A COVID-19 peptide vaccine for the induction of SARS-CoV-2 T cell immunity.

T cell immunity is central for the control of viral infections. CoVac-1 is a peptide-based vaccine candidate, composed of SARS-CoV-2 T cell epitopes derived from various viral proteins1,2, combined with the Toll-like receptor 1/2 agonist XS15 emulsified in Montanide ISA51 VG, aiming to induce profound SARS-CoV-2 T cell immunity to combat COVID-19. Here we conducted a phase I open-label trial, recruiting 36 participants aged 18-80 years, who received a single subcutaneous CoVac-1 vaccination. The primary end point was safety analysed until day 56. Immunogenicity in terms of CoVac-1-induced T cell response was analysed as the main secondary end point until day 28 and in the follow-up until month 3. No serious adverse events and no grade 4 adverse events were observed. Expected local granuloma formation was observed in all study participants, whereas systemic reactogenicity was absent or mild. SARS-CoV-2-specific T cell responses targeting multiple vaccine peptides were induced in all study participants, mediated by multifunctional T helper 1 CD4+ and CD8+ T cells. CoVac-1-induced IFNγ T cell responses persisted in the follow-up analyses and surpassed those detected after SARS-CoV-2 infection as well as after vaccination with approved vaccines. Furthermore, vaccine-induced T cell responses were unaffected by current SARS-CoV-2 variants of concern. Together, CoVac-1 showed a favourable safety profile and induced broad, potent and variant of concern-independent T cell responses, supporting the presently ongoing evaluation in a phase II trial for patients with B cell or antibody deficiency.

naRNA-LL37 composite DAMPs define sterile NETs as self-propagating drivers of inflammation.

Neutrophil extracellular traps (NETs) are a key antimicrobial feature of cellular innate immunity mediated by polymorphonuclear neutrophils (PMNs). NETs counteract microbes but are also linked to inflammation in atherosclerosis, arthritis, or psoriasis by unknown mechanisms. Here, we report that NET-associated RNA (naRNA) stimulates further NET formation in naive PMNs via a unique TLR8-NLRP3 inflammasome-dependent pathway. Keratinocytes respond to naRNA with expression of psoriasis-related genes (e.g., IL17, IL36) via atypical NOD2-RIPK signaling. In vivo, naRNA drives temporary skin inflammation, which is drastically ameliorated by genetic ablation of RNA sensing. Unexpectedly, the naRNA-LL37 'composite damage-associated molecular pattern (DAMP)' is pre-stored in resting neutrophil granules, defining sterile NETs as inflammatory webs that amplify neutrophil activation. However, the activity of the naRNA-LL37 DAMP is transient and hence supposedly self-limiting under physiological conditions. Collectively, upon dysregulated NET release like in psoriasis, naRNA sensing may represent both a potential cause of disease and a new intervention target.

Quantitative Metabolomics and Lipoprotein Analysis of PDAC Patients Suggests Serum Marker Categories for Pancreatic Function, Pancreatectomy, Cancer Metabolism, and Systemic Disturbances.

Pancreatic ductal adenocarcinoma (PDAC) is difficult to diagnose in the early stages and lacks reliable biomarkers. The scope of this project was to establish quantitative nuclear magnetic resonance (NMR) spectroscopy to comprehensively study blood serum alterations in PDAC patients. Serum samples from 34 PDAC patients obtained before and after pancreatectomy as well as 83 age- and sex-matched control samples from healthy donors were analyzed with in vitro diagnostics research (IVDr) proton NMR spectroscopy at 600 MHz. Uni- and multivariate statistics were applied to identify significant biofluid alterations. We identified 29 significantly changed metabolites and 98 lipoproteins when comparing serum from healthy controls with those of PDAC patients. The most prominent features were assigned to (i) markers of pancreatic function (e.g., glucose and blood triglycerides), (ii) markers related to surgery (e.g., ketone bodies and blood cholesterols), (iii) PDAC-associated markers (e.g., amino acids and creatine), and (iv) markers for systemic disturbances in PDAC (e.g., gut metabolites DMG, TMAO, DMSO2, and liver lipoproteins). Quantitative serum NMR spectroscopy is suited as a diagnostic tool to investigate PDAC. Remarkably, 2-hydroxybutyrate (2-HB) as a previously suggested marker for insulin resistance was found in extraordinarily high levels only after pancreatectomy, suggesting this metabolite is the strongest marker for pancreatic loss of function.

