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Wistar Scientists Engineer New NK cell Engaging Immunotherapy Approaches to Target and potentially Treat recalcitrant Ovarian Cancer

PHILADELPHIA—(Nov. 1, 2023)— The Wistar Institute’s David B. Weiner, Ph.D., executive vice president, director of the Vaccine & Immunotherapy Center (VIC) and W.W. Smith Charitable Trust Distinguished Professor in Cancer Research, and collaborators, have engineered novel monoclonal antibodies that engage Natural Killer cells through a unique surface receptor that activates the immune system to fight against cancer.

In their publication titled, “Siglec-7 glyco-immune binding MAbs or NK cell engager biologics induce potent anti-tumor immunity against ovarian cancers,” published in Science Advances, the team demonstrates the preclinical feasibility of utilizing these new cancer immunotherapeutic approaches against diverse ovarian cancer types, including treatment-resistant and refractory ovarian cancers — alone or in combination with checkpoint inhibitor treatment.

The research started as a collaboration between Wistar’s Drs. Weiner and Mohamed Abdel-Mohsen, who were exploring the development of new glyco-signaling biologic tools that may be important in the fight against cancer.

Ovarian cancer (OC) is frequently diagnosed late in the disease process, and OC resistance to currently available treatments make it especially problematic; according to the NIH, the chances of someone diagnosed with OC and surviving for five years is around fifty-fifty. Ovarian cancer demonstrates a low response rate to standard-of-care treatments like chemotherapies, PARP inhibitors and the widely used checkpoint inhibitor, PD-1.

In the small proportion of ovarian cancer patients that do respond to these treatments, resistance becomes problematic over time — resulting in tumor escape and cancer progression. Genetic mutations, such as the well-known BRCA gene mutations, predispose women to a high risk of progressive OC. The CDC expects more than thirteen thousand women to die of ovarian cancer this year in the U.S. alone.

To combat ovarian cancer treatment resistance, the team hypothesized that they might be able to engage not only the traditional T cell immune arm of the immune system which PD-1 and known checkpoint inhibitors (CPI) activate, but also implement a strategy to activate Natural killer cells (NK cells), a subset of important anti-tumor immune cells, through a conserved glyco-immune marker found on the surface of most NK cells called Siglec-7 (Sialic acid-binding immunoglobulin-type lectin). NK cells have been recently described to express Siglec-7, so the team tested two new strategies to engage and activate NK cells against ovarian cancer through Siglec-7.

The first approach used human monoclonal antibodies (mAb) discovered and developed at Wistar and novel assays to visualize and demonstrate that certain anti-Siglec-7 mAbs could activate human NK cells — which, in the presence of the antibodies, responded against multiple human OC cell lines. These now-activated NK cells would kill OC but not non-cancer cells with the Siglec-7 mAb treatment.

The researchers demonstrated that multiple OC carrying mutations, including BRCA1 and BRCA2, could be targeted by Siglec-7 antibodies through activated NK cells. The group moved to study the treatment of OC in a humanized mouse model and observed that the Siglec-7 treatment could impact OC growth slowing the tumors and increasing the animals’ survival.

Having demonstrated the feasibility of utilizing a Siglec-7 mAb in OC models, the team thought there were additional ways to use the Siglec-7 mAb to further focus on OC disease. They hypothesized that directly fusing the Siglec-7 reactive binding site of the Siglec-7 mAb to a second mAb that uniquely binds late OC through a molecule named Follicle Stimulating Hormone receptor (FSHR), which they had previously developed, would create a targeted Siglec-7 bispecific antibody that could bind through two distinct targets creating a new class of NK cell engagers (NKCE).

The team sought to test whether this Siglec-7 NKCE approach would be effective through the direct linkage of potentially killer NK cells to a guided missile aimed specifically at OC, which would open up a new path to develop additional Siglec-7 based immunotherapeutic approaches. In both bench and humanized mouse challenge studies, the Siglec-7-NKCE was effective at targeting OC, activating NK cells in local proximity and efficiently killing multiple OC.

Both Siglec-7 technologies (mAbs and NKCEs) demonstrated an ability to recruit and activate the NK cell population, shrink tumors and prolong survival in the models studied. The observation of on-target specificity of the approaches suggests that cancer’s apparent Siglec vulnerability can be exploited therapeutically, perhaps with limited toxicity — a promising sign for the future of anti-cancer Siglec research, but the team cautions that more work in this regard is important.

In an additional set of preliminary studies, the team also found that this Siglec-7 approach could complement PD-1 checkpoint inhibitor (CPI) therapy. This is an important area of further study that could uncover more details of the mechanisms involved and possibly extend the utility of such CPI in OC and, potentially, other cancers. “These findings open the door to further exploration of how we can engineer Siglec-7 immunotherapies and perhaps other related molecules for ovarian cancer and perhaps a larger group of recalcitrant cancers,” stated Dr. David B. Weiner, adding, “Further studies may bring such approaches as described to represent new tools in our antitumor toolbelt.”

