by Julie Rafferty, Tufts University

Scientists across Tufts who are part of the university’s Lyme Disease Initiative have recently received grants from the U.S. government, private foundations, and others totaling more than $7 million to attack the disease from all angles. This research expansion will build on an already impressive array of research discoveries that teams at Tufts have made to combat tick-borne diseases.

Since it was found 50 years ago on the Connecticut coastline, Lyme disease has spread across New England, the upper Midwest, and the Mid-Atlantic states, with bites by disease-infected deer ticks often yielding a bull’s-eye-shaped rash and fever that in some is followed by complications ranging from arthritis and brain fog to heart and brain tissue damage.

While Lyme disease can often be successfully treated with antibiotics, 10-20% of patients experience persistent fatigue, joint pain, and mental impairments that last for months or years. In some cases, it is never really clear whether a patient’s long-lasting symptoms signal persistent infection, reinfection, or malfunction by the body’s disease-fighting immune system.

The new grants will focus on teasing apart the underlying causes of chronic Lyme disease—and may also have implications for other diseases, including long COVID. Other newly funded research will hunt for better ways to diagnose and track Lyme infection and reinfection, and ways to prevent both Lyme and other tick-borne diseases, such as babesiosis.

Keep reading for more on these newly funded efforts, which represent just some of the ways Tufts is fighting Lyme and other tick-borne diseases.

Phospholipids: Key to Chronic Lyme and Faster Diagnosis?

Researchers Linden Hu, Peter Gwynne, and colleagues have recently received grants from the Department of Defense (DoD) and National Institutes of Health (NIH) totaling $4,555,445 to understand the underlying causes of chronic Lyme disease and conduct a large test of a promising screening tool to diagnose Lyme disease sooner, show when people are cured of an initial infection, and diagnose reinfection.

“The Lyme bacteria has a relatively small genetic code,” says Gwynne, who is a research assistant professor at Tufts University School of Medicine. “As a result, it adopts substances from its host in order to grow and multiply.”

One of those substances is a type of phospholipid which is the building block of cell membranes and creates a protective barrier around cells.

The NIH funding will enable the researchers to better understand how the Lyme disease organism’s use of its host’s phospholipids may trigger autoimmunity in some people and lead to chronic Lyme symptoms even after the initial infection has cleared.

“Lyme patients whose symptoms persist have elevated levels of autoantibodies against phospholipids as compared to patients whose symptoms fully resolved,” says Gwynne. “It may be that they still are infected, in which case testing for phospholipid antibodies may be a way to identify persistent infection. Or it may be that these individuals have an intrinsic defect in their ability to stop generating autoantibodies—and their continued symptoms are a sign of an autoimmune condition triggered by the Lyme infection.”

“While not all autoantibodies cause symptoms, they are, in general, known to cause disease through a wide range of mechanisms, including direct damage to cells, altered nerve signaling, and other factors,” says Hu, who is the principal investigator for the study, the Paul and Elaine Chervinsky Professor of Immunology, a professor of molecular biology and microbiology, and vice dean for research at the School of Medicine.

Studying blood and tissue samples

In the NIH-funded effort, the scientists will study blood and tissue samples from infected Lyme patients to determine if there are specific phospholipid autoantibodies that are markers for persistent Lyme disease, and which tissues these autoantibodies have an affinity for.

They will also develop a mouse model of Lyme disease to test for neurologic changes that the disease and resulting production of phospholipid autoantibodies may be causing.

“While we can’t test mice for ‘brain fog,’ we can test for changes in response to heat, cold, and other stimuli that could demonstrate that the mice have altered neurological reactions when they receive purified phospholipid autoantibodies from patients with persistent Lyme disease,” Gwynne says.

Chris Dulla, a professor in the department of neuroscience at the School of Medicine and Graduate School of Biomedical Sciences, will be a key collaborator in this phase of the research.

The DoD grant takes to scale earlier work where the researchers demonstrated in smaller human studies that a diagnostic test they developed could detect Lyme disease sooner, show when people are cured of the infection, and diagnose reinfection.

The diagnostic test detects autoantibodies that infected individuals produce against the co-opted phospholipids. These autoantibodies—which mistakenly can also target and react with a person’s own tissues and organs—quickly appear when a person or organism is infected with Lyme, and then quickly disappear once the rest of the immune system has kicked in.

“The host recognizes them and has been trained to downregulate,” says Hu.

Current testing makes it difficult to diagnose reinfection or successful treatment. “If our tests are successful with the large panel of samples we are using for the DoD project, we will have a commercially viable product that will make it easier to tell if the Lyme disease has been successfully treated and if a person may have become reinfected if symptoms persist,” Hu adds.