A Baseline Cellular Antiviral State Is Maintained by cGAS and Its Most Frequent Naturally Occurring Variant rs610913.

Upon recognition of aberrantly located DNA, the innate immune sensor cyclic GMP-AMP synthase (cGAS) activates stimulator of IFN genes (STING)/IFN regulatory factor (IRF)3-driven antiviral responses. In this study, we characterized the ability of a specific variant of the human cGAS-encoding gene MB21D1, rs610913, to alter cGAS-mediated DNA sensing and viral infection. rs610913 is a frequent G>T polymorphism resulting in a P261H exchange in the cGAS protein. Data from the International Collaboration for the Genomics of HIV suggested that rs610913 nominally associates with HIV-1 acquisition in vivo. Molecular modeling of cGAS(P261H) hinted toward the possibility for an additional binding site for a potential cellular cofactor in cGAS dimers. However, cGAS(wild-type [WT]) or cGAS(P261H)-reconstituted THP-1 cGAS knockout cells shared steady-state expression of IFN-stimulated genes, as opposed to cells expressing the enzymatically inactive cGAS(G212A/S213A). Accordingly, cGAS(WT) and cGAS(P261H) cells were less susceptible to lentiviral transduction and infection with HIV-1, HSV-1, and Chikungunya virus as compared with cGAS knockout or cGAS(G212A/S213A) cells. Upon DNA challenge, innate immune activation appeared to be mildly reduced upon expression of cGAS(P261H) compared with cGAS(WT). Finally, DNA challenge of PBMCs from donors homozygously expressing rs610913 provoked a trend toward a slightly reduced type I IFN response as compared with PBMCs from GG donors. Taken together, the steady-state activity of cGAS maintains a baseline antiviral state rendering cells more refractory to IFN-stimulated gene-sensitive viral infections. rs610913 failed to grossly differ phenotypically from the WT gene, suggesting that cGAS(P261H) and WT cGAS share a similar ability to sense viral infections in vivo.

Integrin activation enables rapid detection of functional Vδ1+ and Vδ2+ γδ T cells.

Conformational change of the ß2 integrin lymphocyte function-associated antigen 1 (LFA-1) is an early marker of T cell activation. A protocol using the mAb clone m24 recognizing the active, extended high-affinity conformation has been previously described for the assessment of functional CD4+ and CD8+ T cells in response to MHC-peptide stimulation. We investigated the applicability of the m24 mAb to detect the activation of γδ T cells in response to different soluble and immobilized stimuli. m24 mAb staining was associated with the expression of cytokines and was detectable as early as 10 min after stimulation, but with different kinetics depending on the nature of the stimulus. Hence, we conclude that this assay is suitable for the detection of functional γδ T cells and allows the assessment of activation more rapidly than alternative methods such as cytokine detection. Intracellular staining, protein trafficking inhibitors, or prior knowledge of the stimulating moiety recognized are no longer required for monitoring γδ T cell activation.

[Impact of the SARS-CoV-2 Pandemic on Liver Surgery and Liver Transplantations in Germany]. / Einfluss der Coronapandemie auf die Leberchirurgie und Lebertransplantationen in Deutschland.

