Contrasting frequencies of antitumor and anti-vaccine T cells in metastases of a melanoma patient vaccinated with a MAGE tumor antigen

Melanoma patients have high frequencies of T cells directed against antigens of their tumor. The frequency of these antitumor T cells in the blood is usually well above that of the anti-vaccine T cells observed after vaccination with tumor antigens. In a patient vaccinated with a MAGE-3 antigen presented by HLA-A1, we measured the frequencies of anti-vaccine and antitumor T cells in several metastases to evaluate their respective potential contribution to tumor rejection. The frequency of anti–MAGE-3.A1 T cells was 1.5 × 10−5 of CD8 T cells in an invaded lymph node, sixfold higher than in the blood. An antitumor cytotoxic T lymphocyte (CTL) recognizing a MAGE-C2 antigen showed a much higher enrichment with a frequency of ∼10%, 1,000 times higher than its blood frequency. Several other antitumor T clonotypes had frequencies >1%. Similar findings were made on a regressing cutaneous metastasis. Thus, antitumor T cells were ∼10,000 times more frequent than anti-vaccine T cells inside metastases, representing the majority of T cells present there. This suggests that the anti-vaccine CTLs are not the effectors that kill the bulk of the tumor cells, but that their interaction with the tumor generates conditions enabling the stimulation of large numbers of antitumor CTLs that proceed to destroy the tumor cells. Naive T cells appear to be stimulated in the course of this process as new antitumor clonotypes arise after vaccination

Review of the 25th annual scientific meeting of the International Society for Biological Therapy of Cancer

Led by key opinion leaders in the field, the 25th Annual Meeting of the International Society for Biological Therapy of Cancer (iSBTc, recently renamed the Society for Immunotherapy of Cancer, SITC) provided a scientific platform for ~500 attendees to exchange cutting-edge information on basic, clinical, and translational research in cancer immunology and immunotherapy. The meeting included keynote addresses on checkpoint blockade in cancer therapy and recent advances in therapeutic vaccination against cancer induced by Human Papilloma Virus 16. Participants from 29 countries interacted through oral presentations, panel discussions, and posters on topics that included dendritic cells and cancer, targeted therapeutics and immunotherapy, innate/adaptive immune interplay in cancer, clinical trial endpoints, vaccine combinations, countering negative regulation, immune cell trafficking to tumor microenvironment, and adoptive T cell transfer. In addition to the 50 oral presentations and >180 posters on these topics, a new SITC/iSBTc initiative to create evidence-based Cancer Immunotherapy Guidelines was announced. The SITC/iSBTc Biomarkers Taskforce announced the release of recommendations on immunotherapy biomarkers and a highly successful symposium on Immuno-Oncology Biomarkers that took place on the campus of the National Institutes of Health (NIH) immediately prior to the Annual Meeting. At the Annual Meeting, the NIH took the opportunity to publicly announce the award of the U01 grant that will fund the Cancer Immunotherapy Trials Network (CITN). In summary, the Annual Meeting gathered clinicians and scientists from academia, industry, and regulatory agencies from around the globe to interact and exchange important scientific advances related to tumor immunobiology and cancer immunotherapy

TCR Gene Transfer: MAGE-C2/HLA-A2 and MAGE-A3/HLA-DP4 Epitopes as Melanoma-Specific Immune Targets

Adoptive therapy with TCR gene-engineered T cells provides an attractive and feasible treatment option for cancer patients. Further development of TCR gene therapy requires the implementation of T-cell target epitopes that prevent “on-target” reactivity towards healthy tissues and at the same time direct a clinically effective response towards tumor tissues. Candidate epitopes that meet these criteria are MAGE-C2336-344/HLA-A2 (MC2/A2) and MAGE-A3243-258/HLA-DP4 (MA3/DP4). We molecularly characterized TCRαβ genes of an MC2/A2-specific CD8 and MA3/DP4-specific CD4 T-cell clone derived from melanoma patients who responded clinically to MAGE vaccination. We identified MC2/A2 and MA3/DP4-specific TCR-Vα3/Vβ28 and TCR-Vα38/Vβ2 chains and validated these TCRs in vitro upon gene transfer into primary human T cells. The MC2 and MA3 TCR were surface-expressed and mediated CD8 T-cell functions towards melanoma cell lines and CD4 T-cell functions towards dendritic cells, respectively. We intend to start testing these MAGE-specific TCRs in phase I clinical trial

