Peptide Vaccine Research Articles

Evaluation of a Novel Multi-Epitope Peptide Vaccine Candidate from LACK, LeIF, GP63, SMT Antigens of Leishmania major in BALB/c Mice.

Leishmaniasis is one of the major health problems in most countries of the world. Millions of people around the world are at risk for the disease. Given the prevalence of this parasite in Iran and developing countries and the emergence of resistance in some cases to existing drugs, developing an effective vaccine against leishmaniasis is necessary. This research aims to design a multi-epitope vaccine derived from LACK, LeIF, GP63, and SMT antigens of Leishmania major based on the combination of bioinformatics methods. The synthesized construct with 16.86 KDa was cloned and sub-cloned in pEGFP- N1 and pLEXSY-neo2, respectively. They were then transfected in promastigotes of L. tarentolae. After confirmation of expression, immunization was carried out in 8 groups of BALB/c mice (9 mice per group) three times at two-week intervals. Cellular immune responses were assessed before and after the challenge by L. major. Furthermore, at 3rd week post-infection, the survival rate, mean lesion size, and parasite burden were assessed. All vaccinated mice demonstrated partial immunity to higher IFN-γ levels than the control groups (P<0.05). Immunized mice with cytosolic complex (G1) indicated the highest levels of IFN-ɤ and ratio of IFN ɤ/ IL-4, the lowest levels of IL-4 and IL-10 compared to control and the other groups (P≤0.05), and produced a partial Th1 immune response. Mean lesion size and parasite burden of G1 and G5 reduced significantly compared to the other and control groups post-challenge (P<0.05). The outputs of our result could be a hopeful sign in the achievement of practical approaches as multi-epitope vaccines against Leishmania major.

180P Recalling pre-existing microbiota-specific T cells to target tumors

The gut microbiome has the singular property of shaping the immune system through a multitude of antigens that educate the T cell repertoire. Since microbial peptides can share similarities with tumor antigens, cross-reactive memory T cells that recognize both bacterial and tumor-derived peptides can thus emerge from the imprinting of the T cell repertoire by gut commensals. Harnessing the full potential of cross-reactive CD8+ T cells against tumor cells could therefore be achieved through the rational design of a microbiota-derived peptide vaccine.

TGFβ-derived immune modulatory vaccine: targeting the immunosuppressive and fibrotic tumor microenvironment in a murine model of pancreatic cancer

BackgroundPancreatic ductal adenocarcinoma (PDAC) is associated with very poor survival, making it the third and fourth leading cause of all cancer-related deaths in the USA and European Union, respectively. The...

Abstract IA016: Lessons learned from clinical trials of MUC1 peptide vaccines for cancer prevention

Abstract We report on three trials of a MUC1 peptide vaccine for cancer prevention. Two trials were pilot studies evaluating vaccine immunogenicity and safety. One was in subjects with advanced colon adenomas, and the other in smokers at risk for lung cancer. The third trial was a multi-center, randomized placebo-controlled trial in subjects with advanced adenoma that included an assessment of the clinical efficacy of the vaccine to prevent recurrent adenoma. All trials successfully recruited their full complement of participants and the vaccine was well tolerated with no safety concerns. The response rate in the colon adenoma trials was 43% in the pilot study and 25% in the placebo- controlled multicenter trial. Only 10% of smokers responded to the vaccine. Higher levels of circulating myeloid derived suppressor cells (MDSC) were consistently associated with the lack of an immune response. This suggests that even in pre-malignancy immunosuppressive tendencies can impair vaccine immunogenicity. Responders to the vaccine demonstrated immune memory at one year. In the multicenter adenoma trial that evaluated the efficacy of the vaccine on adenoma recurrence, immune responders demonstrated an association with a reduced rate of adenoma recurrence. In future studies, patient selection based on circulating MDSC levels, or concomitant use of agents to counter MDSC immunosuppressive function or otherwise improve T cell function, should be considered. Citation Format: Robert E. Schoen. Lessons learned from clinical trials of MUC1 peptide vaccines for cancer prevention [abstract]. In: Proceedings of the Second Biennial NCI Meeting: Translational Advances in Cancer Prevention Agent Development (TACPAD); 2022 Sep 7-9. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_2): Abstract nr IA016.