BACKGROUND: The SARS-CoV-2 pandemic has led to restrictions in surgical care worldwide and therefore also posed new challenges to liver surgery. The respective procedures often entail high perioperative risks and resource requirements. However, the indication for liver surgery is frequently without alternatives. To date, there is little knowledge about the impact of the pandemic on liver surgery in Germany. METHODS: A retrospective data analysis of liver surgery procedures in Germany as well as transplantations was conducted. Evaluations were based on procedure codes recorded between 2010 and 2020 according to diagnosis-related groups (DRG) by the Federal Statistical Office of Germany (Destatis) and data from the German Organ Procurement Organization (Deutsche Stiftung Organtransplantation; DSO). RESULTS: According to DRG procedure codes relating to liver surgery recorded between 2010 and 2020 in Germany, the annual fluctuation for the first year of the pandemic 2020 remained comparable to previous years. Furthermore, the development of post-mortem liver transplantations as well as living liver donations remained stable in Germany in 2020 and 2021. CONCLUSIONS: The number of liver surgery procedures in Germany was subject to a dynamic development until 2020, without apparent changes in the first year of the SARS-CoV-2 pandemic. The most frequently performed liver procedures, as well as liver transplantations, remained stable with respect to their annually recorded numbers. Publication of data regarding procedures in liver surgery and transplantation in 2021 need to be awaited and analyzed to evaluate whether the observations presented in this article prove stable any further.

A Prospective, Phase I/II, Open-Label Pilot Trial to Assess the Safety of Hyperthermic Intraperitoneal Chemotherapy After Oncological Resection of Pancreatic Adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a common fatal disease with unfavorable prognosis, even after oncological resection. To improve survival, adding hyperthermic intraperitoneal chemotherapy (HIPEC) has been suggested. Whether HIPEC entails disproportional short-term mortality is unknown and a prospectively determined adverse events profile is lacking. Since both pancreatic resection and HIPEC may relevantly influence morbidity and mortality, this uncontrolled single-arm, open-label, phase I/II pilot trial was designed to assess the 30-day mortality rate, treatment feasibility, and adverse events connected with HIPEC after oncological pancreatic surgery. METHODS: This trial recruited patients scheduled for PDAC resection. A sample size of 16 patients receiving study interventions was estimated to establish a predefined margin of treatment-associated short-term mortality with a power of > 80%. Patients achieving complete macroscopic resection received HIPEC with gemcitabine administered at 1000 mg/m2 body surface area heated to 42 °C for 1 hour. RESULTS: Within 30 days after intervention, no patient died or experienced any adverse events higher than grade 3 that were related to HIPEC. Furthermore, treatment-related adverse events were prospectively documented and categorized as expected or unexpected. This trial supports that the actual mortality rate after PDAC resection and HIPEC is below 10%. HIPEC treatment proved feasible in 89% of patients allocated to intervention. Pancreatic fistulas, as key complications after pancreas surgery, occurred in 3/13 patients under risk. CONCLUSION: Combined pancreas resection and gemcitabine HIPEC proved feasible and safe, with acceptable morbidity and mortality. Based on these results, further clinical evaluation can be justified. REGISTRATION NUMBER: NCT02863471 ( http://www.clinicaltrials.gov ).

[SARS-CoV-2 Infections and Clinical Consequences in a Cohort of Solid Organ Transplant Recipients during the first Wave in Germany - a Single Centre Survey and a Case Report]. / SARS-CoV-2-Infektionen und klinische Konsequenzen bei organtransplantierten Patienten im Rahmen der ersten Ansteckungswelle in Deutschland - eine monozentrische Umfrage und ein Fallbericht.

