MR1

Taking a significant leap in the field of vaccine development, Schulich School of Medicine & Dentistry researchers have discovered a potential 'super molecule' that can bolster the effectiveness of several vaccines against viral diseases, including influenza, COVID-19 and smallpox. Taking a significant leap in the field of vaccine development, Western researchers have discovered a potential 'super molecule' that can bolster the effectiveness of several vaccines against viral diseases, including influenza, COVID-19 and smallpox. A team led by Western professor Mansour Haeryfar found that a vitamin B2-derived molecule called 5-OP-RU, which is produced by bacteria, can enhance the efficacy of several vaccines for viral diseases. The study revealed the molecule binds to a protein called MR1 before stimulating a population of T lymphocytes called mucosa-associated invariant T (MAIT) cells -- essentially, one of the "first responders" that come rushing to fight off infection when a virus invades the body. The findings, recently published in PLOS Pathogens, could have significant implications for strengthening the global response to current and future viral threats. "We need better vaccines to combat viruses of pandemic potential, which are among the most vicious existential threats to human populations," said Haeryfar, professor of immunology at Western's Schulich School of Medicine & Dentistry. "Our strategy of targeting the MR1-MAIT cell axis using 5-OP-RU shows promise in generating strong antiviral immune responses in the body. This strategy could help develop more effective viral vaccines." For the study, the team of researchers used a combination of clinically relevant mouse models, human cell cultures and multiple vaccine platforms against various influenza, SARS-CoV-2 and smallpox. They found that 5-OP-RU worked in tandem with antiviral vaccines to expand MAIT cells and reprogram them to become more powerful antiviral entities. "MAIT cells are often found in the bloodstream and in mucosal tissues, including in our respiratory system, which is often the first place in which many viruses are encountered" said Haeryfar. When viruses like flu or SARS-CoV-2 get into our lungs, MAIT cells are already there and ready to fight. They respond quickly to infections, coordinate our immune response, and help destroy virus-infected cells. This makes them very attractive targets in vaccine design strategies." As for the next steps, Haeryfar and his team plan to extend their studies to test the efficacy of 5-OP-RU in several COVID vaccine candidates, including a promising Western-developed COVID-19 vaccine candidate and inhaled vaccines. "While mRNA vaccines were and remain potent in reducing the risk of severe morbidity and mortality due to COVID-19, we need more effective vaccines to prevent infection with SARS-CoV-2 variants of concern. We are now looking to investigate the possibility of using 5-OP-RU and potentially other MR1-binding molecules in inhaled vaccines," he added. The study also suggests that the unique characteristics of MAIT cells -- quick-acting entities with antibacterial and tissue repair properties -- could also help resolve secondary bacterial infections and tissue damage in the aftermath of viral infection. "It is also noteworthy that MAIT cells are evolutionarily conserved. Therefore, the results of preclinical studies are likely to be translatable to the clinic," said Haeryfar. "Everyone has the exact same MR1 protein. Therefore, immunization strategies that target MR1 and MAIT cells should work across diverse human populations, regardless of their genetic makeup." Supervised by Haeryfar, the study was spearheaded by Western graduate student Rasheduzzaman Rashu and a team of current and former Haeryfar Lab trainees including Marina Ninkov, Christine Wardell, Jenna Benoit, Nicole Wang and Courtney Meilleur. The research included contributions from Western professors David Hess, Stephen Barr, Ryan Troyer and Chil-Yong Kang, and researchers from McMaster University. This research was supported by a Canadian Institute of Health Research (CIHR) Project Grant awarded to Haeryfar.