LBA6 UCPVax therapeutic vaccination promotes cytotoxic and Th1 polarized antitumor CD4 T cells and epitope spreading in patients with advanced non-small cell lung cancer

The stimulation of antitumor CD4 T helper response represents a critical requirement for therapeutic cancer vaccine effectiveness. In this context, we developed a Th1-inducer anticancer peptide vaccine derived from telomerase called UCPVax (Dosset et al. Clin Can Res 2012). The safety and efficacy of UCPVax therapeutic vaccination were recently reported in metastatic non-small cell lung cancer (NSCLC) phase I/II trial (Adotévi et al., J Clin Oncol 2022, NCT02818426). Here, we described the immunological responses promoted by UCPVax.

In Silico Screening of Prospective MHC Class I and II Restricted T-Cell Based Epitopes of the Spike Protein of SARS-CoV-2 for Designing of a Peptide Vaccine for COVID-19

Multiple vaccines were developed and administered to immunize people worldwide against SARS-CoV-2 infection. However, changes in platelet count following the course of vaccination have been reported by many studies, suggesting vaccine-induced thrombocytopenia. In this context, designing an effective targeted subunit vaccine with high specificity and efficiency for people with low platelet counts has become a challenge for researchers. Using the in silico-based approaches and methods, the present study explored the antigenic epitopes of the spike protein of SARS-CoV-2 involved in initial binding of the virus with the angiotensin converting enzyme-2 receptor (ACE-2) on the respiratory epithelial cells. The top ten major histocompatibility complex-I (MHC-I) and MHC-II restricted epitopes were found to have 95.26% and 99.99% HLA-class-I population coverage, respectively. Among the top ten promiscuous MHC-I restricted epitopes, ’FTISVTTEI’ had the highest global HLA population coverage of 53.24%, with an antigenic score of 0.85 and a docking score of −162.4 Kcal/mol. The epitope ‘KLNDLCFTNV’ had the best antigenic score of 2.69 and an HLA population coverage of 43.4% globally. The study predicted and documented the most suitable epitopes with the widest global HLA coverage for synthesis of an efficient peptide-based vaccine against the deadly COVID-19.

Synthetic Melanin Acts as Efficient Peptide Carrier in Cancer Vaccine Strategy

We previously reported that a novel peptide vaccine platform, based on synthetic melanin nanoaggregates, triggers strong cytotoxic immune responses and significantly suppresses tumor growth in mice. However, the mechanisms underlying such an efficacy remained poorly described. Herein, we investigated the role of dendritic cells (DCs) in presenting the antigen embedded in the vaccine formulation, as well as the potential stimulatory effect of melanin upon these cells, in vitro by coculture experiments and ELISA/flow cytometry analysis. The vaccine efficiency was evaluated in FLT3-L-/- mice constitutively deficient in DC1, DC2, and pDCs, in Zbtb46DTR chimera mice deficient in DC1 and DC2, and in LangerinDTR mice deficient in dermal DC1 and Langerhans cells. We concluded that DCs, and especially migratory conventional type 1 dendritic cells, seem crucial for mounting the immune response after melanin-based vaccination. We also assessed the protective effect of L-DOPA melanin on peptides from enzymatic digestion, as well as the biodistribution of melanin-peptide nanoaggregates, after subcutaneous injection using [18F]MEL050 PET imaging in mice. L-DOPA melanin proved to act as an efficient carrier for peptides by fully protecting them from enzymatic degradation. L-DOPA melanin did not display any direct stimulatory effects on dendritic cells in vitro. Using PET imaging, we detected melanin-peptide nanoaggregates up to three weeks after subcutaneous injections within the secondary lymphoid tissues, which could explain the sustained immune response observed (up to 4 months) with this vaccine technology.

Immunoinformatics Approach for Epitope-Based Vaccine Design: Key Steps for Breast Cancer Vaccine.