As always, more research is needed to refine these technologies further on the long journey from the lab bench to the clinic. But this paper offers a different avenue for attempting to exploit these unique interactions of immune surface molecules such as Siglec-7 and perhaps other Siglecs.

“We have observed not one but two methods that can target NK cells in an effort to control ovarian cancer in both Petri dishes and in vivo models,” said Dr. Devivasha Bordoloi, the first author on the paper. “This research shows a lot of promise, and I’m excited to move these studies to the next steps.”

Co-authors: Devivasha Bordoloi, Abhijeet J. Kulkarni, Opeyemi S. Adeniji, Pratik S. Bhojnagarwala, Shushu Zhao, Candice Ionescu, Alfredo Perales-Puchalt, Elizabeth M Parzych, Xizhou Zhu, Ali R. Ali, Joel Cassel, Rugang Zhang, Mohamed Abdel-Mohsen and David B. Weiner of The Wistar Institute; and M. Betina Pampena and Michael R. Betts of Perelman School of Medicine, University of Pennsylvania,

Work supported by: Department of Defense Ovarian Cancer Research Program award W81XWH-19-1-0189; the W.W. Smith Charitable Trust Professorship in Cancer Research; and the Wistar Science Accelerator Postdoctoral Fellowship.

Publication information: “Siglec-7 glyco-immune binding MAbs or NK cell engager biologics induce potent anti-tumor immunity against ovarian cancers,” from Science Advances.

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The Wistar Institute, the first independent, nonprofit biomedical research institute in the United States, marshals the talents of an international team of outstanding scientists through a culture of biomedical collaboration and innovation. Wistar scientists are focused on solving some of the world’s most challenging and important problems in the field of cancer, infectious disease, and immunology. Wistar has been producing groundbreaking advances in world health for more than a century, consistent with its legacy of leadership in biomedical research and a track record of life-saving contributions in immunology and cell biology. wistar.org.

Wistar Scientists Successfully Engineer a Goldilocks Construct: Therapeutic Antibody Could Be a Future Medicine to Improve Outcomes for Melanoma

In recent years, multimodal therapies have emerged as a route to treat cancer by delivering different types of treatments together to improve effectiveness. However, the more modalities there are, the more complex the production and effects of these lifesaving treatments can become.

Wistar researchers have engineered a linked molecule that enables a three-modality therapy for treating melanoma. They accomplished this by connecting a cytokine and an antibody—which would ordinarily be administered separately—and then engineering a form that was pro-inflammatory enough to fight the cancer cells but not so inflammatory as to cause complications or reduce survival outcomes, according to a recently published study in Frontiers in Immunology.

“We took aspects of a cancer treatment regimen and tried to simplify that by combining antibody and cytokine together,” said Nicholas Tursi, the lead author on the study and a graduate student researcher in the lab of Dr. David Weiner, executive vice president, director of the Vaccine & Immunotherapy Center, and W.W. Smith Charitable Trust Distinguished Professor at The Wistar Institute. “I focused on engineering an intermediate cytokine that is efficacious but also has an acceptable pro-inflammatory profile—a Goldilocks approach.”

The engineered “Goldilocks” cytokine Tursi and his colleagues, including Dr. Weiner and Dr. Daniel Kulp, Associate professor in Wistar’s Vaccine & Immunotherapy Center, engineered to test their antibody cytokine chimera was called HL2-KOA1, a modified designer version of the T cell growth factor IL-2. This engineered molecule used in a combination therapeutic regimen was effective at promoting survival in a rigorous melanoma model.

“What this suggests is that we could use other antibodies or cytokines to engineer the immune response to further extend efficacy,” said Tursi. He is hopeful that this research will serve as the foundation for developing other antibody cytokine chimeras that work for melanoma and potentially other cancers.

Up in (Antibody) Arms: Synthetic DNA Immunotherapy Platform Combats Brain Cancer

Researchers in the Weiner Lab developed DNA-launched bispecific T cell engagers that controlled tumor growth and improved survival in glioblastoma.

Glioblastoma is one of the most severe and aggressive forms of brain cancer with limited treatment options and low survival rates. Wistar’s Weiner Lab is focused on creating new treatments to improve the patient’s quality of life and increase the opportunity to beat this difficult-to-treat cancer.

What approach is Dr. Weiner and his research team taking to tackle glioblastoma?

Dr. Weiner and his team are focused on dBTE’s – a synthetic DNA antibody platform for developing new T cell-redirecting immunotherapies. These immunotherapies deliver a lethal hit against diverse and difficult to-treat solid tumors.

The Weiner lab used genetic engineering combined with direct in vivo expression to create a novel dBTE which targets an important receptor on the surface of cells that initiate glioblastoma tumors. Approximately 75% of individuals with glioblastoma have a very specific receptor referred to as IL-13Ralpha2. The proof-of-concept study of IL-13Ralpha2 dBTEs on controlling glioblastoma was recently published in Molecular Therapy-Oncolytics.