BACKGROUND: The SARS-CoV-2 pandemic has caused an unprecedented global health crisis, with exceptionally high mortality rates in high-risk groups of affected patients. It is alarming that a steadily increasing number of clinical reports on outcomes of COVID-19 in solid organ transplant (SOT) recipients suggests a detrimental impact linked to high overall mortality. However, systematic data on SARS-CoV-2 infections in SOT recipients in Germany are still scarce. MATERIAL AND METHODS: We conducted a survey on SARS-CoV-2 infection status among 387 SOT recipients treated at our centre during the past 5 years - located in a severely affected region in Germany. The survey was sent out two months after the first SARS CoV-2 outbreak in our region had resulted in government-imposed lockdown measures. RESULTS: An incidence rate of 0.4% SARS-CoV-2-positive SOT recipients was determined in our cohort, in line with reported local infection rates in the general population at this time. However, the only SARS CoV-2 infection known to us within this group of patients led to severe morbidity - resulting in prolonged mechanical ventilation, hospitalisation > 60 days and finally in irreversible loss of graft function. CONCLUSION: Our data demonstrate that SOT recipients are at equal risk for SARS-CoV-2 infections when compared to the general population, while SARS-CoV-2 infections in SOT recipients seem to be associated with deleterious clinical consequences.

The immunopeptidomic landscape of ovarian carcinomas.

Immunotherapies, particularly checkpoint inhibitors, have set off a revolution in cancer therapy by releasing the power of the immune system. However, only little is known about the antigens that are essentially presented on cancer cells, capable of exposing them to immune cells. Large-scale HLA ligandome analysis has enabled us to exhaustively characterize the immunopeptidomic landscape of epithelial ovarian cancers (EOCs). Additional comparative profiling with the immunopeptidome of a variety of benign sources has unveiled a multitude of ovarian cancer antigens (MUC16, MSLN, LGALS1, IDO1, KLK10) to be presented by HLA class I and class II molecules exclusively on ovarian cancer cells. Most strikingly, ligands derived from mucin 16 and mesothelin, a molecular axis of prognostic importance in EOC, are prominent in a majority of patients. Differential gene-expression analysis has allowed us to confirm the relevance of these targets for EOC and further provided important insights into the relationship between gene transcript levels and HLA ligand presentation.

[Individualized immunotherapy for malignant tumors using peptide vaccines-maybe it does work after all?] / Individualisierte Immuntherapie von Tumorerkrankungen mittels Peptidimpfstoffen ­ Funktioniert das vielleicht doch?

The physician and scientist Paul Ehrlich put forward the thesis that the immune system not only fights infections but can also fight cancer. The possible positive effects of a simultaneous infection on the course of cancer were reported in ancient Egypt around 2600 BC. However, it was not until the 1960s that it became apparent that the immune system could specifically fight cancer cells, and it was not until the 1990s that researchers slowly clarified how this happens.Against this background, the efforts over the last 30 years to develop therapeutic vaccines against cancers are briefly summarized, and their lack of success to date is highlighted. In addition, potentially promising future developments in this context are discussed. The available scientific literature as well as our own results are taken into account.Central questions arise, such as the following: How do cancer cells differ from normal cells? How can the immune system recognize these differences? What are tumor-specific antigens? Why do they need to be selected and applied in an individualized fashion? How can an efficient immune response be induced? Which pharmaceutical formulations, adjuvants, and vaccination routes are effective?Finally, we explain why it may still be worth pursuing peptide vaccination, which has so far been completely unsuccessful (when measured in terms of already approved therapeutics).

A comprehensive quality control workflow for paired tumor-normal NGS experiments.

SUMMARY: Quality control (QC) is an important part of all NGS data analysis stages. Many available tools calculate QC metrics from different analysis steps of single sample experiments (raw reads, mapped reads and variant lists). Multi-sample experiments, as sequencing of tumor-normal pairs, require additional QC metrics to ensure validity of results. These multi-sample QC metrics still lack standardization. We therefore suggest a new workflow for QC of DNA sequencing of tumor-normal pairs. With this workflow well-known single-sample QC metrics and additional metrics specific for tumor-normal pairs can be calculated. The segmentation into different tools offers a high flexibility and allows reuse for other purposes. All tools produce qcML, a generic XML format for QC of -omics experiments. qcML uses quality metrics defined in an ontology, which was adapted for NGS. AVAILABILITY AND IMPLEMENTATION: All QC tools are implemented in C ++ and run both under Linux and Windows. Plotting requires python 2.7 and matplotlib. The software is available under the 'GNU General Public License version 2' as part of the ngs-bits project: https://github.com/imgag/ngs-bits. CONTACT: christopher.schroeder@med.uni-tuebingen.de. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

First case report of malignant peritoneal mesothelioma and oral verrucous carcinoma in a patient with a germline PTEN mutation: a combination of extremely rare diseases with probable further implications.

