Identification of HLA-A2-restricted CTL epitope encoded by the MAGE-n gene of human hepatocellular carcinoma

Cytotoxic T-lymphocyte elicited therapeutic vaccine candidate targeting cancer against MAGE-A11 carcinogenic protein

Immunotherapy is a breakthrough approach for cancer treatment and prevention. By exploiting the fact that cancer cells have overexpression of tumor antigens responsible for its growth and progression, which can be identified and removed by boosting the immune system. In silico techniques have provided efficient ways for developing preventive measures to ward off cancer. Herein, we have designed a potent cytotoxic T-lymphocyte epitope to elicit a desirable immune response against carcinogenic melanoma-associated antigen-A11. Potent epitope was predicted using reliable algorithms and characterized by advanced computational avenue CABS molecular dynamics simulation, for full flexible binding with HLA-A*0201 and androgen receptor to large-scale rearrangements of the complex system. Results showed the potent immunogenic construct (KIIDLVHLL), from top epitopes using five algorithms. Molecular docking analyses showed the strong binding of epitope with HLA-A*0201 and androgen receptor with docking score of -780.6 and -641.06 kcal/mol, respectively. Molecular dynamics simulation analysis revealed strong binding of lead epitope with androgen receptor by involvement of 127 elements through atomic-model study. Full flexibility study showed stable binding of epitope with an average root mean square deviation (RMSD) 2.21 Å and maximum RMSD value of 6.48 Å in optimal cluster density area. The epitope also showed remarkable results with radius of gyration 23.0777 Å, world population coverage of 39.08% by immune epitope database, and transporter associated with antigen processing (TAP) affinity IC50 value of 2039.65 nm. Moreover, in silico cloning approach confirmed the expression and translation capacity of the construct within a suitable expression vector. The present study paves way for a potential immunogenic construct for prevention of cancer.

Effects of a Single Escape Mutation on T Cell and HIV-1 Co-adaptation

The mechanistic basis for the progressive accumulation of Y(135)F Nef mutant viruses in the HIV-1-infected population remains poorly understood. Y(135)F viruses carry the 2F mutation within RW8 and RF10, which are two HLA-A(∗)24:02-restricted superimposed Nef epitopes recognized by distinct and adaptable CD8(+) T cell responses. We combined comprehensive analysis of the T cell receptor repertoire and cross-reactive potential of wild-type or 2F RW8- and RF10-specific CD8(+) T cells with peptide-MHC complex stability and crystal structure studies. We find that, by affecting direct and water-mediated hydrogen bond networks within the peptide-MHC complex, the 2F mutation reduces both TCR and HLA binding. This suggests an advantage underlying the evolution of the 2F variant with decreased CD8(+) T cell efficacy. Our study provides a refined understanding of HIV-1 and CD8(+) T cell co-adaptation at the population level.

Information technologies for vaccine research

Vaccinology is a combinatorial science which studies the diversity of pathogens and the human immune system, and formulations that can modulate immune responses and prevent or cure disease. Huge amounts of data are produced by genomics and proteomics projects and large-scale screening of pathogen-host and antigen-host interactions. Current developments in computational vaccinology mainly support the analysis of antigen processing and presentation and the characterization of targets of immune response. Future development will also include systemic models of vaccine responses. Immunomics, the large-scale screening of immune processes which includes powerful immunoinformatic tools, offers great promise for future translation of basic immunology research advances into successful vaccines.

Prediction and analysis of HLA-A2/A24-restricted cytotoxic T-lymphocyte epitopes of the tumor antigen MAGE-n using the artificial neural networks method on NetCTL1.2 Server

Cancer immunotherapy has become one of the most important therapeutic approaches to cancer in the past two decades. Tumor antigen-derived peptides have been widely used to elicit tumor-specific cytotoxic T lymphocytes (CTLs). Antigen-specific CTLs induced by MAGE-derived peptides have proven to be highly efficacious in the prevention and treatment of various types of tumor. MAGE-n is a new member of the MAGE gene family and has been shown to be closely associated with hepatocellular carcinoma. It is highly homologous to the MAGE-A gene subfamily, particularly to MAGE-3 (93%). MAGE-n-derived peptide QLVFGIEVV is a novel HLA-A2.1-restricted CTL epitope that induces MAGE-n-specific CTLs in vitro. Identification of these CTL epitopes may lead to clinical applications of these peptides as cancer vaccines for patients with MAGE-n(+)/HLA-A2(+) tumors. In the present study, HLA-A/A24-restricted CTL epitopes of antigen MAGE-n were predicted using the NetCTL1.2 Server on the web, COMB >0.85. The results showed that the NetCTL1.2 Server prediction method improved prediction efficacy and accuracy. Additionally, 8 HLA-A2- and 9 HLA-A24-restricted CTL epitope candidates (nonamers) derived from the tumor antigen MAGE-n were predicted. These nonamers, following identification via experimentation, may contribute to the development of potential antigen peptide tumor vaccines.

Clinical and immunologic responses of HLA-A3+ breast cancer patients vaccinated with the HER2/neu-derived peptide vaccine, E75, in a phase I/II clinical trial

BACKGROUND

We have treated disease-free breast cancer patients with an HER2/neu-derived peptide, E75, as an adjuvant vaccine. E75 was originally described as HLA-A2-restricted and has been previously tested in this population. Based on computer modeling, E75 is predicted to bind to HLA-A3, and preclinical data support this. We conducted a clinical trial of E75 in HLA-A3(+), A2(-) (A3) patients.