High frequency of antitumor T cells in the blood of melanoma patients before and after vaccination with tumor antigens

After vaccination of melanoma patients with MAGE antigens, we observed that even in the few patients showing tumor regression, the frequency of anti-vaccine T cells in the blood was often either undetectable or <10−5 of CD8 T cells. This frequency being arguably too low for these cells to be sole effectors of rejection, we reexamined the contribution of T cells recognizing other tumor antigens. The presence of such antitumor T cells in melanoma patients has been widely reported. To begin assessing their contribution to vaccine-induced rejection, we evaluated their blood frequency in five vaccinated patients. The antitumor cytotoxic T lymphocyte (CTL) precursors ranged from 10−4 to 3 × 10−3, which is 10–10,000 times higher than the anti-vaccine CTL in the same patient. High frequencies were also observed before vaccination. In a patient showing nearly complete regression after vaccination with a MAGE-3 antigen, we observed a remarkably focused antitumoral response. A majority of CTL precursors (CTLp's) recognized antigens encoded by MAGE-C2, another cancer-germline gene. Others recognized gp100 antigens. CTLp's recognizing MAGE-C2 and gp100 antigens were already present before vaccination, but new clonotypes appeared afterwards. These results suggest that a spontaneous antitumor T cell response, which has become ineffective, can be reawakened by vaccination and contribute to tumor rejection. This notion is reinforced by the frequencies of anti-vaccine and antitumor CTLs observed inside metastases, as presented by Lurquin et al. (Lurquin, C., B. Lethé, V. Corbière, I. Théate, N. van Baren, P.G. Coulie, and T. Boon. 2004. J. Exp. Med. 201:249–257)

Long Overall Survival After Dendritic Cell Vaccination in Metastatic Uveal Melanoma Patients

Purpose: To assess the safety and efficacy of dendritic cell vaccination in metastatic uveal melanoma. Design: Interventional case series. Methods: We analyzed 14 patients with metastatic uveal melanoma treated with dendritic cell vaccination. Patients with metastatic uveal melanoma received at least 3 vaccinations with autologous dendritic cells, professional antigen-presenting cells loaded with melanoma antigens gp100 and tyrosinase. The main outcome measures were safety, immunologic response, and overall survival. Results: Tumor-specific immune responses were induced with dendritic cell vaccination in 4 (29%) of14 patients. Dendritic cell-vaccinated patients showed a median overall survival with metastatic disease of 19.2months, relatively long compared with that reported in the literature. No severe treatment-related toxicities (common toxicity criteria grade 3 or 4) were observed. Conclusions: Dendritic cell vaccination is feasible and safe in metastatic uveal melanoma. Dendritic cell-based immunotherapy is potent to enhance the host's antitumor immunity against uveal melanoma in approximately one third of patients. Compared with other prospective studies with similar inclusion criteria, dendritic cell vaccination may be associated with longer than average overall survival in patients with metastatic uveal melanoma

Intraoperative ketorolac in high-risk breast cancer patients : A prospective, randomized, placebo-controlled clinical trial

Funding: This work is financed by grants received by PF, in the name of his institution: the Anticancer Fund (no grant number) (www.anticancerfund.org); the Belgian Society of Anaesthesia and Resuscitation (no grant number) (www.sarb.be); the Fondation Saint-Luc (no grant number) (www.uclouvain.be); the Commission du Patrimoine of the Université catholique de Louvain, St-Luc Hospital (exceptional grant, no number) (www.uclouvain.be). None of the funders had any role in the study design, data collection and analysis, decision to publish or preparation of the manuscript except the scientific advise of GB, scientific director of the Anticancer Fund.Peer reviewedPublisher PD

