Wendy Picking, professor of veterinary pathobiology and principal investigator at Bond Life Sciences Center sits in her office and shows off some noteså she jotted down about the vaccines she’s working on. | Photo by Beni Adelstein, Bond LSC
By Beni Adelstein
Wendy Picking uses the power of proteins to fight pesky pathogens like Pseudomonas aeruginosa.
Picking and her team are one step closer to completing their mission to develop weapons like vaccines to fight against this bacterium. In March, they published these findings in Nature’s Journal, npj Vaccines.
“If your immune system is weakened and you get Pseudomonas in the hospital, you’re probably going to die,” said Picking, a principal investigator at Bond Life Sciences Center and professor of Veterinary Pathobiology. “We’re doing the basic research, so one day we can make a vaccine to prevent Pseudomonas, so you don’t die in the ER.”
Wendy has spent years developing vaccines against Pseudomonas aeruginosa and other bacteria like Shigellaflexneri with husband, Bill Picking, who focuses on the inner workings of the bacteria.
Pseudomonasaeruginosa causes pneumonia — a lung infection — while Shigella species causes diarrhea. Neither of these are any fun. These and other bacterial infections grow increasingly resistant to drug treatment in hospitals and beyond, so scientists need new ways to combat these pathogens.
A vaccine prepares the body to fight those bothersome bacteria.
By introducing a protein called an antigen into the body, it mimics an infection to trigger a defensive response. It’s like that antigen is a mug shot, so the body’s immune system recognizes what it’s up against and builds antibodies — a weapon tailor-made to fight it. The next time that pathogen tries to infect, the body will have had a way to fight it off.
For Wendy, making proteins that exist in the bacteria work toward this purpose is key.
In 2020, she earned her claim to fame — the discovery that fusing proteins together from the tip of the bacteria’s needle-like syringe amplifies an immune response to a vaccine to help fight off infection. Her lab was the first to discover this method works for these specific pathogens of Pseudomonas and Shigella.
“Producing proteins is expensive so we fuse the two tips to create a self-adjuvating protein, which combines two proteins to trigger and amplify a response,” Picking said.
When she says self-adjuvating, Wendy just means they created a new molecule that both stimulates the immune system and enhances that immune response. It’s like a go signal attaches itself to the vaccine’s proteins. The go signal tells the body to be more aggressive with fighting off those pathogens. Ideally, this will help fight off nasty symptoms of pneumonia or diarrhea.
These fused proteins originally helped the bacteria infect humans. They sit on the tip of a needle-like structure called a type 3 secretion system, which injects specialized proteins into cells to avoid being detected and attacked.
Wendy notes that developing the right animal models is one important part of creating a new vaccine. She has used mice for the Pseudomonas vaccine and rabbits for the Shigella vaccine.
“What you’re trying to do is mimic a human disease in a non-human model system, and you have to be sure that you’re stimulating the immune response in the right way,” she said.
Researchers observe how vaccines affect the immune systems of those animals and apply that knowledge to humans.
In their experiments, mice treated with these fused proteins survived being infected with Pseudomonas unlike the mice that received the placebo.
Now, Wendy’s team continues research on Pseudomonas and is shifting to research a Shigella vaccine. They will continue to test out the protein fusion method, refining vaccine candidates to fight off even more pesky pathogens.
Her most valuable findings are not limited to the experiments, and she said the most rewarding part of her work is seeing former students be successful.
“The most important lesson is picking your staff. Counting on your team, getting along with each other and working together is crucial,” she said. “I can now crash and burn; if these kids we work with are successful, then we’ve left the legacy that we wanted.”
“I want these vaccines to go to market, but we may be retired or dead when that happens.”
Wendy is looking forward to seeing what her group can come up with now.
New technologies like transcriptomics, RNA sequencing, and bioinformatics — available through MU’s research Core facilities in Bond LSC — will help them move their vaccine work forward to achieve this mission. Those pesky pathogens don’t stand a chance.
Wendy Picking’s most recent publication is “A protein subunit vaccine elicits a balanced immune response that protects against Pseudomonas pulmonary infection.” It appeared in the journal npj Vaccines in March 2023.
Lab of Olga Baker, a Bond LSC researcher and professor of otolaryngology at the University of Missouri. From left to right, Harim Tavares dos Santos, Olga Baker, Kihoon Nam, and Frank Maslow. | Photo by Sarah Kiefer, Bond LSC
By Sarah Kiefer
A digital declutter is a way to get rid of the seemingly endless files of old photos and documents, but when Harim Tavares dos Santos started sorting through computer files from the Baker Lab at Bond LSC, one image stood out and led him down a rabbit hole.
The picture showed tuft cells, a rare type of cell on his screen that seemed to wave hello with their finger-like structures.
“They looked different from other cells, so I looked into it more and I found that they actually had a name, but not much other than the basic research had been done on them,” said Tavares dos Santos – a senior research scientist in the Baker lab at Bond LSC.