Because antiphospholipid antibodies are frequently seen in autoimmune diseases like lupus, the test may also serve to identify who is more likely to develop persistent Lyme symptoms, Hu says.

Chronic Lyme and Immune System in Hyperdrive

Klemen Strle, an assistant research professor of molecular biology and microbiology at Tufts School of Medicine, received a new grant of $475,000 from the Global Lyme Alliance to take a different approach to understanding persistent Lyme disease. This research will examine whether a different maladaptive immune system response to the Lyme bacterium Borrelia burgdorferi is the underlying trigger for lingering long-term symptoms.

Research published in May by Strle’s team in the Center for Disease Control and Prevention’s Emerging Infectious Diseases journal found abnormally high levels of an immune system marker called interferon-alpha in the blood of people who had been treated for Lyme but had lingering symptoms months later.

“Interferon-alpha is one of a group of proteins in the body that tells immune cells to gear up to fight off bacteria or viruses,” says Strle. “Interferon-alpha is actually used to treat certain cancers and hepatitis C, but it can have significant side effects similar to those seen in persistent Lyme disease. Elevated levels of interferon-alpha are also seen in people with long COVID.”

The May study was completed by examining spinal fluid and blood from 79 long-term Lyme suffers with neurological symptoms. In the newly funded research, Strle and his collaborators will expand that study to several hundred patients to see if the pattern persists, whether age or an underlying genetic risk factor increases risk of persistent Lyme symptoms, and what triggers immune dysregulation.

Their research will also focus on those with persistent symptoms following infection with tick-borne encephalitis and COVID-19. These efforts may help scientists and clinicians better understand other conditions which seem to have similar symptoms, including long COVID.

If successful, the research could lead to new screening tools to identify those at risk for persistent symptoms after Lyme disease as well as new treatments, such as the anti-IFN alpha therapies used in autoimmune conditions such as lupus.

Collaborators in this research are based across the U.S. and Europe, including colleagues at the University Medical Center Ljublijana, Slovenia; the University of Illinois, Urbana-Champaign; the University of Utah; and Johns Hopkins University.

Immune System First Responders and Chronic Lyme

Tanja Petnicki-Ocwieja, research assistant professor at the School of Medicine, is studying another facet of an altered immune response to the Lyme disease bacterium that may trigger persistent symptoms. Like Strle, her efforts may help scientists better understand both chronic Lyme and long COVID.

Petnicki-Ocwieja’s $200,000 grant from the Global Lyme Alliance focuses on innate immune memory, also known as trained immunity, which alerts the immune system to a foreign invader and helps the immune system respond quickly to intruders it hasn’t encountered before.

Even though the innate immune system isn’t as specific as the adaptive immune system—which uses antibodies and T cells to target specific threats—it can also “remember” previous encounters with harmful substances like bacteria and viruses and respond if the intruder returns.

In most circumstances, the innate immune memory has evolved mechanisms that enable it to respond to harmful infectious agents while not attacking “good” bacteria that form our microbiome and perform important positive functions in our bodies. “This balance is crucial for maintaining both a healthy microbiome and for preventing a runaway immune system that is overreacting once an infectious agent has been vanquished,” she says.

“The Lyme bacteria has found a way to trick host immune systems into thinking it is a ‘good’ bacteria, so the immune system ignores it when it sees it again over the course of long-term infection. This allows the bacteria to survive in stealth mode long-term in hosts. Since the symptoms of Lyme disease are due to the immune response, this also benefits the host by reducing symptoms,” she says.

Petnicki-Ocwieja’s research will examine two key components of innate immune memory: macrophages and hematopoietic stem cells. Macrophages are a type of white blood cell that engulfs invaders as well as stimulating other cells involved in immune function. Hematopoietic stem cells are primitive cells in bone marrow from which all cellular elements of blood arise, including macrophage and lymphocytes in the adaptive immune system.

Epigentic Changes

This long-term memory is controlled by epigenetic changes, but their role in Lyme disease is unknown. She hypothesizes that epigenetic changes that occur during the initial Lyme infection influence how these cells function and, in turn, how the immune system responds over time.

“We suspect that in most people these epigenetic changes help reduce symptoms. But in patients with chronic Lyme, something goes awry that allows cells to continue to respond like the first time they see the bacteria and cause significant inflammation,” she says. “Some COVID-19 researchers think something similar may be happening in long COVID.”