A Human Minor Histocompatibility Antigen Specific for B Cell Acute Lymphoblastic Leukemia

Human minor histocompatibility antigens (mHags) play an important role in the induction of cytotoxic T lymphocyte (CTL) reactivity against leukemia after human histocompatibility leukocyte antigen (HLA)-identical allogeneic bone marrow transplantation (BMT). As most mHags are not leukemia specific but are also expressed by normal tissues, antileukemia reactivity is often associated with life-threatening graft-versus-host disease (GVHD). Here, we describe a novel mHag, HB-1, that elicits donor-derived CTL reactivity in a B cell acute lymphoblastic leukemia (B-ALL) patient treated by HLA-matched BMT. We identified the gene encoding the antigenic peptide recognized by HB-1–specific CTLs. Interestingly, expression of the HB-1 gene was only observed in B-ALL cells and Epstein-Barr virus–transformed B cells. The HB-1 gene–encoded peptide EEKRGSLHVW is recognized by the CTL in association with HLA-B44. Further analysis reveals that a polymorphism in the HB-1 gene generates a single amino acid exchange from His to Tyr at position 8 within this peptide. This amino acid substitution is critical for recognition by HB-1–specific CTLs. The restricted expression of the polymorphic HB-1 Ag by B-ALL cells and the ability to generate HB-1–specific CTLs in vitro using peptide-loaded dendritic cells offer novel opportunities to specifically target the immune system against B-ALL without the risk of evoking GVHD

Selective cancer-germline gene expression in pediatric brain tumors

Cancer-germline genes (CGGs) code for immunogenic antigens that are present in various human tumors and can be targeted by immunotherapy. Their expression has been studied in a wide range of human tumors in adults. We measured the expression of 12 CGGs in pediatric brain tumors, to identify targets for therapeutic cancer vaccines. Real Time PCR was used to quantify the expression of genes MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A4, MAGE-A6, MAGE-A10, MAGE-A12, MAGE-C2, NY-ESO-1 and GAGE-1,2,8 in 50 pediatric brain tumors of different histological subtypes. Protein expression was examined with immunohistochemistry. Fifty-five percent of the medulloblastomas (n = 11), 86% of the ependymomas (n = 7), 40% of the choroid plexus tumors (n = 5) and 67% of astrocytic tumors (n = 27) expressed one or more CGGs. Immunohistochemical analysis confirmed qPCR results. With exception of a minority of tumors, the overall level of CGG expression in pediatric brain tumors was low. We observed a high expression of at least one CGG in 32% of the samples. CGG-encoded antigens are therefore suitable targets in a very selected group of pediatric patients with a brain tumor. Interestingly, glioblastomas from adult patients expressed CGGs more often and at significantly higher levels compared to pediatric glioblastomas. This observation is in line with the notion that pediatric and adult glioblastomas develop along different genetic pathways

Folding of Matrix Metalloproteinase-2 Prevents Endogenous Generation of MHC Class-I Restricted Epitope

BACKGROUND: We previously demonstrated that the matrix metalloproteinase-2 (MMP-2) contained an antigenic peptide recognized by a CD8 T cell clone in the HLA-A*0201 context. The presentation of this peptide on class I molecules by human melanoma cells required a cross-presentation mechanism. Surprisingly, the classical endogenous processing pathway did not process this MMP-2 epitope. METHODOLOGY/PRINCIPAL FINDINGS: By PCR directed mutagenesis we showed that disruption of a single disulfide bond induced MMP-2 epitope presentation. By Pulse-Chase experiment, we demonstrated that disulfide bonds stabilized MMP-2 and impeded its degradation. Finally, using drugs, we documented that mutated MMP-2 epitope presentation used the proteasome and retrotranslocation complex. CONCLUSIONS/SIGNIFICANCE: These data appear crucial to us since they established the existence of a new inhibitory mechanism for the generation of a T cell epitope. In spite of MMP-2 classified as a self-antigen, the fact that cross-presentation is the only way to present this MMP-2 epitope underlines the importance to target this type of antigen in immunotherapy protocols