“Glioblastoma is a severe disease with limited therapeutic options so the creation of novel and potentially more impactful therapeutic options for cancer patients such as the anti-glioblastoma dBTE is a major focus of Wistar’s Vaccine and Immunotherapy Center,” says David Weiner, Ph.D., executive vice president, director of the Vaccine & Immunotherapy Center, and W.W. Smith Charitable Trust Professor in Cancer Research.

Bispecific T cell engagers are synthetic antibodies with two chains or “arms” that can simultaneously bind an antigen expressed on a tumor and an antigen on a T cell and bring them closer together, triggering immune activation to protect the body from disease. “This redirects the activity of the T cell towards the tumor cell, attacking and killing the tumor.” explains Pratik Bhojnagarwala, graduate student in the Weiner lab and first author on the paper.

Challenges with conventional BTE treatments for cancer patients include the need for continuous IV injection over several weeks, costly treatment, and unwanted off-target issues. In this work, the team used synthetic DNA technologies to design, test and identify multiple synthetic DNA BTE forms having the most specific and potent killing activity against different glioblastoma human cancer cell lines.

It is this specific design combined with the dBTE approach that creates a kind of dBTE factory for the patient, enabling the consistent force and effectiveness of the therapy. Using this new anti-glioblastoma dBTE and direct nucleic acid encoded delivery, the researchers were able to more than double half-life of the bispecific antibodies in animal models – resulting in the clearing of tumors in vivo.

Dr. Weiner is also a leader in the development of another antibody based technology called DNA encoded monoclonal antibodies (dMAB) for treating infectious diseases including COVID-19, Zika, Ebola, and cancer. The biggest difference between dMABs and dBTEs is that dMABs encode for monoclonal antibodies that bind to a single target. DBTEs are designed to bind to two different targets at the same time and are more commonly used to engage the immune system to fight cancers. By innovating multiple types of platforms, the Weiner lab is on the forefront of translational studies harnessing basic science to fight difficult human diseases.

Bhojnagarwala plans to continue developing combination novel immunotherapies for cancer and infectious disease, specifically exploring additional designs for dBTE that can improve specificity and potency of the new approach and applying his studies towards targeting more tumor antigens for glioblastoma. He shares, “It is important for me to work in a lab where there is a high possibility that the work can rapidly be translated into clinical trials. The Weiner lab provides that platform.”

A Wistar Journey Through the Past, Present, and Future of Immunization Work

Vaccines are a crucial public health tool in its’ arsenal against diseases. Resurgences of diseases long thought eradicated are popping up decades later in sewage waters here and abroad, and we’ve witnessed what the impact of war has on countries whose health systems have crumbled under the ravages of war—we are not as far removed as we’d like to be from diseases once prevented by vaccines. With more than half a century of basic research for vaccine development, The Wistar Institute plays an integral role in immunization around the globe.

Rubella, rabies, and rotavirus. Wistar scientists developed vaccines for these diseases that are used in immunization programs worldwide. The rubella vaccine by Wistar scientists effectively ended the pandemic in the United States, as declared by the CDC in 2005. Two rabies vaccinations developed from the Institute addresses the disease in both animals and humans. In 2006, Wistar and collaborators created a rotavirus vaccine which became part of the regular immunization schedule for U.S. babies and is used or approved in over 45 countries. And we’re just getting started.

“Immunization is possibly one of the most impactful medical interventions ever developed. Millions of lives are saved each year by vaccination, and we live healthier and longer lives due to vaccines.” states David Weiner, Ph.D., Executive Vice President, Director of Wistar’s Vaccine & Immunotherapy Center, and W.W. Smith Charitable Trust Professor in Cancer Research, in the Immunology, Microenvironment & Metastasis Program at Wistar’s Ellen and Ronald Caplan Cancer Center.

This National Immunization Awareness Month, we have shared a few snapshots of current vaccine development projects at the Institute as well as what these researchers’ hopes are for the future of immunization.

Tackling Both Infectious Disease and Cancer with Immunization

Dr. Weiner’s research takes on both infectious disease and cancer. His work encompasses developing new ways to build and deliver synthetic nucleic acid vaccines – particularly advancing a new approach that drives self-assembly of an antigen into a more potent vaccine inside a vaccinated person. This approach gives the body the genetic information to become the factory to create the vaccine. Furthermore, his lab is developing new types of cancer therapeutic vaccines with the goals of creating strong anti-cancer immunity and eradicating cancer cells.

Weiner’s collaborations with public and private institutions is centered around novel immunization technology developed from his lab called DNA-encoded monoclonal antibodies (DMAbs) against diseases such as COVID-19, Zika, and Ebola.