Those tuft cells may be an important link in his study of Sjögren’s disease, a chronic autoimmune disease that destroys cells that make saliva and tears. He recently identified these cells in ducts – responsible for expelling saliva – of the submandibular glands across species in mice, pigs and humans using transmission electron microscopy, a process that can magnify a sample up to 2 million times its size.
Tuft cells — named after their tuft-like microvilli — serve as sentries on the surface of organs to detect chemicals then signal immune and nerve cells. In the gut, these specialized epithelial cells can sense chemicals from parasites and microorganisms to alert the body of the invaders. While first found in the intestines, they also line airways, nasal cavities and other hollow organs. For Tavares dos Santos, their presence in salivary glands provides a possible link to Sjögren’s.
Looking like a bottle-shaped base topped with a latex glove, these cells were first discovered in 1956, but have been vastly understudied. They use receptors similar to those that detect sweet and bitter taste to regulate inflammation in several organs, including the intestine.
Tuft cells are currently an enigma in many tissues, leaving more questions than answers for researchers. After establishing their presence in salivary glands across species, Tavares dos Santos wants to pinpoint what they do there. He hypothesizes that tuft cells are involved in Sjögren’s pathogenesis. Still, ongoing studies are being conducted to confirm or refute this notion. Tavares dos Santos recently obtained a NIH K99/R00 grant and a Sjögren’s Foundation grant to work on this project, in which Baker will mentor Tavares dos Santos during the training phase of both of these grants.
“These types of cells were just forgotten in time and there is now a huge gap between the discovery of tuft cells and the first reports of their function,” Tavares dos Santos said. “I hope to work towards closing that gap and determining their specific role in the salivary glands and how that impacts clinical treatments for Sjögren’s patients.”
Harim Tavares dos Santos looks at the fluorescent tuft cells that appear green on the monitor. Identifying how tuft cells work in salivary glands is essential in understanding the causes of Sjögren’s disease. | Photo by Sarah Kiefer, Bond LSC
He wants to understand the molecular, morphological, and functional roles of tuft cells in salivary glands health and disease. Once Tavares dos Santos deciphers the code for the role tuft cells play, he plans to expand this knowledge to other conditions affecting salivary gland function such as irradiated salivary glands from patients treated for head and neck cancers.
But for now, Tavares dos Santos will focus on Sjögren’s.
“This work makes me feel challenged because tuft cells are poorly understood, so everything we discover about the role of tuft cells in salivary glands is new information,” Tavares dos Santos said. “I am excited about the idea that this research could help people in the future.”
Harim recently received an NIH K99/R00: Pathway to Independence Award as well as a Sjögren’sFoundation grant that gives him the resources and the support to become a future faculty principal investigator.
Lab of Roman Ganta, Bond LSC principal investigator and McKee endowed professor of veterinary pathobiology. | Photo by Sarah Kiefer, Bond LSC
By Sarah Kiefer
It only takes a quiet walk through the Missouri woods to encounter ticks. As they crawl from the rich vegetation among the bushes and grass onto humans and animals alike, they wreak havoc on their hosts by passing on disease causing bacterial pathogens.
One of those pathogens known to cause a 100-year-old disease is Rocky Mountain Spotted Fever (RMSF). University of Missouri scientist, Roman Ganta, hopes to understand its inner workings to one day develop a vaccine against it.
Like several tick-borne pathogens belong to rickettsial bacteria, such as Ehrlichia Anaplasma, and Rickettsia species that cause severe diseases in various vertebrate animals, including people. Ganta has been investigating and developing vaccines against important tick-borne diseases that cause Anaplasmosis, Ehrlichiosis and RMSF in people, companion animals and agricultural animals.
“We are doing basic research first because it has to be translational, so we cannot continue without first understanding the fundamentals of the root cause of a disease,” said Ganta, a Bond Life Sciences Center principal investigator and McKee endowed professor of veterinary pathobiology. “Then we can apply that understanding to develop prevention methods to make the environment healthier and improve lives.”
RMSF is one of the most dangerous tick-borne diseases and without treatment, it can lead to death in a portion of the infected. RMSF gets its name from the red spots that appear on a patient’s skin due to damaged blood vessels. These spots can swell the arms, legs, face, and body, causing difficulty breathing and other complications. The bacterium Rickettsia rickettsii is primarily transmitted from an infected tick, although person-to-person and animal-to-animal transmission is possible.
Several tick species are known to harbor the pathogen, including the Lone Star tick (Amblyomma americanum) which has widespread distribution in Missouri and several neighboring and southeastern states.
Ganta’s research builds toward vaccines to protect against a number of tick-borne diseases.
The Ganta lab picks apart each individual gene of pathogenic rickettsial bacteria transmitted by ticks in causing diseases to identify whether it is essential for pathogens’ survival in ticks, vertebrate animals, or both.