BACKGROUND: The PTEN-hamartoma-tumor-syndrome (PHTS) is caused by germline mutations in Phosphatase and Tensin homolog (PTEN) and predisposes to the development of several typical malignancies. Whereas PTEN mutations have been implicated in the occurrence of malignant mesotheliomas, the genetic landscape of verrucous carcinomas (VC) is largely uncharted. Both VC and malignant peritoneal mesotheliomas (MPM) are exceedingly rare and a potential link between these malignancies and PHTS has never been reported. CASE PRESENTATION: We here describe the clinical course of a PHTS patient who, in addition to a typical thyroid carcinoma at the age of 36 years, developed a highly-differentiated oral VC and an epithelioid MPM six years later. The patient with a history of occupational asbestos exposure underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for MPM. The clinical diagnosis of PHTS was consequently corroborated by a germline PTEN deletion. Sequencing of tumor tissue revealed a second hit in PTEN in the thyroid carcinoma and VC, confirmed by a PTEN loss and activation of the PI3K/AKT pathway in immunohistochemistry. Furthermore, additional somatic mutations in the thyroid carcinoma as well as in the VC were detected, whereas the genetics of MPM remained unrevealing. DISCUSSION AND CONCLUSIONS: We here report the very unusual clinical course of a patient with rare tumors that have a germline mutation first hit in PTEN in common. Since this patient was exposed to asbestos and current evidence suggests molecular mechanisms that might render PHTS patients particularly susceptible to mesothelioma, we strongly recommend PHTS patients to avoid even minimal exposure.

Pharmacodynamics of Oxaliplatin-Derived Platinum Compounds During Hyperthermic Intraperitoneal Chemotherapy (HIPEC): An Emerging Aspect Supporting the Rational Design of Treatment Protocols.

BACKGROUND: Hyperthermic intraperitoneal chemotherapy (HIPEC) is used to treat peritoneal surface malignancies with application of cytostatic drugs such as oxaliplatin (OX) after cytoreductive surgery. Despite its increased use, evidence for optimal drug dosage, and notably duration of HIPEC, is scarce. METHODS: In this study, OX distribution was comprehensively assessed in nine patients during HIPEC (300 mg OX/m2 body surface area in Physioneal solution for 30 min). Oxaliplatin and its derivatives were measured in peritoneal perfusates over time by liquid chromatography coupled with mass spectrometry (LC-MS), and the resulting total platinum concentration in tissue was analyzed by atomic absorption spectrometry. Additionally, a novel impedance-based real-time cytotoxicity assay was used to evaluate the bioactivity of perfusates ex vivo. RESULTS: Compared with amounts of OX expected in peritoneal perfusates by calculation, only 10-15% of the parent drug could be detected by LC-MS during HIPEC. Notably, the study additionally detected platinum compounds consistent with OX transformation, accounting for a further fraction of the applied drug. The cytotoxic properties of perfusates remained unchanged during HIPEC, with only a slight but significant attenuation evidenced after 30 min. CONCLUSIONS: The bioactivity of peritoneal perfusates ex vivo is a useful parameter for evaluating the actual cytotoxic potential of OX and its derivatives used in HIPEC over time, overcoming important limitations and disadvantages associated with respective drug monitoring only. Ex vivo cytotoxicity assays may be a promising tool to aid guiding future standardization and harmonization of HIPEC protocols based on drug-mediated effects.