Regarding the future, he shares, “Together with our collaborators, we hope to move new prototype HIV vaccines into human clinical trials later this year, and continue to advance vaccines for emerging pathogens, as well as cancer immunotherapies.”

Developing DNA Vaccines

Ami Patel, Ph.D., Caspar Wistar Fellow in the Vaccine and Immunotherapy Center, focuses her scientific efforts on DNA vaccines which have potential to be more stable and economical over traditional vaccine production. “We are trying to understand how different vaccines work in the body. How do vaccines generate different types of immune responses and can we use this to understand protection against infectious diseases. We are using this information to help develop the next generation of potential vaccines.” she says.

Patel emphasizes the importance of vaccines for young children and adults by calling back to various infectious diseases like polio that are no longer very common because of immunization. “Vaccines help protect us against serious disease. Some of us remember the discomfort of chicken pox as children. There is now a vaccine.”

While she calls the COVID-19 pandemic “devastating to global health”, Patel also recognizes the pandemic’s challenges proved fertile ground for an extraordinary collaborative time for biomedical scientists. “My hope is for vaccine researchers across different disciplines to continue to work together to help us understand different infectious diseases and develop better vaccines.”

Zooming in on a Nanoscale

In collaboration with Weiner, Daniel Kulp, Ph.D., associate professor in the Vaccine and Immunotherapy Center, has embraced nanotechnology in his vaccine research. “We are developing rationally engineered nanoparticle vaccines that can elicit extremely broad coronavirus immunity providing a proof-of-concept that a pan-coronavirus vaccine is possible,” Kulp elaborates.

While the Kulp laboratory is developing several promising vaccines, he emphasizes that his goal is to assess these candidates in humans. He says, “We are working to reduce barriers for launching small experimental medicine clinical trials allowing for broader evaluation of our best vaccine concepts. Through this type of work, I have high hopes that our generation can claim credit for the eradication of SARS-CoV-2.”

Kulp expresses that “Vaccines are one of the single most effective medical technologies humans have developed saving hundreds of millions of lives. Vaccines do not work without immunizations. This message is incredibly important.”

Collaboration Advances DNA-delivered Antibodies to Prevent COVID-19

PHILADELPHIA — (July 7, 2022) — Under a Defense Advanced Research Projects Agency (DARPA) and Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND) funded program, a novel COVID-19 antibody delivery approach has advanced to clinical trials. The collaborative team was led by David Weiner, Ph.D., The Wistar Institute executive vice president, director of the Vaccine & Immunotherapy Center, and W.W. Smith Charitable Trust Professor in Cancer Research, and included colleagues at the University of Pennsylvania, AstraZeneca, INOVIO Pharmaceuticals, and Indiana University.

This team was awarded $37.6 million to fund the rapid pre-clinical development of DNA-encoded SARs-CoV-2 monoclonal antibodies (DMAbs) to prevent COVID-19. DMAbs use a person’s own cells as a factory for making the protective antibodies, simplifying the development and the production process for biologics—which could broaden the use of such novel medicines to the global community.

The first dosing with this new investigational agent occurred in a first-in-human clinical trial being led by Pablo Tebas, M.D., professor of Infectious Diseases at the Perelman School of Medicine at the University of Pennsylvania, and his team. The clinical trial will assess the overall safety and tolerability of this novel approach to enable the body to produce multiple full-length monoclonal antibodies through advanced DNA technology in people.

“This development is the culmination of the many steps taken working together with our DARPA/JPEO leadership team and members of the consortium advancing this product at this important time. We look forward to seeing the initial outcome from this first-in-human clinical trial studying this novel concept,” Weiner shares. He elaborates on the goals of the trials, explaining “In addition to assessing safety and tolerability, we will also look for important insights into biological expression and activity in our trial subjects and if these can be shown to impact viral infection.”

“Despite all of the progress made on COVID-19 treatments and management, this disease continues to kill three times more Americans than the flu,” says Tebas. “We need better methods to prevent complications of this disease particularly in immunocompromised patients. Our study will test a new way to deliver antibodies against COVID-19 that have been proven to decrease hospitalizations and deaths from this terrible disease.”

This work is enabled through a unique public-private collaboration. The team brings together important and diverse scientific and technical strengths to create this new tool to address vulnerable patient needs. Over the past several years, Weiner and collaborators’ advances in the nucleic acid delivery space led to the developments that underpin this program. The study takes advantage of pioneering nucleic acid approaches advanced by longtime collaborator Tebas, important new tools for nucleic acid delivery developed in concert with INOVIO and is built on the collaboration with AstraZeneca to recreate protein biologics into this innovative DNA medicine approach.

Mark Esser, vice president, Early Vaccines and Immune Therapies, AstraZeneca, said, “Dosing the first patient with a COVID-19 DMAb candidate is the culmination of hard work from a collaborative public-private partnership. This trial provides an important opportunity to evaluate an innovative technology that could potentially transform how we deliver antibodies and protect against severe infections.”