Vaccines are an upcoming medical intervention for breast cancer. By targeting the tumor antigen, cancer vaccines can be designed to train the immune system to recognize tumor cells. Therefore, along with technological advances, the vaccine design process is now starting to be carried out with more rational methods such as designing epitope-based peptide vaccines using immunoinformatics methods. Immunoinformatics methods can assist vaccine design in terms of antigenicity and safety. Common protocols used to design epitope-based peptide vaccines include tumor antigen identification, protein structure analysis, T cell epitope prediction, epitope characterization, and evaluation of protein-epitope interactions. Tumor antigen can be divided into two types: tumor associated antigen and tumor specific antigen. We will discuss the identification of tumor antigens using high-throughput technologies. Protein structure analysis comprises the physiochemical, hydrochemical, and antigenicity of the protein. T cell epitope prediction models are widely available with various prediction parameters as well as filtering tools for the prediction results. Epitope characterization such as allergenicity and toxicity can be done in silico as well using allergenicity and toxicity predictors. Evaluation of protein-epitope interactions can also be carried out in silico with molecular simulation. We will also discuss current and future developments of breast cancer vaccines using an immunoinformatics approach. Finally, although prediction models have high accuracy, the opposite can happen after being tested in vitro and in vivo. Therefore, further studies are needed to ensure the effectiveness of the vaccine to be developed. Although epitope-based peptide vaccines have the disadvantage of low immunogenicity, the addition of adjuvants can be a solution.

Evaluation of Immunogenicity and Clinical Protection of SARS-CoV-2 S1 and N Antigens in Syrian Golden Hamster.

The novel coronavirus (SARS-CoV-2) epidemic continues to be a global public crisis affecting human health. Many research groups are developing different types of vaccines to suppress the spread of SARS-CoV-2, and some vaccines have entered phase III clinical trials and have been rapidly implemented. Whether multiple antigen matches are necessary to induce a better immune response remains unclear. To address this question, this study tested the immunogenicity and protective effects of a SARS-CoV-2 recombinant S and N peptide vaccine in the Syrian golden hamster model. This experiment was based on two immunization methods: intradermal and intramuscular administration. Immunized hamsters were challenged with live SARS-CoV-2 14 days after booster immunization. Clinical symptoms were observed daily, and the antibody titer and viral load in each tissue were detected. The results showed that immunization of golden hamsters with the SARS-CoV-2 structural protein S alone or in combination with the N protein through different routes induced antibody responses, whereas immunization with the N protein alone did not. However, although the immunized hamsters exhibited partial alleviation of clinical symptoms when challenged with the virus, neither vaccine effectively inhibited the proliferation and replication of the challenging virus. In addition, the pathological damage in the immunized hamsters was similar to that in the control hamsters. Interestingly, the neutralizing antibody levels of all groups including immunized and nonimmunized animals increased significantly after viral challenge. In conclusion, the immune response induced by the experimental S and N polypeptide vaccines had no significant ability to prevent viral infection and pathogenicity in golden hamsters.

Tolerogenic dendritic cells pulsed with islet antigen induce long-term reduction in T-cell autoreactivity in type 1 diabetes patients.

Restoration of immune tolerance may halt progression of autoimmune diseases. Tolerogenic dendritic cells (tolDC) inhibit antigen-specific proinflammatory T-cells, generate antigen-specific regulatory T-cells and promote IL-10 production in-vitro, providing an appealing immunotherapy to intervene in autoimmune disease progression. A placebo-controlled, dose escalation phase 1 clinical trial in nine adult patients with long-standing type 1 diabetes (T1D) demonstrated the safety and feasibility of two (prime-boost) vaccinations with tolDC pulsed with a proinsulin peptide. Immunoregulatory effects were monitored by antigen-specific T-cell assays and flow and mass cytometry. The tolDC vaccine induced a profound and durable decline in pre-existing autoimmune responses to the vaccine peptide up to 3 years after therapy and temporary decline in CD4 and CD8+ T-cell responses to other islet autoantigens. While major leukocyte subsets remained stable, ICOS+CCR4+TIGIT+ Tregs and CD103+ tissue-resident and CCR6+ effector memory CD4+ T-cells increased in response to the first tolDC injection, the latter declining thereafter below baseline levels. Our data identify immune correlates of mechanistic efficacy of intradermally injected tolDC reducing proinsulin autoimmunity in T1D.