STUDY DESIGN

Disease-free breast cancer patients were enrolled after standard therapy in phase I/II trials. A3 patients were enrolled in parallel with A2 patients and vaccinated with E75 and granulocyte-macrophage colony-stimulating factor immunoadjuvant. A2(-), A3(-) patients were followed as controls. Toxicities were graded. Immunologic responses were assessed by delayed-type hypersensitivity reactions and E75-specific interferon-gamma enzyme-linked immunosorbent spot assay. Clinical recurrences were documented.

RESULTS

Thirteen A3 patients completed the vaccine schedule. Clinicopathologic features were similar between A3, A2, and control patients, except for more HER2/neu-overexpressing tumors in the A2 group and more estrogen-receptor/progesterone-receptor-negative tumors in A2 and A3 groups. Toxicity profiles and postvaccination delayed-type hypersensitivity were similar in A3 and A2 patients. Enzyme-linked immunosorbent spot assay results varied, but A3 patients' median spots increased pre- to postvaccination (p = 0.2). Recurrences were lower in the A3 group (7.7%) at 30-month median follow-up compared with published recurrence in A2-vaccinated (8.3%) and control groups (14.8%) at 26-month median follow-up.

CONCLUSIONS

HLA restriction limits potential use of peptide-based cancer vaccines. This trial demonstrates that HLA-A3 patients respond similarly to E75 vaccination as HLA-A2 patients, suggesting the potential use of the E75 vaccine in up to 76% of the population.

Immunization with truncated sequence of Telomerase Reverse Transcriptase induces a specific antitumor response in vivo

To select the MHC-I-binding epitope-rich sequence of mice telomerase reverse transcriptase (mTERT) and study the antitumor immune response induced by truncated TERT through mRNA-transfected dendritic cells (DCs) immunization in mice. The MHC-I-binding epitopes of TERT were predicted using bioinformatics software. The selected sequence of TERT (Truncated mTERT, TERT(t), mTERT cDNA 1776 bp-2942 bp encoding 584 aa-969 aa) was cloned from B16 mouse melanoma cells and inserted into pBluescriptIIKS(+) plasmid downstream of the T7 promoter. TERT(t) RNA was prepared through in vitro transcription. Bone marrow-derived DCs were electroporated with TERT(t) RNA and used to immunize syngeneic naïve mice. The quantity and cytotoxic activity of TERT-specific cytotoxic T lymphocytes (CTLs) in mice spleen were evaluated using IFN-gamma enzyme-linked immunospot (ELISPOT) and Lactate dehydrogenase release assay. The immunoprophylactic effects against TERT positive tumor induced by TERT(t) RNA transfected DC in vivo were evaluated through an immunized-challenged mouse model. TERT(t) was cloned and in vitro transcribed into TERT(t) mRNA. As shown in FCM analysis, the efficiency of DC electroporation is 35.1% (29.7-41.2%). After electroporation, a subtle increase of costimulator and MHC-II molecules were expressed on the cell surface. Immunization of TERT(t) mRNA transfected DCs induced IFN-gamma-secreting CTLs which manifested specific cytotoxic activity against TERT-positive target cells. In a cancer mouse model, vaccination of TERT(t) mRNA-transfected DCs suppressed the growth of TERT positive tumors (p=0.001) and prolong the survival time of tumor-bearing animals (p=0.029). TERT(t) evokes an antitumor immune response in vivo which is targeted to TERT. TERT(t) can be used as an antigeneic sequence to produce anti-TERT tumor vaccine.

Heterogeneous expression of melanoma antigen (hMAGE) mRNA in mesenchymal neoplasia

Recommendations have been advanced recently for the use of cancer/testis (CT) immunotherapy against sarcomas. CT antigens are encoded by cancer-germline genes (e.g., hMAGE family) that are expressed in tumors and male germline cells but typically not in normal tissues. At present, little information is available regarding CT expression in mesenchymal neoplasms, and it remains uncertain whether CT immunotherapy will serve as a viable alternative or adjunct to current sarcoma therapies involving resection, followed by adjuvant radiotherapy and/or chemotherapy. In this study, hMAGEA2, hMAGEA3, hMAGEA4, and hMAGEC1 mRNA content in 21 benign mesenchymal tumors (representing seven histotypes) and 28 primary sarcomas (10 histotypes) was inventoried using real-time-PCR and then compared against hMAGE mRNA expression in non-sarcomatous malignancies, three cell lines, and muscle. hMAGEA2, hMAGEA3, and hMAGEC1 transcripts were infrequent in mesenchymal tissues in general, whereas hMAGEA4 mRNA was present in 84% of all mesenchymal tumors, 100% of non-sarcomatous tumors, all three cell lines, and in four of five muscle samples. Although hMAGEA4 mRNA was detected in four of five muscle preparations, there was no indication that the mRNA was translated into protein. The presence of hMAGEA4 mRNA in muscle, plus the inconsistent and infrequent occurrence of hMAGEA2, hMAGEA3, and hMAGEC1 mRNA within and among mesenchymal tumor histotypes, makes these four hMAGE antigens unlikely candidates for sarcoma-specific immunotherapy.