Tag: interferons

Categories : Immune System New Compounds and TreatmentsTags :

“Two for the Price of One” – New Process that Drives Anti-viral Immunity is Discovered

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Scientists at Trinity College Dublin have discovered a new process in the immune system that leads to the production of an important family of anti-viral proteins called interferons. They hope the discovery will now lead to new, effective therapies for people with some autoimmune and infectious diseases.

Reporting in Nature Metabolism, Luke O’Neill, Professor of Biochemistry in the School of Biochemistry and Immunology at Trinity, and his team have found that a natural metabolite called Itaconate can stimulate immune cells to make interferons by blocking an enzyme called SDH. 

Co-lead author, Shane O’Carroll, from Trinity’s School of Biochemistry and Immunology, said: “We have linked the enzyme SDH to the production of interferons in an immune cell type called the macrophage. We hope our work will help the effort to develop better strategies to fight viruses because interferons are major players in how our innate immune system eliminates viruses – including COVID-19.” 

Co-lead author, Christian Peace, from Trinity’s School of Biochemistry and Immunology, added: “Itaconate is a fascinating molecule made by macrophages during infections. It’s already known to suppress damaging inflammation but now we have found how it promotes anti-viral interferons.”

Working with drug companies Eli Lilly and Sitryx Ltd, the next step is to test new therapies  based on Itaconate in various diseases, with some autoimmune diseases and some infectious diseases on the likely list. And the work potentially extends to other disease contexts in which SDH is inhibited, such as cancer, and could reveal a new therapeutic target for SDH-deficient tumours.

Prof O’Neill said: “With Itaconate you get two for the price of one – not only can it block harmful inflammation, but it can also help fight infections. We have discovered important mechanisms for both and the hope now is that patients will benefit from new therapies that exploit Itaconate and its impacts.” 

Clinical trials in patients are set to start next year.  

Source: Trinity College Dublin

Categories : Immune SystemTags :

Interferons Drive Lupus Symptoms and Affect Treatment

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A woman with Systemic Lupus Erythematosus. Source: Wikimedia CC0

In a new study, researchers from Johns Hopkins Medicine say they have uncovered insights as to why lupus symptoms and severity present differently in individuals with the autoimmune condition. The team says this is a crucial step forward in understanding biological mechanisms behind lupus, and may also lead to shifts in how clinicians treat patients with the condition.

The full report, published in Cell Reports Medicine, concludes that specific combinations and elevated levels of immune system proteins, known as interferons, are associated with certain lupus symptoms such as skin rashes, kidney inflammation and joint pain. Interferons normally help to fight infection or disease, but are overactive in lupus, causing widespread inflammation and damage. The study also shows that other common lupus-related symptoms cannot be explained by increased interferon levels.

“For years, we have accumulated knowledge that interferons play a role in lupus,” says corresponding author and rheumatologist Felipe Andrade, MD, PhD, associate professor of medicine at the Johns Hopkins University School of Medicine. He says this research began with questions about why certain lupus treatments were ineffective for some patients. “We have seen instances where the patient surprisingly didn’t improve – we wondered if certain interferon groups were involved.”

Some lupus treatments are designed to suppress a specific group of interferons, known as interferon I. In clinical trials for these treatments, the team observed some patients failing to improve, despite genetic tests showing high interferon I levels before treatment, or what experts call a high interferon signature. The team believed that two other interferon groups, interferon II and interferon III, may be to blame for these poor treatment responses.

To investigate, the team looked at how different combinations of interferon I, II or III, and their overactivity, may present in people with lupus. Researchers took 341 samples from 191 participants to determine the activity of the three interferon groups, and used human cell lines engineered to react to the presence of each specific interferon group to analyse the samples. Through this process, researchers determined that the majority of participants fell into four categories: those only with increased interferon I; those with a combination of increased interferons I, II and III; those with a combination of increased interferons II and III; or those with normal interferon levels.

Researchers were able to use these findings to also make several associations between these interferon combinations and lupus symptoms. In those with elevated interferon I, lupus was mainly associated with symptoms affecting the skin, such as rashes or sores. Participants with elevated levels of interferon I, II and III exhibited the most severe presentations of lupus, often with significant damage to organ systems, such as the kidneys.

Not every symptom found in lupus was associated with elevated interferons, though. The formation of blood clots and low platelet counts, which also affect clotting, did not have an association with increased levels of interferon groups I, II or III. Researchers say this indicates that both interferon-dependent and other biological mechanisms are involved in this complex disease. The study also found that genetic testing of genes associated with these interferon groups, or the interferon signature, did not always indicate elevated interferon levels. They plan to investigate this in future studies.

“What we’ve seen in our study is that these interferon groups are not isolated; they work as a team in lupus and can give patients different presentations of the disease,” says rheumatologist Eduardo Gómez-Bañuelos, MD, PhD, assistant professor of medicine at Johns Hopkins and the study’s first and additional corresponding author. Evaluating a patient’s elevated interferon combinations allows for a better understanding of how they may react to treatments, and would allow clinicians to group them into clinical subtypes of lupus, Gómez-Bañuelos explains.

Source: Johns Hopkins Medicine

Categories : Immune SystemTags :

Study Reveals a Possible Secret to Viral Infection Resistance in Humans

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Colourised scanning electron microscope image of a natural killer cell. Credit: National Institutes of Health

Studying resistance to viral infections in humans is difficult because it’s virtually impossible to disentangle resisting being infected from simply not being exposed. By studying women who were accidentally exposed to hepatitis C (HCV) over 40 years ago, scientists in Ireland have uncovered a secret that may explain why some people are able to resist viral infections.