The novel approach utilizes the genetic blueprints for antibodies encoded into DNA plasmids. After delivery into the arm, DMAbs instruct the body to assemble functional antibodies and secrete these into the blood as fully formed specific monoclonal antibodies against pathogens such as the SARS-CoV-2 virus. This approach bypasses the need for immunization to generate protective immunity.

Weiner says, “This project is an important example of team science and the value of working together to tackle difficult problems. The team’s mission was to advance and study a new way to deliver lifesaving therapies in a short time frame. We are hopeful that this clinical study will likely offer insight into the development of new therapeutic approaches for vulnerable patients.”

Together, the research collaboration has successfully shown evidence of SARS-CoV-2 protection in both laboratory and animal model studies with the DMAbs exhibiting the potential for both prevention and treatment of infection. In theory, this nucleic acid medicine approach has potential advantages when compared to traditional methods of monoclonal antibody treatment in aspects of cost, specificity, production, storage, and delivery, thus boosting its availability to patients more globally.

INOVIO Pharmaceuticals Chief scientific officer Laurent Humeau, Ph.D., says, “Advancing this human clinical study was made possible through the dedication of all parties involved in this consortium. We look forward to continuing to develop this promising monoclonal antibody delivery platform with our collaborators.”

This work is supported by the Office of the Assistant Secretary of Defense for Health Affairs with funding from the Defense Health Agency.

This research was developed with funding from the Defense Advanced Research Projects Agency (DARPA).

Disclaimer: The views, opinions and/or findings expressed are those of the author and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government.

Grant information: Synthetic DNA-encoded monoclonal antibodies (DMAbs) targeting COVID-19, 2020-2022, Contract #HR0011-21-9-0001.

Approved for Public Release, Distribution Unlimited

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The Wistar Institute is an international leader in biomedical research with special expertise in cancer research and vaccine development. Founded in 1892 as the first independent nonprofit biomedical research institute in the United States, Wistar has held the prestigious Cancer Center designation from the National Cancer Institute since 1972. The Institute works actively to ensure that research advances move from the laboratory to the clinic as quickly as possible. wistar.org

Highlighting Vaccine Research at The Wistar Institute Through the Penn-CHOP-Wistar Vaccine Symposium

From HIV to COVID-19, Wistar scientists are at the forefront of vaccine development. Read our recap of the recent Vaccine Symposium and the impactful research in progress at the Institute.

This past Monday, The Wistar Institute, University of Pennsylvania Perelman School of Medicine, and Children’s Hospital of Philadelphia held the Penn-CHOP-Wistar Vaccine Symposium. Hosted both in-person at the Smilow Center for Translational Research and online, the all-day event covered the history of vaccines and current vaccine research from the three sponsoring institutions.

Keynote speaker and Wistar professor emeritus Stanley Plotkin, M.D., is a prominent researcher who is known for the development of the rubella vaccine while he was a virologist at The Wistar Institute. Furthermore, his years of work helping in vaccine efforts for rabies, rotavirus, and cytomegalovirus have stimulated much innovation in the biomedical research community.
After giving a brief history of vaccines, Plotkin proclaimed “Vaccinology has taken off. … We are now in a golden age of vaccinology.”

The Symposium’s research presentations opened with Wistar’s Daniel Kulp, Ph.D., Associate Professor in the Vaccine & Immunotherapy Center, and his work on a novel COVID-19 nanoparticle vaccine. Amelia Escolano, Ph.D., Assistant Professor in the Vaccine & Immunotherapy Center, also spoke about her efforts investigating immunization strategies for HIV. Wistar’s Vaccine & Immunotherapy Center Director David B. Weiner, Ph.D., gave a summary of his research into the genetic delivery of vaccines, calling the innovation of vaccinology in Pennsylvania among these institutions “extraordinary”.

The current global pandemic has reinforced the need for scientific solutions and a deeper understanding of human diseases. It is the studies and ideas from research centers like The Wistar Institute and its colleagues that propel forward biomedicine. As keynote speaker Plotkin stated, “Pandemics have occurred throughout the history of humankind and will continue to do so in the future. Infectious diseases of humans will continue to happen. Therefore, we must act against them.”

Wistar Study Opens the Door to Faster, Cheaper HIV Vaccine Research

For the first time, scientists have developed an DNA-encoded immunogen that produces Tier-2 antibodies—the kind that matter for combatting HIV

Nearly four decades after its discovery, HIV has killed 36.3 million people, with no vaccine in sight. Part of the reason vaccine development has been slow is because trialing candidate vaccines that produce Tier-2 neutralizing antibodies—the kind that matter for combatting HIV—has always required long and expensive experiments in large animal models like rabbits and macaque monkeys.

An effective HIV vaccine needs to produce antibodies that protect against the most common variants of HIV, which are categorized as “Tier 2” viruses based on how quickly and easily they can be neutralized by antibodies (more quickly/easily than Tier 3, less than Tier 1).