--The molecules open the door for development of immunotherapies that are truly universal and work across HLA types, regardless of patient ancestry— PHILADELPHIA, June 13, 2023 /PRNewswire/ -- Class I major histocompatibility complex (MHC-I) proteins play an essential role in the immune system of all jawed vertebrates. The MHC-I displays peptide fragments of proteins from within the cell on the cell surface, "presenting" them to the immune system, which is constantly scanning the body for foreign or toxic antigens. When foreign peptides are identified, they trigger a cascade that allows cytotoxic T cells to eliminate intruders. This process has been exploited in the development of both vaccines and immunotherapy, wherein researchers identify fragments of peptides unique to viruses or cancer and then screen for T cells that recognize those targets and initiate an immune response. However, the current process of using MHC-I molecules as probes in vaccine and immunotherapy development is laborious. MHC-I molecules are extremely unstable, and making just one of these molecules can take a week, making it prohibitive to scan large libraries of peptides in an efficient manner. Now, researchers from Children's Hospital of Philadelphia (CHOP) have potentially solved this problem by engineering stable, universal MHC-I molecules that can be produced rapidly at scale, allowing researchers not only to develop vaccines and immunotherapies more quickly but also to identify molecules that can work broadly across the population. The findings were published today in the Proceedings of the National Academy of Sciences. "The findings in this paper have the potential to revolutionize this field, both in the way we manufacture these molecules and the rate at which we can screen for effective and universal immunotherapies," said senior author Nikolaos G. Sgourakis, PhD, Associate Professor in the Center for Computational and Genomic Medicine at Children's Hospital of Philadelphia. "We are no longer limited by the instability of these molecules and the long timeframe it used to take to manufacture them. These stabilized MHC-I molecules could speed up the screening process and the subsequent development of effective therapies." Led by Sgourakis Lab members Yi Sun, Michael C. Young, and Claire H. Woodward, the researchers stabilized MHC-I molecules by focusing on their 3D structure. Classical MHC-I molecules are comprised of three major parts: a peptide antigen consisting of 8 to 15 amino acids; a light chain that is the same for all MHC-I molecules; and a highly polymorphic heavy chain. In humans, the MHC-I is called human leukocyte antigen, or HLA, which has expanded because of constant evolutionary adaptation in the human population to include more than 35,000 variants, with a variety of different residues located on groove where peptides can bind. Because HLA is so polymorphic, different HLA types display different peptide repertoires, bind different molecular chaperones, and display different T cell receptors (TCRs), which ultimately define immune responses and disease susceptibility. Thus, finding universal targets and immunotherapies that work across the human population has been challenging. To stabilize MHC-I and make it useful for universal peptide loading and screening, the researchers focused on the light chain of the molecule, since it is conserved across HLA types. The light chain performs an important role in stabilizing MHC-I molecules. As soon as the light chain falls off, it triggers the MHC-I molecule to disassemble, at which point it is essentially sent for recycling for future peptide loading, serving as a sort of "on/off" switch for the MHC-I molecule. To exploit this fundamental engineering, the researchers tethered the heavy chain to the light chain, stabilizing the MHC-I in a conformation that is "open" and receptive to peptides. The researchers confirmed the stability of these engineered MHC-I molecules through biophysical characterization, using nuclear magnetic resonance (NMR), showing that their open MHC-I molecules have enhanced stability when loaded with peptides, even those of low to moderate affinity. The researchers also demonstrated that their engineered MHC-I molecules promote peptide exchange across multiple HLA allotypes, covering representatives from five HLA-A, six HLA-B supertypes, and HLA-Ib molecules, which have many different forms. A key component of using this system to enable a high-throughput peptide exchange platform was the design of customized "placeholder" peptides containing unnatural amino acid modifications, which was done in close collaboration with the lab of chemical biologist George Burslem, PhD, at the University of Pennsylvania. "The open MHC-I platform leverages minimal protein modifications to enhance ligand exchange reactions across all known HLA allotypes, as well as oligomorphic MR1 molecules which present