Ph.D. graduate student Jonathan Ferm (right) prepares a pipette with cultures to inject into a sample while Dominica Genda (left) takes notes on the process. | Photo by Sarah Kiefer, Bond LSC
“We expected that all the genes for the vertebrate host would be equally essential for the tick, but that was not the case,” Ganta said. “Only a small group of genes were identified as equally essential for a pathogen’s growth in a tick which was surprising.”
Armed with this knowledge, the team can build a better defense against tick-borne rickettsial diseases.
“Because we now know what proteins are essential, we can create enhanced strategies for drug and vaccine development in promoting the health of people, companion and agricultural animals,” he said.
National Institutes of Health (NIH) funding helps him work on multiple vector-borne disease vaccine projects such as RMSF, Ehrlichiosis and Anaplasmosis. A vector refers to an organism—often a blood-sucking insect or tick—that carries a pathogen from one animal to another. Those pathogens are responsible in causing diseases like RMSF, Ehrlichiosis, Anaplasmosis, and Lyme disease.
To successfully infect a vertebrate host, the pathogens have developed ways to avoid rejection and hang on to their hosts. The pathogens derive nutrients from the hosts to support their survival. While scientists don’t entirely understand what benefit ticks get out of a pathogen, Ganta looks for clues in how the genes in a pathogen change their protein expression in vertebrate hosts and ticks. He wants to understand the gene expression of pathogens during their growth in ticks and vertebrate hosts so that he can identify what the pathogen needs to survive and use that knowledge to craft a vaccine specific to each pathogen.
Roman Ganta inspects a sample of cultures that is grown in order to generate a pellet that is then put under a microscope for closer observation. | Photo by Sarah Kiefer, Bond LSC
“How the proteins are expressed differently provide us with the whole story of what is essential for a pathogen in a tick and what is essential for it in a vertebrate host. Once we know that, the next step is to see what happens if you take those essential proteins out of those pathogens,” Ganta said. “Do the bacteria die or do they survive and grow differently in one host versus another? That’s what we investigate.”
Ganta has been pursuing this line of research for over 15 years with the continuous NIH grant support that began in 2007. His work on the RMSF vaccine project started as part of a $3.7 million NIH grant in August 2021 when he was a professor at Kansas State University (KSU). He has since continued it after his move to MU in early 2023.
Ganta’s vaccine projects on Ehrlichia and Anaplasma species pathogens started with an additional $3.2 million NIH grant that began in June of 2020 at KSU and has since been transferred to MU. Ganta’s research success has been creation of vaccines that are 100% effective in protecting dogs from the devastating diseases;RMSF and Ehrlichiosis, and Anaplasmosis in cattle. RMSF vaccine results were published in a paper in 2019, while Ehrlichiosis and Anaplasmosis vaccine work were published in 2015 and 2022, but this kind of vaccine research is yet to be extended to humans.
Ganta feels that improving the health of companion and agricultural animals will have a positive impact on the health and well-being of people. Ganta’s current focus is to test how long a vaccine protection will last and if the vaccines protect against infection in all areas of the world where the diseases are widespread.
“If these vaccines don’t protect for a long period of time, what do we do next? We have to find a better solution to extend the immunity, such as offering a booster vaccination or modify the vaccines to offer protection against distinct pathogen strains,” Ganta said.
Ganta’s RMSF vaccine is a whole-cell antigen inactivated vaccine, while Ehrlichiosis and Anaplasmosis vaccines are based on modified live attenuated bacteria. These approaches take the entire “cocktail” of proteins from the bacteria to trigger immune responses in patients without causing diseases.
“What do you do when you go to Alaska in the wintertime? You put on a coat. What do you do when you go to the Caribbean in the summertime? You wear something more comfortable for the hot weather. That process is called adaptation, and pathogens in ticks and vertebrate hosts do the exact same thing, adapting to different host environments” Ganta said.
Because pathogens constantly evolve, the vaccines must be able to handle those changes. Currently, Ganta and his team are fine-tuning vaccine variations for RMSF, so that the vaccine works against different strains of the bacteria and to define the length of protection in animals. Similarly, his team has been investigating and improving the vaccines against Ehrlichiosis and Anaplasmosis.
The team’s active modified live vaccines against tick-borne infections from Ehrlichia and Anaplasma pathogens are also effective in preventing the diseases such as Ganta’s modified live vaccine that has been effective in preventing canine ehrlichiosis and bovine anaplasmosis.
His research with the USDA grant support has been attempting to define pathogenesis with a far-reaching goal to develop a vaccine against a foreign animal tick-borne disease caused by Ehrlichia ruminantium. This pathogen results in heartwater disease in sub-Saharan Africa and parts of the Caribbean in both domestic and wild ruminants and can cause up to 80% fatalities in livestock population if introduced into the U.S. accidentally.
Ganta hopes that his continued vaccine research will one day help minimize several tick-borne diseases impacting people, companion animals and food animals.