A new study by scientists at The Wistar Institute shows a quicker, less expensive path to developing this tier of antibodies. For the first time, these scientists have demonstrated a method for eliciting Tier-2 neutralizing antibodies in mice.

“Mice are the workhorse of vaccine design and development because you can iterate lots of concepts in that model due to cost and time constraints,” said Daniel Kulp, Ph.D., associate professor in the Vaccine & Immunotherapy Center at The Wistar Institute.

The scientists developed an immunogen—a substance that causes an immune response—called a native-like trimer, which they administered to mice. Importantly, they encoded the immunogen in DNA, which turns the host bodies (in this case the mice) into “antigen factories” instead of requiring what would otherwise be a complex and expensive vaccine manufacturing process.

They then compared the results from the mice who received the DNA-encoded native-like trimer to results from mice who received a standard protein immunization. Only those mice that received the DNA-encoded native-like trimer developed Tier-2 neutralizing antibodies.

From there, they were able to isolate and examine the atomic structure of one of the antibodies that their immunogen had produced. “The structure gives us incredible insight into how this antibody is able to neutralize the virus,” said Kulp.

“Our data demonstrates the value of this approach as a tool to create surgically tailored immunity against a difficult pathogen’s vulnerable sites, in this case for HIV,” said coauthor David B. Weiner, Ph.D., executive vice president and director of the Vaccine & Immunotherapy Center and the W.W. Smith Charitable Trust Professor in Cancer Research at The Wistar Institute.

Wistar Scientists Move HIV Vaccine Research Forward by Developing an Immunogen that Produces Tier-2 Antibodies—the Kind That Matter for Combatting HIV

PHILADELPHIA — (Feb. 4, 2022) — Nearly four decades after its discovery, HIV has killed 36.3 million people, with no vaccine in sight. However, a new study by researchers at The Wistar Institute, an international biomedical research leader in cancer, immunology, infectious disease, and vaccine development, takes a promising step in the direction of developing an HIV vaccine.

The findings, published in Nature Communications, demonstrate the promise of using a unique native-like trimer to develop Tier-2 neutralizing antibodies—the kind that matter for combatting HIV—in mice for the first time.

Previously, eliciting these types of antibodies using candidate vaccines required long and expensive experiments in large animal models creating a significant bottleneck on HIV-1 vaccine development. “With our new finding, we have opened the door to rapid, iterative vaccinology in a model that can produce Tier-2 neutralizing antibodies, enabling development of more advanced HIV vaccine concepts,” said Daniel Kulp, Ph.D., associate professor in the Vaccine & Immunotherapy Center at The Wistar Institute and corresponding author on the paper.

The researchers encoded the native-like trimer into DNA for delivery into the mice. This has the practical advantage of turning the host bodies into “antigen factories” instead of requiring what would otherwise be a complex vaccine manufacturing process. The researchers then compared the results from the mice who received the DNA-encoded native-like trimer to results from mice who received a standard protein immunization. Only those mice that received the DNA-encoded native-like trimer developed Tier-2 neutralizing antibodies.

“We were able to generate strong immune responses with both platforms, but the DNA platform uniquely drove this neutralizing response,” said Kulp.

Once they’d verified their immunization regime was producing Tier-2 antibodies, Kulp and his colleagues isolated monoclonal antibodies from the mice and used cryo-electron microscopy to determine the atomic structure of one Tier-2 neutralizing monoclonal antibody. They found that the antibody binds to an epitope (a segment of a protein that sticks out of the antigen, which prompts an immune response) called C3V5. In the gold standard HIV vaccine model (non-human primates), prior research has shown that antibodies binding to C3V5 protect animals from a SHIV infection, which is a close relative of HIV that infects non-human primates.

“The structure gives us incredible insight into how this antibody is able to neutralize the virus,” said Kulp. “For the first time, we can strategize about how to design new vaccines that can generate broadly neutralizing antibody responses to the C3V5 epitope.”

Coauthor David B. Weiner, Ph.D., executive vice president and director of the Vaccine & Immunotherapy Center and the W.W. Smith Charitable Trust Professor in Cancer Research at The Wistar Institute, emphasized the utility of their findings.

“What we’ve done is enable direct in vivo self-assembly of structurally designed immunogens, which are engineered and delivered using nucleic acid technology, inside the vaccinated animal. Our data demonstrating induction of autologous Tier 2 neutralization illustrate the value of this approach as a tool to create surgically tailored immunity against a difficult pathogen’s vulnerable sites, in this case for HIV.”

Co-authors: Ziyang Xu, Susanne Walker, Neethu Chokkalingam, Mansi Purwar, Edgar Tello-Ruiz, Yuanhan Wu, Sonali Majumdar, Kylie M. Konrath, Abhijeet Kulkarni, Nicholas J. Tursi, Faraz I. Zaidi, Emma L. Reuschel, Ishaan Patel, April Obeirne, David B. Weiner, and Daniel W. Kulp from The Wistar Institute; Megan C. Wise, Katherine Schultheis, Lauren Gites, Trevor Smith, Janess Mendoza, Kate E. Broderick, and Laurent Humeau from Inovio Pharmaceuticals; Alan Moore, Jianqiu Du, and Jesper Pallesen from Indiana University.

