beneficial for T-cell specific HCC immunotherapy. Methods: HCC was studied for the expression for 15 tumor-associated antigens considered useful for immunotherapy within three HCC cell lines (HepG2, Hep3B, and PLC/PRF/5), lymphocytes, non-cancerous livers, and clinical HCC. The expression of tumor antigenic precursor proteins (TAPPs) messenger RNA was first screened by reverse transcriptase quantitative real-time polymerase chain reaction. Results: Four antigens (alpha fetoprotein, aspartyl/asparaginyl ?-hydroxylase, glypican-3 and HCA519/TPX2) proved to be the best expressed TAPPs within the HCC specimens by molecular analyses. HCA519/TPX2 was detected by intracellular cell flow cytometry within HCC cell lines by using a specific antibody towards this TAPP. This antibody also detected the protein within primary HCCs. We synthesized two HCA519/TPX2 peptides (HCA519464-472 and HCA519351-359) which can bind to human leukocyte antigen (HLA)-A*0201. Dendritic cells pulsed with these peptides stimulated cytolytic T lymphocytes (CTLs). These killer T-cells lysed HLA-Az.ast;0201+ T2 cells exogenously loaded with the correct specific peptide. The CTLs killed HepG2 (HLA-A2+ and HCA519+), but not the Hep3B and PLC/PRF/5 cell lines, which are HCA519+ but HLA-A2-negative. In silico analysis reveals that HCA519/TPX2 has the inherent ability to bind to a very wide variety of HLA antigens. Conclusion: HCA519/TPX2 is a viable immunotarget that should be further investigated within HCC patients. � 2014 Aref et al. This work is published by Dove Medical Press Limited.EnglishCytolytic T-cellsHCA519/TPX2HLA-A2Tumor immunityalpha fetoproteinaspartyl asparaginyl beta hydroxylaseglypican 3HLA A antigenmessenger RNAoxygenaseprotein TPX2tumor antigenunclassified drugantigen bindingantigen expressionarticlecancer immunotherapycarcinoma cell lineclinical articlecomputer modelcontrolled studycytotoxic T lymphocyteflow cytometryhumanhuman cellliver cell carcinomaprotein expressionprotein synthesisreal time polymerase chain reactionreverse transcription polymerase chain reactionArticlehttps://doi.org/10.2147/OTT.S61442PubMedID