Haploidentical hematopoietic cell transplantation using in vitro T cell depleted grafts as salvage therapy in patients with disease relapse after prior allogeneic transplantation.

Disease relapse after one or more allogeneic hematopoietic cell transplantations (HCT) represents a therapeutic challenge with all options bearing a significant morbidity and mortality. Haploidentical HCT may induce more pronounced anti-leukemic effects and was evaluated at our center in 25 consecutive patients with disease relapse after preceding HCT receiving haploidentical grafts after in vitro T cell depletion. Overall survival at 1 and 2 years was 32 and 14%, respectively. Of note, patients with complete remission (CR) before haploidentical HCT had a very favorable overall survival of 41.7% at 2 years. Cumulative incidence of non-relapse mortality was 36 and 40% at 1 and 2 years, respectively. With a cumulative incidence for relapse of 36 and 45.6% at 1 and 2 years, disease-free survival (DFS) was 28 and 14.4%, respectively. Here also, patients with CR before haploidentical HCT had a favorable DFS of 42% at 2 years. Only very limited acute (11 patients (44%) with a median grade 1) and chronic graft versus host disease (GvHD) (5 patients (11%), limited grade only) was observed. The main complications and causes of death comprised-besides relapse-infections and bleeding complications. Hence, haploidentical HCT can achieve long-term survival comparable to second transplantation with matched or mismatched donors for patients with otherwise deleterious prognosis and should be considered as a treatment option for patients experiencing disease relapse after previous allogeneic HCT.

Personalized peptide vaccine-induced immune response associated with long-term survival of a metastatic cholangiocarcinoma patient.

BACKGROUND & AIMS: We report a novel experimental immunotherapeutic approach in a patient with metastatic intrahepatic cholangiocarcinoma. In the 5year course of the disease, the initial tumor mass, two local recurrences and a lung metastasis were surgically removed. Lacking alternative treatment options, aiming at the induction of anti-tumor T cells responses, we initiated a personalized multi-peptide vaccination, based on in-depth analysis of tumor antigens (immunopeptidome) and sequencing. METHODS: Tumors were characterized by immunohistochemistry, next-generation sequencing and mass spectrometry of HLA ligands. RESULTS: Although several tumor-specific neo-epitopes were predicted in silico, none could be validated by mass spectrometry. Instead, a personalized multi-peptide vaccine containing non-mutated tumor-associated epitopes was designed and applied. Immunomonitoring showed vaccine-induced T cell responses to three out of seven peptides administered. The pulmonary metastasis resected after start of vaccination showed strong immune cell infiltration and perforin positivity, in contrast to the previous lesions. The patient remains clinically healthy, without any radiologically detectable tumors since March 2013 and the vaccination is continued. CONCLUSIONS: This remarkable clinical course encourages formal clinical studies on adjuvant personalized peptide vaccination in cholangiocarcinoma. LAY SUMMARY: Metastatic cholangiocarcinomas, cancers that originate from the liver bile ducts, have very limited treatment options and a fatal prognosis. We describe a novel therapeutic approach in such a patient using a personalized multi-peptide vaccine. This vaccine, developed based on the characterization of the patient's tumor, evoked detectable anti-tumor immune responses, associating with long-term tumor-free survival.

A frequent hypofunctional IRAK2 variant is associated with reduced spontaneous hepatitis C virus clearance.

UNLABELLED: Patients carrying very rare loss-of-function mutations in interleukin-1 receptor-associated kinase 4 (IRAK4), a critical signaling mediator in Toll-like receptor signaling, are severely immunodeficient, highlighting the paramount role of IRAK kinases in innate immunity. We discovered a comparatively frequent coding variant of the enigmatic human IRAK2, L392V (rs3844283), which is found homozygously in ∼15% of Caucasians, to be associated with a reduced ability to induce interferon-alpha in primary human plasmacytoid dendritic cells in response to hepatitis C virus (HCV). Cytokine production in response to purified Toll-like receptor agonists was also impaired. Additionally, rs3844283 was epidemiologically associated with a chronic course of HCV infection in two independent HCV cohorts and emerged as an independent predictor of chronic HCV disease. Mechanistically, IRAK2 L392V showed intact binding to, but impaired ubiquitination of, tumor necrosis factor receptor-associated factor 6, a vital step in signal transduction. CONCLUSION: Our study highlights IRAK2 and its genetic variants as critical factors and potentially novel biomarkers for human antiviral innate immunity.