A career in cancer vaccines: exploring the promise of B cell epitopes

Roisin McGuigan, Editor,&#160;Immuno-Oncology Insights, speaks to Pravin TP Kaumaya, Professor and Director of Vaccine Research at The Ohio State UniversityPravin Kaumaya is Professor of Medicine in the Department of Ob/Gyn at the OSU Wexner Medical Center and the James Comprehensive Cancer Center. Dr Kaumaya is internationally recognized as an expert in the fields of vaccine research with emphasis on peptide vaccines for cancer. His work over three decades in developing B cell epitope-based cancer vaccines is a paradigm shift in the immune-oncology landscape. Dr Kaumaya is an elected fellow of the American Association for the Advancement of Science (AAAS), and he was elected as the treasurer of the American Peptide Society since 2009. He has lectured worldwide and has published over 130 peer-reviewed articles in major scientific journals. He conducts research in the areas of immune-oncology, tumor immunology, peptide design and immune mechanisms supported largely by NIH, Pelotonia and more recently by Imugene, Ltd. He is an inventor on several issued and pending patents for peptide cancer vaccines and immune-therapeutic technologies. Vaccines developed for HER-1, HER-3, IGF-1R and VEGF at the university has been licensed to IMUGENE Ltd. Dr Kaumaya has conducted two first man/woman NCI funded and FDA approved Phase 1 Trial in Cancer Patients (Stage four) with solid tumors in several indications (Breast, Ovarian, GIST) at the OSU James Cancer Hospital has recently been completed successfully demonstrating the safety and efficacy of the vaccine. Dr Kaumaya’s laboratory has recently developed a PD-1-Vaxx (programmed cell death) B cell peptide cancer vaccine that induces the body to produce polyclonal antibodies that block PD-1 signaling and produce an anticancer effect similar to the marketed immunotherapy drugs Keytruda&#174; and Opdivo&#174;.

Development of a Novel HTLV-1 Protease: Human Fcγ1 Recombinant Fusion Molecule in the CHO Eukaryotic Expression System.

Human T-cell leukaemia virus type 1 (HTLV-1) is the causative agent of two life-threatening diseases, adult T cell leukaemia/lymphoma (ATLL), and HTLV-1-associated myelopathy/tropical spastic (HAM/TSP). HTLV-1 protease (HTLV-1-PR) is an aspartic protease that represents a promising target for therapeutic purposes like human immunodeficiency virus-PR inhibitors (HIV-PR). Therefore, in this study, the human Fc fusion recombinant-PR (HTLV-1-PR:hFcγ1) was designed and expressed for two applications, finding a blocking substrate as a potential therapeutic or a potential subunit peptide vaccine. The PCR amplified DNA sequences encoding the HTLV-1-PR from the MT2-cell line using specific primers with restriction enzyme sites of Not1 and Xba1. The construct was then cloned to pTZ57R/T TA plasmid and, after confirming the PR sequence, subcloned into the pDR2ΔEF1α Fc-expression vector to create pDR2ΔEF1α.HTLV-1-PR:hFcγ1. The integrity of recombinant DNA was confirmed by sequencing to ensure that the engineered construct was in the frame. The recombinant fusion protein was then produced in the Chinese hamster ovary cell (CHO) system and was purified from its supernatant using HiTrap-rPA column affinity chromatography. Then, the immunofluorescence assay (IFA) co-localisation method showed that HTLV-1-PR:hFc recombinant fusion protein has appropriate folding as it binds to the anti-Fcγ antibody; the Fcγ1 tag participates to have HTLV-1-PR:hFcγ1 as a dimeric secretory protein. The development and production of HTLV-1-PR can be used to find a blocking substrate as a potential therapeutic molecule and apply it in an animal model to assess its immunogenicity and potential protection against HTLV-1 infection.