The new research, to be conducted in mice and then human cells, will characterize whether and how an innate immune memory malfunction may be causing symptoms of chronic Lyme disease. If successful, researchers could develop a test to detect those susceptible to persistent Lyme caused by this mechanism.

“There are a number of epigenetic treatments used in cancer immunotherapy which could then be tested in patients with persistent Lyme disease with such a fingerprint, potentially limiting recurring symptoms,” she says.

Collaborating with Petnicki-Ocwieja in this research is Hu.

With a new $210,372 grant from the NIH, Bourgeois will examine why the natural mouse host, in contrast to laboratory mice or humans, does not show symptoms of infection despite remaining infected for life.

“By better understanding the bacteria’s life cycle we hope to not only identify drug targets in rodents that could prevent spread of the bacteria in nature, but also identify ways to make humans respond more like the mice and avoid Lyme disease symptoms,” he says. 

Babesiosis

Edouard Vannier, an assistant professor at the School of Medicine and a researcher in the Division of Geographic Medicine & Infectious Diseases at Tufts Medical Center, and his colleagues have received two grants from the NIH and the DoD totaling $1,048,885 for research to prevent babesiosis.

Like Lyme disease, babesiosis is acquired during the bite of an infected deer tick. It can also be transmitted through blood transfusion.

Babesiosis, caused by the protozoan parasite Babesia microti, is relatively rare but has been steadily emerging in communities where Lyme disease has long been established. The first case of babesiosis was identified in a summer resident of Nantucket in 1969.

Babesiosis is now endemic in 10 states, including all six New England states plus New York and New Jersey. Babesiosis is also endemic in the upper Midwest, particularly in Minnesota and Wisconsin.

Anyone can be infected with Babesia microti, but the disease is most severe and potentially life-threatening in people over 60, people who have had their spleen removed, and people with a weakened immune system. Common symptoms include fatigue, fever, chills, sweats, loss of appetite, and headache. The disease can be complicated by organ failure and blood clots, even ending in death.

Because Babesia microti, like malaria parasites, replicate in red blood cells, Vannier’s research is using insights gained from malaria prevention and treatment to tackle it. In the $178,000 grant from the NIH, Vannier will test an anti-malarial drug, tafenoquine, with the long-term goal of seeing if it can prevent symptomatic babesiosis in people exposed to deer ticks.

The drug tafenoquine

Vannier and his colleagues from Brown University and Yale University were the first to report on the therapeutic efficacy of tafenoquine in an elderly immunocompromised patient who was suffering from relapsing babesiosis.

The new study will explore the drug’s ability to prevent Babesia microti infection by testing it at different doses and frequencies in older but otherwise healthy mice and in young immunocompromised mice. These studies, if successful, will lay the groundwork for clinical trials in humans to determine its effectiveness for prevention and cure.

“Until now, prevention of babesiosis has consisted of recommendations to avoid tick-infested areas and minimize tick exposure in endemic areas,” says Vannier.

“Our case report and several mouse studies suggest that tafenoquine could be used for the prophylaxis of babesiosis. It’s unclear how much, when, and how often tafenoquine needs to be administered to prevent babesiosis from developing. If this research is successful, we could have an FDA-approved drug readily available for the prevention of severe babesiosis in those most at risk.”

Collaborators in the NIH study are Sam Telford III, professor in the department of infectious disease and global health at Cummings School of Veterinary Medicine at Tufts University, and Jesse DeLuca, chief of clinical pharmacology at Walter Reed Army Institute of Research.

In their $870,885 grant from the DoD, Vannier seeks to develop a vaccine for the pre-exposure prophylaxis of babesiosis. This effort will build upon his identification of 24 parasite antigens that are targeted by the immune system as mice manage to resolve an intense infection with Babesia microti.

The researchers have narrowed down to three antigens the list of those which are most promising. They will test in mice whether immunization with one or several of these antigens protects young mice from infection, and whether protection is as strong in older mice as it is in younger mice.

In another approach to prevention, Hu, Telford, and colleagues have received new contracts totaling $885,000 to work with Tarsus Pharmaceuticals to help develop a drug, lotilaner, that will kill ticks before they have had a chance to transmit infections. This medication is already available to prevent Lyme disease in dogs. Using a unique system developed by Tufts and the NIH, they are testing the ability of the drug to kill ticks quickly after they start feeding on people.

“If the drug works as well in humans as it does in dogs, this could be a game changer,” says Hu. “The drug could be taken once before someone goes camping, for example, or be taken by someone who lives in a tick-infested area and protect that person against multiple tick-borne diseases for 1-3 months.”

SOURCE: Tufts University