Work supported by: National Health Institutes (NIH) IPCAVD Grant U19 Al109646-04; W. W. Smith Charitable Trust; and Wistar Monica H.M. Shander Memorial Fellowship.

Publication information: Induction of Tier-2 Neutralizing Antibodies in Mice with a DNA-encoded HIV Envelope Native Like Trimer, Nature Communications, 2022. Online publication.

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The Wistar Institute is an international leader in biomedical research with special expertise in cancer research and vaccine development. Founded in 1892 as the first independent nonprofit biomedical research institute in the United States, Wistar has held the prestigious Cancer Center designation from the National Cancer Institute since 1972. The Institute works actively to ensure that research advances move from the laboratory to the clinic as quickly as possible. wistar.org.

Novel Nanoparticle SARS-CoV-2 Vaccine Combines Immune Focusing and Self-assembling Nanoparticles to Elicit More Potent Protection

PHILADELPHIA — (Feb. 1, 2022) — The first generation of COVID-19 vaccines have been highly effective, but also have limitations: their efficacy can wane without a booster shot, and they may be less effective against some variants. Now scientists at The Wistar Institute have developed a more targeted vaccine that, in animal studies, shows stronger, broader, and more durable protection in a single, low dose.

The vaccine combines three technologies – immune focusing, self-assembling nanoparticles, and DNA delivery – into a single platform for the first time. In addition to its other advantages, the vaccine could be stored at room temperature, making it potentially easier to transport to remote or developing locations than existing mRNA vaccines, which require specialized cold storage.

“This is among the first next-generation vaccines that will have more advanced features and broader protection,” said Daniel Kulp, Ph.D., associate professor in the Vaccine & Immunotherapy Center at The Wistar Institute and corresponding author of the study.

The paper, “Nucleic acid delivery of immune-focused SARS-CoV-2 nanoparticles drive rapid and potent immunogenicity capable of single-dose protection,” was published in the journal Cell Reports.

Existing vaccines include an unmodifided receptor binding domain of SARS-CoV-2 spike protein. The new vaccine includes a rationally engineered receptor binding domain using computational and structure-based design methodologies. The engineered receptor binding domain blocks ‘immune distracting’ sites and can therefore elicit stronger levels of protective, neutralizing antibodies.

Researchers then used naturally self-assembling proteins to form nanoparticles which display these highly engineered immunogens. By arranging themselves into structures that resemble an actual virus, the nanoparticles are more easily recognized by the immune system and transported to the germinal centers, where they activate B cells which produce protective antibodies.

Using nucleic acid vaccine delivery technology similar to mRNA, the nanoparticle vaccine is encoded in DNA and delivered into cells thereby giving genetic instructions for the body to build the immunogen internally. This is an advance over traditional vaccines that must be manufactured in specialized factories through complex vaccine production processes. In contrast to other vaccines, Dr. Kulp noted that one advantage of the DNA platform is that it doesn’t require refrigeration and it can also be quickly reformulated to target new variants.

In animal models, researchers found that the DNA delivered immune-focused nanoparticle vaccine produced much higher levels of neutralizing antibodies than the vaccine that wasn’t immune-focused.

“A difficulty with current vaccines is that neutralizing antibodies decline over time,” Kulp said. The nanoparticle vaccine produced durable responses after a single immunization out to six months in mice, unlike what we are seeing with current SARS-CoV-2 vaccines in people.

The ultimate test for SARS-CoV-2 vaccine candidates is protection from death in SARS-CoV-2 challenge experiments. The researchers found that in a lethal challenge model 100% of mice who received the immune-focused nanoparticle vaccine were protected from death with a single low dose. Most mice who received the standard, non-immune focused vaccine died within 10 days of challenge.

The vaccine assessment was conducted in both wild-type mice and mice that were genetically engineered to mimic human immune systems, he noted.

Even without being updated, the immune-focused vaccine showed a comparable level of antibody production to Delta, and other variants, Kulp said. That’s partly because of the immune focusing approach itself, he noted; in blocking parts of the receptive binding domain for the purpose of inhibiting non-neutralizing antibodies, it also blocks many of the areas affected by spike protein mutations. Studies on the Omicron variant are underway.

Researchers are seeking funding to begin human trials of the vaccine.

Co-author David B. Weiner, Ph.D., executive vice president, director of the Vaccine & Immunotherapy Center and the W.W. Smith Charitable Trust Professor in Cancer Research, at The Wistar Institute, said the vaccine could provide a needed step forward to improve protection against COVID-19.