Abstract IA013: Intercepting pancreatic cancer development with mutant KRAS-targeted immunotherapy

Abstract The evolution of pancreatic ductal adenocarcinoma (PDAC) from tumor initiation to metastases requires years to decades, providing a window of opportunity for the prevention of premalignant progression. One of the first genetic mutations to occur early in development is in KRAS, an oncogene that is expressed by over 90% of PDACs. KRAS mutations (mKRAS) are attractive targets as they are recurrent hot–spot drivers that are expressed by, and drive the growth of all PDAC cells. Preclinical data provide compelling evidence that targeting mKRAS proteins using a Listeria-based vaccination approach in KPC mouse model results in prevention of progression from precursor lesions to PDAC. Based on these data, we hypothesize that targeting mKRAS in combination with bypassing early immune–suppressive signals will slow or even halt the progression of precursor lesions to PDA in subjects who are at high–risk. We have thus developed a clinical–grade long peptide vaccine targeting the six most common mKRAS proteins (G12V, G12R, G12A, G12C, G12D, and G13D) in PDAC patients. To establish initial safety and immunogenicity, our KRAS vaccine has been tested in 11 patients thus far in a Phase 1 clinical trial (NCT04117087) in combination with checkpoint blockade in patients who have undergone surgery and peri–operative chemotherapy and remained disease–free on imaging. Longitudinal immune data demonstrates an induction of activated and poly-functional mKRAS-specific CD4+ and CD8+ T cells, as well as effector and central memory T cells post–vaccination. In parallel, we performed paired single-cell RNA and TCR sequencing in PBMCs from a patient to obtain greater resolution of the vaccine–induced cytotoxic anti–tumor T cells. We captured 66,869 immune cells across three timepoints for analysis. Notably, we similarly observed an expansion of central memory CD4+ and CD8+ T cells post–vaccination. Using a novel computational algorithm (developed in collaboration with Dr. Elana Fertig’s lab) that takes into account physiochemical similarity of known mKRAS TCRs, we used our single–cell dataset to identify mKRAS-reactive TCRs` in the periphery that were functionally validated in vitro using CRISPR-Cas12a-based genome editing of human T cells. Overall, these studies suggest the induction of de novo, high quality mutant KRAS–specific T cells in the peripheral blood post–vaccination. Based on these immune data, we are enrolling onto a second clinical trial testing our mKRAS peptide vaccine in patients who are at high risk for developing PDAC (NCT05013216). These high-risk groups include those with strong family histories of PDAC or known pathogenic germline variants with a lifetime risk of up to 10% of developing PDA. Our preliminary data in our first three vaccinated patients shows an induction of mKRAS–specific T cell responses in the peripheral blood. Further studies characterizing the T cell response will lay the foundation for peripheral T cell–based biomarkers that could be used to predict response in a prevention setting. Citation Format: Neeha Zaidi, Amanda Huff, Emily Marcisak-Davis, Daniel Haldar, Thatcher Heumann, Max Konig, Brian Mog, Janelle Montagne, Gabriella Longway, Lalitya Andaloori, Melissa Lyman, Ludmila Danilova, Julie Nauroth, Luciane Kagohara, Elana Fertig, Nilo Azad, Elizabeth Jaffee. Intercepting pancreatic cancer development with mutant KRAS-targeted immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr IA013.