aberrant metabolites that are associated with many tumors," Dr. Sgourakis said. "These new molecules could be a versatile tool for screening antigenic epitopes, enabling the detection of low-frequency receptors and engineered antibodies for the development of targeted therapies." This work was supported through grants by NIAID (5R01AI143997), NIDDK (5U01DK112217), and NIGMS (5R35GM125034 and R35GM142505). Additional support was provided through a Fox Chase Cancer Center pilot project grant and NIH grants P30CA006927 and T32GM132039. Sun Y, Young MC, Woodward CH, Danon JN, Truong HV, Gupta S, Winters TJ, Font-Burgada J, Burslem GM, and Sgourakis NG. "Universal open MHC-I molecules for rapid peptide loading and enhanced complex stability across HLA allotypes," Proceedings of the National Academy of Sciences, online June 13, 2023, DOI: 10.1073/pnas.2304055120. About Children's Hospital of Philadelphia: A non-profit, charitable organization, Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals, and pioneering major research initiatives, the 595-bed hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country. The institution has a well-established history of providing advanced pediatric care close to home through its CHOP Care Network, which includes more than 50 primary care practices, specialty care and surgical centers, urgent care centers, and community hospital alliances throughout Pennsylvania and New Jersey, as well as a new inpatient hospital with a dedicated pediatric emergency department in King of Prussia. In addition, its unique family-centered care and public service programs have brought Children's Hospital of Philadelphia recognition as a leading advocate for children and adolescents. For more information, visit . Contact: Dana Bate Children's Hospital of Philadelphia (267) 426-6055 [email protected] SOURCE Children's Hospital of Philadelphia

OXFORD, England, May 9, 2022 /PRNewswire/ -- Enara Bio, a biotechnology company advancing novel T-cell receptor (TCR) directed immunotherapies against unconventional, shared, cancer-specific antigens, today announces that three abstracts from the Company and its academic collaborators have been selected for presentation at the 12th International CD1-MR1 European Molecular Biology Organization (EMBO) Meeting, which will be held in Gothenberg, Sweden, 22-26 May 2022. The three abstracts cover pioneering research being conducted by Enara Bio in collaboration with leading immunology and MR1 research groups at Monash University and the University of Oxford towards the identification and validation of cancer-specific MR1 ligands and the development of MR1-targeted T-cell receptor cell therapies (TCR-T). MR1 is an unconventional antigen-presenting molecule that presents metabolites to the immune system in the context of cancer and infection. The monomorphic nature of MR1 strongly suggests that therapies based on MR1-displayed antigens could be effective across the entire human population. These unique properties make MR1 a promising target for off-the-shelf, HLA-independent, TCR-based immunotherapies for solid tumors. The first presentation, from Enara scientists, highlights the progress the Company is making with its lead autologous MR1-targeting TCR-T program. The two other presentations, led by scientists from Jamie Rossjohn's and Tony Purcell's groups at the Monash Biomedicine Discovery Institute (BDI), and Nicola Ternette's group at the University of Oxford's Nuffield Department of Medicine, describe novel immunopeptidomic and metabolomic methods to identify and characterize the cancer-specific MR1 ligandome. Joe Dukes, Vice President, Head of Research at Enara Bio, commented: "We are very pleased to be presenting important abstracts at the upcoming CD1-MR1 EMBO meeting, which showcase the continued developments we are making in partnership with our world-class collaborators to advance the next generation of cancer immunotherapies designed to treat a broad patient population. We have made remarkable progress in our mission to characterize unconventional immunotherapy targets, such as ligands presented by MR1, which we hope will enable development of a pipeline of product candidates that can be advanced into clinical development." Details of the poster presentations (which will be available on the Company website at the time of the meeting) are as follows: Enara Bio - Abstract Title: A novel TCR-T cell therapy targeting a cancer-specific antigen presented by monomorphic MR1 to overcome the challenge of HLA restricted TCR therapies. - Presenter: Dr. Jonathan Silk Monash University - Abstract Title: Design and testing of cleavable constructs for identification and functional validation of MR1 ligands. - Presenter: Dr. Patricia Illing The University of Oxford - Abstract Title: Development of a metabolomics-based MR1 ligand discovery platform using proteomics instrumentation - Presenter: Dr. Thierry Schmidlin