“Current vaccine effects on reducing transmission of SARS-CoV-2 variants of concern including Delta and Omicron could be improved for their breadth of protection as well as their immune potency,” Weiner said. “This study demonstrates that using a nucleic acid approach combined with in vivo structural assembly of a glycan immune-focused nanoparticle drives single protection and neutralization against diverse variants of concern in a dose-sparing formulation. Additional studies of this vaccine approach for SARS-CoV-2 appear timely and important.”

Co-authors: Kylie M. Konrath, Kevin Liaw, Yuanhan Wu, Xizhou Zhu, Susanne N. Walker, Ziyang Xu, Neethu Chokkalingam, Nicholas J. Tursi, Mansi Purwar, Emma Reuschel, Drew Frase, Benjamin Fry, and Ami Patel from Wistar; Katherine Schultheis, Igor Maricic, Viviane M. Andrade, Kate E. Broderick, Laurent M.P.F. Humeau, and Trevor R.F. Smith from Inovio Pharmaceuticals; Himanshi Chawla and Max Crispin from the University of Southhampton; Jianqiu Du and Alan Moore from Indiana University; Jared Adolf-Bryfogle and Jesper Pallesen from the Institute for Protein Innovation; Matthew Sullivan from the University of Pennsylvania; and Christel Iffland from Ligand Pharmaceuticals.

Work supported by: Wistar Coronavirus Discovery Fund, CURE/PA Department of Health grant SAP# 4100083104, COVID/PA Department of Human Services grant SAP# 4100089371, NIH/NIAID CIVICs grant 75N93019C00051, Wistar SRA 16-4 / Inovio Pharmaceuticals, Indiana University.

Publication information: Nucleic acid delivery of immune-focused SARS-CoV-2 nanoparticles drive rapid and potent immunogenicity capable of single-dose protection, Cell Reports, 2022.

Latest Wistar Discoveries: Fine-tuning Vaccine Delivery in Preclinical Models to Advance MERS DNA Vaccine Candidate and Discovering New Targets for Cancer Therapy

A team of Wistar scientists led by Dr. David Weiner, Wistar executive vice president, director of the Vaccine & Immunotherapy Center and W.W. Smith Charitable Trust Professor in Cancer Research, and Dr. Ami Patel, Caspar Wistar Fellow, and collaborators have developed a synthetic DNA vaccine candidate for Middle East respiratory syndrome coronavirus (MERS-CoV).

A vaccine candidate based on their research was shown to be safe and tolerable in a recently completed human phase 1 study with a three-dose intramuscular injection regimen and is currently in phase 1/2a trial.

Our scientists continue to expand the preclinical studies of the vaccine in support of its clinical development. They have now tested intradermal delivery using a shortened two-dose immunization schedule in non-human primates (NHP).

“Low-dose delivery and shortened regimes are crucial to rapidly induce protective immunity, particularly during emerging outbreaks, as the current SARS-CoV-2 pandemic has emphasized,” said Weiner.

In a paper published in the journal JCI Insight, he and colleagues reported that low-dose intradermal administration induces potent immunity and protects from virus challenge. The low-dose regimen with intradermal delivery was more impactful in controlling disease and symptoms than the higher dose given intramuscularly.

“Intradermal delivery of synthetic DNA vaccines has significant advantages for rapid clinical development. It can be dose sparing and has higher tolerability in people compared with intramuscular injection,” said Patel.

Their experience developing this MERS vaccine candidate helped the team advance a COVID-19 vaccine through clinical trials in a short time.

Vaccine candidates that are simple to deliver, well tolerated, and can be readily deployed in resource-limited settings will be important to achieve control of infection for coronaviruses and other emerging infectious diseases.


The lab of Dr. Rugang Zhang, deputy director of The Wistar Institute Cancer Center, Christopher M. Davis Professor and leader of the Immunology, Microenvironment & Metastasis Program, studies the process of cellular senescence and the changes in gene expression that accompany it.

Cellular senescence is a stable state of growth arrest in which cells stop dividing but remain viable and produce an array of inflammatory molecules collectively defined as senescence-associated secretory phenotype (SASP). These molecules account for the complex crosstalk between senescent cells and neighboring cells and the effect of cellular senescence in various physiological processes like aging and diseases like cancer.

Although senescence is regarded as a powerful barrier for tumor development, the SASP plays a role during tumor development promoting the growth of established tumors.

In a new study published in Nature Cell Biology, Zhang and colleagues pointed out a new mechanism that allows cells to turn on a set of genes encoding for the SASP molecules.

“This mechanism may potentially be targeted to stop the tumor-promoting aspect of senescence while preserving its antitumor function,” said Zhang.

The team focused on two proteins called METTL3 and METTL14 that are known for other molecular functions and found that these proteins moonlight as regulators of gene expression that help turn on SASP genes.

“Although we focused on senescence, we envision that this function of METTL3 and METTL14 may be involved in many other biological processes beyond our current study,” said Zhang.