QLTI-23. BRAIN TUMOR-RELATED PAIN: INNOVATIVE APPROACHES TO DIAGNOSIS, TREATMENT, AND QUALITY OF LIFE ISSUES: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract OBJECTIVE The purpose of this systematic review and meta-analysis is to evaluate the various innovative approaches to diagnosing and treating patients presenting with brain tumor-related pain. BACKGROUND Brain tumors make up for lower than 2% of all cancers, which is heavily linked to high morbidity, deteriorated quality of life, and the death of the affected patients. Glioblastoma (GBM) makes up 38% of the malignant brain glioma.The main treatment approaches for gliomas are widely dependent on chemotherapy and radiation therapy. However, these methods have been associated with vast side effects which constitute the quality of life of the patient. METHODS This systematic review and meta-analysis conformed to PRISMA guidelines. A total of 3025 studies were assessed through the eligibility criteria to remain with twenty eligible studies. The included studies were then grouped into two categories; group one comprised 14 studies that focused on an innovative approach to diagnosis and treatment of gliomas, and six studies comprised of studies that focused on health-related quality of life (HRQoL) of patients with brain tumors. RESULTS Twenty studies that met the inclusion criteria were analyzed independently and in two groups: diagnosis and treatment and quality of life issues of brain tumor patients. In one group, one study revealed a relatively progression-free survival (PFS) going up to 57 weeks and overall survival (OS) time of more than 20 weeks after the initial surgery. Group two indicated HRQoL issues associated with symptoms such as headaches, fatigue, trauma, cognitive and personality dysfunction, leg weakness, and neurological deficits. CONCLUSION Timely diagnosis of the gliomas has significant improvements to the overall survival. Treatment approaches explored in the studies include Temozolomide (TZ), Gliadel Wafer, immunogeno-type, peptide vaccination, Bevacizumab, chemotherapy, radiation therapy, and Temsirolimus. Chemotherapy and radiation therapy have been linked to a deteriorated quality of life of the patients

CTIM-17. EO2401 THERAPEUTIC VACCINE FOR PATIENTS WITH RECURRENT GLIOBLASTOMA: PHASE 1/2 ROSALIE STUDY (NCT04116658)

Abstract EO2401 includes microbial-derived, synthetically produced HLA-A2 restricted peptides with molecular mimicry to antigens (IL13Rα2, BIRC5 and FOXM1) upregulated in glioblastoma, and the CD4 helper peptide UCP2. Patients with glioblastoma at first progression received EO2401 (300µg/peptide, q2weeks x4 then q4weeks), EO2401+nivolumab (3mg/kg q2weeks), or E02401+nivolumab+bevacizumab (10mg/kg q2weeks). Cohort-1 included EO2401x2 then EO2401+nivolumab. EO2401+nivolumab was evaluated in Cohort-2a, as adjuvant treatment in Cohort-2b, and as neoadjuvant/adjuvant treatment in Cohort-2c. Cohort-3 assessed EO2401+nivolumab+bevacizumab. Part 1 included 40 patients (Cohort-1/3, Cohort-2a/23, Cohort-2b/3, Cohort-3/11). Part 2 allowed low-dose-bevacizumab (5mg/kg q2weeks) for symptomatic edema and enrolled 38 patients (Cohort-1/18, Cohort-2a/15, Cohort-2b/3; and recruiting Cohort-2c/2 target 6, Cohort-3/0 target 15).Safety assessment of part 1 showed EO2401+nivolumab+/-bevacizumab to be well tolerated with EO2401 associated toxicity limited to local administration site reactions (48%; all grade 1-2). The nivolumab-/bevacizumab-toxicity was consistent with historical single-agent data. Strong CD8 T cell ELISPOT responses against the 3 vaccine peptides and cross-reactivity against targeted antigens was demonstrated in the majority of evaluable patients. Immune response was confirmed with tetramer staining of specific CD8 either ex vivo or after in vitro stimulation. For part 1, median progression-free survival (mPFS), and median survival (mOS) for EO2401+nivolumab (Cohorts-1/2/2b, n=29 median follow-up [mFU] 14.0 months) were 1.8 and 10.6 months. Patients on EO2401+nivolumab+bevacizumab (n = 11 mFU 9.6 m) had mPFS 5.5 months and 9 patients alive 7-12.4 months. Objective Response Rate/Disease Control Rate for EO2401+nivolumab and EO2401+nivolumab+bevacizumab was 10%/34% and 55%/82%.Median treatment duration for Cohort-2a part 1 was 6.1 weeks (1/23 on treatment), while it was 10.0 weeks (8/15 on treatment) for Cohort-2a part 2. Overall, in part 2, 36% received low-dose-bevacizumab.EO2401 generated strong immune responses and was well tolerated. Addition of standard bevacizumab to EO2401+nivolumab improved PFS and tumor response. Symptom driven low-dose-bevacizumab supported longer treatment durations. Outcome of study part 2 will be presented.