Long-term recurrence-free survival following pancreatic surgery with HIPEC treatment for locally advanced pancreatic adenocarcinoma.

More than 5 years previous to this report, a female patient in her 60s underwent oncological left-sided pancreatic resection and adrenalectomy including splenectomy for locally advanced pancreatic adenocarcinoma (PDAC), recommended by a multidisciplinary tumour board (MDT). Additionally, she was treated with gemcitabine-containing hyperthermic intraperitoneal chemotherapy (HIPEC) for 60 minutes in the framework of a clinical trial (PanHIPEC), aiming to determine the safety and feasibility (not efficacy) of this approach. Following the postoperative MDT recommendation, she subsequently received adjuvant chemotherapy consisting of six cycles of gemcitabine and cisplatin for a histopathologically confirmed PDAC of the pancreatic tail with infiltration of the left-sided adrenal gland (pT3, pN1 (3/16), cM0, L0, V0, Pn1, R0, G2). Five years and five months after pancreatic surgery and HIPEC, the patient has no signs of tumour recurrence as determined by follow-up examination including CT scan and CA19-9 tumour marker serology.

Identification and relative abundance of naturally presented and cross-reactive influenza A virus MHC class I-restricted T cell epitopes.

Cytotoxic T lymphocytes are key for controlling viral infection. Unravelling CD8+ T cell-mediated immunity to distinct influenza virus strains and subtypes across prominent HLA types is relevant for combating seasonal infections and emerging new variants. Using an immunopeptidomics approach, naturally presented influenza A virus-derived ligands restricted to HLA-A*24:02, HLA-A*68:01, HLA-B*07:02, and HLA-B*51:01 molecules were identified. Functional characterization revealed multifunctional memory CD8+ T cell responses for nine out of sixteen peptides. Peptide presentation kinetics was optimal around 12 h post infection and presentation of immunodominant epitopes shortly after infection was not always persistent. Assessment of immunogenic epitopes revealed that they are highly conserved across the major zoonotic reservoirs and may contain a single substitution in the vicinity of the anchor residues. These findings demonstrate how the identified epitopes promote T cell pools, possibly cross-protective in individuals and can be potential targets for vaccination.

Peptide-stimulated T cells bypass immune checkpoint inhibitor resistance and eliminate autologous microsatellite instable colorectal cancer cells.

Two hypermutated colon cancer cases with patient-derived cell lines, peripheral and tumor-infiltrating T cells available were selected for detailed investigation of immunological response.T cells co-cultured with autologous tumor cells showed only low levels of pro-inflammatory cytokines and failed at tumor recognition. Similarly, treatment of co-cultures with immune checkpoint inhibitors (ICI) did not boost antitumor immune responses. Since proteinase inhibitor 9 (PI-9) was detected in tumor cells, a specific inhibitor (PI-9i) was used in addition to ICI in T cell cytotoxicity testing. However, only pre-stimulation with tumor-specific peptides (cryptic and neoantigenic) significantly increased recognition and elimination of tumor cells by T cells independently of ICI or PI-9i.We showed, that ICI resistant tumor cells can be targeted by tumor-primed T cells and also demonstrated the superiority of tumor-naïve peripheral blood T cells compared to highly exhausted tumor-infiltrating T cells. Future precision immunotherapeutic approaches should include multimodal strategies to successfully induce durable anti-tumor immune responses.