The extraordinary work, published in Cell Reports Medicine, has wide-ranging implications from improving our fundamental understanding of viral resistance to the potential design of therapies to treat infected people.

From 1977–79, several thousand women in Ireland were exposed to the hepatitis C virus through contaminated anti-D, a medication made using plasma from donated blood and given to Rhesus negative women who are pregnant with a Rhesus positive foetus. The medication prevents the development of antibodies that could be dangerous in subsequent pregnancies. Some of the anti-D used during the 1977–79 period was contaminated with hepatitis C.

Infected women fell into three groups: those who were chronically infected; those who cleared the infection with an antibody response; and those who appeared protected against infection but yet produced no antibodies against hepatitis C.

“We hypothesised that women who seemed to resist HCV infection must have an enhanced innate immune response, which is the ancient part of the immune system that acts as a first line of defence,” said senior author Cliona O’Farrelly, Professor of Comparative Immunology in Trinity’s School of Biochemistry and Immunology.

“To test this we needed to make contact with women exposed to the virus over forty years ago and ask them to help us by allowing us to study their immune systems to hunt for scientific clues that would explain their differing responses.

“After a nationwide campaign over 100 women came forward and we have gained some unique and important insights. That so many women – many of whom have lived with medical complications for a long time – were willing to help is testament to how much people want to engage with science and help pursue research with the potential to make genuine, positive impacts on society. We are deeply grateful to them.”

The scientists ultimately recruited almost 40 women from the resistant group, alongside 90 women who were previously infected.

In collaboration with the Institut Pasteur in Paris they then invited almost 20 women in each group to donate a blood sample that they stimulated with molecules that mimic viral infection and lead to activation of the innate immune system.

“By comparing the response of the resistant women to those who became infected, we found that resistant donors had an enhanced type I interferon response after stimulation,” said first author Jamie Sugrue, PhD Candidate. Type I interferons are a key family of antiviral immune mediators that play an important role in defence against viruses including hepatitis C and SARS-CoV-2, or COVID.

“We think that the increased type I interferon production by our resistant donors, seen now almost 40 years after the original exposure to hepatitis C, is what protected them against infection.

“These findings are important as resistance to infection is very much an overlooked outcome following viral outbreak, primarily because identifying resistant individuals is very difficult – since they do not become sick after viral exposure, they wouldn’t necessarily know that they were exposed. That’s why cohorts like this, though tragic in nature, are so valuable – they provide a unique opportunity to study the response to viral infections in an otherwise healthy population.”

The lab’s efforts are now focused on leveraging these biological findings to unpick the genetics of viral resistance in the HCV donors. Their work on HCV resistance has already helped ignite international interest in resistance to other viral infections such as SARS-CoV-2.

The O’Farrelly lab has expanded its search for virus-resistant individuals by joining in the COVID human genetic effort and by recruiting members of the public who have been heavily exposed to SARS-CoV-2 but never developed an infection.

Source: Trinity College Dublin

Categories : COVID Immune SystemTags :

SARS-CoV-2 Variants are Evolving to Evade Human Interferons

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SARS-CoV-2 infecting a human cell
Infected cell covered with SARS-CoV-2 viruses. Source: NIAID

Researchers have investigated how antiviral proteins called interferons interact with SARS-CoV-2. The study, published in PNAS, focuses on how the innate immune system defends against this coronavirus, which appears to be adapting to evade this interferon response.

The study was the result of a collaborative effort, including the laboratories of Mario Santiago, PhD, associate professor of medicine and Eric Poeschla, MD, professor of medicine, both at the University of Colorado School of Medicine.

While the adaptive arm of the immune system robustly deals with infection by generating antibodies and T cells, the innate arm forms an earlier, first line of defence by recognising conserved molecular patterns in pathogens.

“SARS-CoV-2 just recently crossed the species barrier into humans and continues to adapt to its new host,” said Prof Poeschla. “Much attention has deservedly focused on the virus’s serial evasions of neutralising antibodies. The virus seems to be adapting to evade innate responses as well.”

The type I Interferon system is a major player in antiviral defence against all kinds of viruses. Virus-infected cells release type I interferons (IFN-α/β), which warn the body of the intrusion. Secreted interferons cause susceptible cells to express powerful antiviral mechanisms to limit viral growth and spread. The interferon pathway could significantly reduce the levels of virus initially produced by an infected individual.

“They are clinically viable therapeutic agents that have been studied for viruses like HIV-1 for years,” explained Prof Santiago. “Here we looked at up to 17 different human interferons and found that some interferons, such as IFNalpha8, more strongly inhibited SARS-CoV-2. Importantly, later variants of the virus have developed significant resistance to their antiviral effects. For example, substantially more interferon would be needed to inhibit the omicron variant than the strains isolated during the earliest days of the pandemic.”

The data suggests that COVID clinical trials on interferons, dozens of which are listed in clinicaltrials.gov, may need to be interpreted based on which variants were circulating when the study was conducted. Researchers say that future work to decipher which of SARS-CoV-2’s multitude of proteins might be evolving to confer interferon resistance may contribute in that direction.

Source: University of Colorado Anschutz Medical Campus