CTIM-22. THE COMBINATION OF LOMUSTINE AND THE IMMUNOCYTOKINE L19TNF IS A PROMISING TREATMENT FOR RECURRENT GLIOBLASTOMA

Abstract Glioblastoma is the most aggressive primary brain tumor and adults and poorly immunogenic. Treatment options for recurrent glioblastoma after standard of care chemoradiation are limited Several immunotherapeutic strategies including peptide vaccination and immune checkpoint inhibition have so far failed to improve survival and except from potentially regorafenib, no other agent has demonstrated superior activity to lomustine. Therefore, there is an urgent need for more effective treatment strategies for recurrent glioblastoma. Here, we investigate a new treatment combination based on the alkylating chemotherapy lomustine and the tumor-stroma targeting antibody-cytokine fusion protein L19TNF in preclinical glioma models and patients with recurrent glioblastoma. The combination treatment with lomustine and L19TNF demonstrated strong synergistic anti-tumor activity in several immunocompetent orthotopic glioma models curing the majority of tumor-bearing mice, whereas other mono- or combination therapies for example with anti-PD1 had only limited anti-glioma activity. Investigations of the mechanism of action revealed that lomustine plus L19TNF led to intratumoral necrosis, DNA damage and triggered a strong local anti-tumor immune response with increased MHC-I expression, presentation of neoepitopes and increased abundance of tumor-infiltrating lymphoid cells. In the first patients treated within a phase I/II clinical trial (NCT04573192), the treatment was well tolerated, and durable objective tumor responses and disease stabilizations could be observed also in patients with an unmethylated MGMT promoter.

Polymer-colloidal systems as MRI-detectable nanocarriers for peptide vaccine delivery

Diverse macromolecular delivery systems have been created to increase the stability and potency of peptide vaccines. However, many of them are insufficient in size and morphology to ensure efficient interaction between immunogens and immune cell receptors. Moreover, they are often released too slowly from the body after performing their desired function. To overcome these limitations, we have developed novel biocompatible polymer-colloidal carriers based on maghemite (γ-Fe2O3) nanoparticles coated with poly[N-(2-hydroxypropyl)methacrylamide] (p(HPMA)) polymers. Various types of p(HPMA) polymers (semitelechelic homopolymers, statistical copolymers and di-block copolymers) are attached to the surface of the γ-Fe2O3 particles via an iron-chelating deferoxamine group linked to the ends of their chains through stable or stimuli-responsive bonds. The resulting nanoparticles are stable and well-defined with negligible toxicity and of a suitable hydrodynamic size. They also feature a high number of binding sites for attaching peptide immunogens. Nanoparticles with polymers attached via reducible disulphide bonds exhibited rapid decoating upon incubation in the solutions, mimicking a reductive intracellular environment. In addition, we successfully conjugated a minimal peptide immunogen (V3) derived from the HIV-1 binding site to representative polymer-colloidal systems, demonstrating their suitability for vaccine delivery. Finally, the superparamagnetic properties of these nanoparticle vaccines enable their detection by MRI, which can be used to monitor biodistribution and pharmacokinetics.

Immunoinformatics Analysis of Citrullinated Antigen as Potential Multi-peptide Lung Cancer Vaccine Candidates for Indonesian Population.

Non-small-cell lung cancer (NSCLC) is the most common lung cancer which has the highest mortality rate in Indonesia. One of the trends in treating cancer is by utilizing peptide vaccines, an immunotherapeutic approach that aims to stimulate the cell-mediated adaptive immune system to recognize cancer-associated peptides. Currently, no peptide vaccines are available in the market for NSCLC treatment. Therefore, this project aims to develop a multi-epitope peptide-based vaccine for NSCLC utilizing citrullinated peptides. Citrullination is a post-translational modification that occurs in cancer cells during autophagy that functions to induce immune responses towards modified self-epitopes such as tumor cells, through activation of PAD enzymes within the APC and target cells. It was found that introducing a common citrullinated neo-antigen peptide such as vimentin and enolase to the immune system could stimulate a higher specific CD4+ T cell response against NSCLC. Moreover, carcinoembryonic antigen (CEA), an antigen that is highly expressed in cancer cells, is also added to increase the vaccine's specificity and to mobilize both CD4+ and CD8+ T cells. These antigens bind strongly to the MHC Class II alleles such as HLA-DRB1*07:01 and HLA-DRB*11:01, which are predominant alleles in Indonesian populations. Through in silico approach, the peptides generated from CEA, citrullinated vimentin and enolase, were analyzed for their MHC binding strength, immunogenicity, ability to induce IFNγ response, and population coverage. It is expected that the immunodominant antigens presentation is able to induce a potent immune response in NSCLC patients in Indonesia, resulting in tumor eradication.

The long multi-epitope peptide vaccine combined with adjuvants improved the therapeutic effects in a glioblastoma mouse model.

Emerging data have suggested that single short peptides have limited success as a cancer vaccine; however, extending the short peptides into longer multi-epitope peptides overcame the immune tolerance and induced an immune response. Moreover, the combination of adjuvants such as lenalidomide and anti-programmed cell death protein 1 (PD1) with a peptide vaccine showed potential vaccine effects in previous studies. Therefore, the effects of a long multi-epitope peptide vaccine in combination with lenalidomide and anti-PD1 were analyzed in this study. Long multi-epitope peptides from two MHCI peptides (BIRC597-104 and EphA2682-689) and the pan-human leukocyte antigen-DR isotype (HLA-DR) binding epitope (PADRE) were synthesized. The therapeutic effects of long multi-epitope peptides in combination with lenalidomide and anti-PD1 were confirmed in the murine GL261 intracranial glioma model. Immune cells' distribution and responses to the long multi-epitope peptides in combination with these adjuvants were also estimated in the spleens, lymph nodes, and tumor tissues. The difference between long multi-epitope peptides and a cocktail of multi-epitope peptides combined with lenalidomide and anti-PD1 was also clarified. As a result, long multi-epitope peptides combined with lenalidomide and anti-PD1 prolonged the survival of mice according to the suppression of tumor growth in an intracranial mouse model. While long multi-epitope peptides combined with these adjuvants enhanced the percentages of activated and memory effector CD8+ T cells, the increase in percentages of regulatory T cells (Tregs) was observed in a cocktail of multi-epitope peptides combined with lenalidomide and anti-PD1 group in the tumors. Long multi-epitope peptides combined with these adjuvants also enhanced the function of immune cells according to the enhanced pro-inflammatory cytokines and cytotoxicity against GL261 cells in ex vivo. In conclusion, long multi-epitope peptides composed of MHCI peptides, BIRC5 and EphA2, and the MHCII peptide, PADRE, in combination with lenalidomide and anti-PD1 has the potential to improve the therapeutic effects of a vaccine against GBM.

Peptide Cross-Linking Using Tyrosine Residues Facilitated by an Exogenous Nickel-Histidine Complex: A Facile Approach for Enhancing Vaccine-Specific Immunogenicity.

An improved method for the generation of peptide vaccines using di-tyrosine cross-linking is described. The conserved ion channel peptide, M2e, of influenza A virus was modified with the addition of small tyrosine-rich regions (GYGY-) at both the N- and C-termini and extensively cross-linked via tyrosine-tyrosine linkages to form peptide nanoclusters. The cross-linking was catalyzed using exogenous nickel(II) ions complexed to an exogenous glycine-glycine-histidine peptide in the presence of an oxidizer. Mice that were intranasally or intramuscularly immunized with the M2e-vaccine nanoclusters induced comparable levels of M2e-specific serum antibodies. Vaccination via the intranasal or intramuscular route protected mice from subsequent lethal challenge with an influenza A virus. In comparison to our previous approach, where a histidine-rich tag was added into the peptide structure, the use of exogenous histidine reduced irrelevant off-target immune response. Additionally, the purity of the resulting nanoclusters is an attractive feature, making this approach appealing for vaccine development.