A common amino acid found in food could play a key role in the immune system's ability to detect threats, according to new research from Rockefeller University. The study, published in Cell, found that when the body runs low on arginine, cells struggle to produce enough MHC-1, a protein that helps immune cells recognize cancer and viruses. In mice, increasing dietary arginine reduced colon cancer tumors and lessened the severity of influenza and SARS-CoV-2 infections. The findings suggest that an inexpensive supplement could eventually aid cancer treatments and viral defense, but human research is still needed.
The study was led by Sohail Tavazoie, director of the Elizabeth and Vincent Meyer Laboratory of Systems Cancer Biology at Rockefeller University. Qiushuang Wu, a postdoc in the lab, was first author. The team has spent years investigating how arginine influences cancer; in 2023, they found that depriving colon cancer cells of arginine caused them to accumulate more genetic mutations.
In the latest research, Wu examined how arginine shortages affect protein production. She identified 414 proteins whose levels dropped abnormally when arginine was scarce. The researchers also found an effect involving three genes from the HLA family, which provide instructions for producing MHC-I proteins. These proteins act as warning signals on cell surfaces, presenting fragments of proteins from inside the cell to T cells. When arginine was unavailable, ribosomes stalled while trying to manufacture MHC-I, reducing the signals that alert immune cells to threats.
The team then tested whether changing arginine levels in an animal's diet could influence disease outcomes. Mice on low-arginine diets developed more colon cancer tumors, while those consuming higher amounts developed fewer. Similarly, mice eating more arginine had milder symptoms from influenza and SARS-CoV-2. Surprisingly, giving mice arginine after they were already infected with influenza also improved their outcomes.
"Not only did mice with an arginine-rich diet have milder symptoms from viral infections, giving the mice arginine after influenza infection improved their outcomes too. That was very surprising," Wu said.
Tavazoie noted that arginine levels naturally decline with age and inadequate nutrition can further reduce the amount available to cells, which the researchers suspect may contribute to weakened immune defenses. “Qiushuang's findings illuminate how poor diet and aging -- during which arginine levels naturally decline -- could create the perfect storm for the initiation of colon cancer,” he said.
The researchers see potential for arginine supplementation alongside existing cancer immunotherapies, which help the immune system recognize and attack cancer cells. If low arginine interferes with the molecular signals required for that recognition, restoring the nutrient might help treatments work more effectively. Tavazoie said arginine supplementation could be readily tested in patients receiving immunotherapies or given to high-risk populations exposed to viral pathogens.
Wu said the work suggests arginine could perhaps be used in combination with other therapies. “Our work reveals how a lack of arginine interferes with the immune system, and suggests that upping arginine intake could prove beneficial,” she said.
The study does not establish that taking arginine supplements prevents or treats cancer, influenza, or COVID-19 in humans, but it reveals a connection between nutrition and immunity that could provide a practical starting point for future studies.
Analysis
Why This Matters
- Arginine is inexpensive and widely available, making any beneficial effects broadly accessible.
- Could enhance the effectiveness of existing immunotherapies by ensuring immune cells can properly detect cancer.
- Age-related decline in arginine may contribute to higher vulnerability to cancer and viruses in older adults, suggesting supplementation could help protect at-risk populations.
Background
Arginine is an amino acid the body produces naturally and obtains from protein-rich foods. It is essential for making proteins. Unusually low arginine levels have been linked to diseases including colon cancer, but the mechanism had been unclear. This study reveals how arginine deficiency disrupts the production of MHC-I proteins, which are critical for the immune system's ability to present warning signals on cell surfaces. The work builds on earlier findings from the same lab that arginine deprivation in colon cancer cells led to more genetic mutations.
What to Watch
- Human clinical trials to determine whether arginine supplementation produces similar benefits in people.
- Combination studies with existing cancer immunotherapies.
- Potential use as a preventive supplement for high-risk populations during respiratory virus seasons.
Checked
12 claims in this story checked against 1 source: 12 supported.
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- SupportedThe headline says an arginine supplement may help the immune system fight cancer and viral infections, as the study suggests.Latest Science News -- ScienceDaily: “The findings, published in the journal Cell, raise the possibility that an inexpensive, readily available supplement could eventually become a useful addition to cancer treatments and strategies for combating viral infections.”
- SupportedThe summary says arginine could help restore MHC-I production in cells.Latest Science News -- ScienceDaily: “supplying a moderate amount of arginine [...] could help restore production of this important protein.”
- SupportedThe summary says higher dietary arginine reduced colon cancer tumors in mice.Latest Science News -- ScienceDaily: “Mice receiving diets low in arginine developed more colon cancer tumors. In contrast, mice consuming higher amounts of the amino acid developed fewer tumors.”
- SupportedThe summary says higher dietary arginine reduced viral illness severity in mice.Latest Science News -- ScienceDaily: “Mice consuming more arginine experienced less severe symptoms from viral infections”
- SupportedWu said: “Not only did mice with an arginine-rich diet have milder symptoms from viral infections, giving the mice arginine after influenza infection improved their outcomes too. That was very surprising.”Latest Science News -- ScienceDaily: “"Not only did mice with an arginine-rich diet have milder symptoms from viral infections, giving the mice arginine after influenza infection improved their outcomes too," Wu notes. "That was very surprising."”
- SupportedTavazoie said: “Qiushuang's findings illuminate how poor diet and aging -- during which arginine levels naturally decline -- could create the perfect storm for the initiation of colon cancer.”Latest Science News -- ScienceDaily: “"Qiushuang's findings illuminate how poor diet and aging -- during which arginine levels naturally decline -- could create the perfect storm for the initiation of colon cancer.”
- SupportedWu said: “Our work reveals how a lack of arginine interferes with the immune system, and suggests that upping arginine intake could prove beneficial.”Latest Science News -- ScienceDaily: “"Our work reveals how a lack of arginine interferes with the immune system, and suggests that upping arginine intake could prove beneficial," says first author Qiushuang Wu”
- SupportedWu identified 414 proteins whose levels dropped abnormally when arginine was scarce.Latest Science News -- ScienceDaily: “She identified 414 proteins whose levels dropped abnormally when arginine was scarce.”
- SupportedThe researchers found an effect involving three HLA-family genes that provide instructions for producing MHC-I proteins.Latest Science News -- ScienceDaily: “the researchers uncovered a more unexpected effect involving three genes from the HLA family. These genes provide instructions for producing proteins associated with MHC-I”
- SupportedThe study was published in Cell.Latest Science News -- ScienceDaily: “The findings, published in the journal Cell”
- SupportedGiving mice arginine after they were infected with influenza improved their outcomes.Latest Science News -- ScienceDaily: “Giving mice additional arginine after they had already been infected with influenza also improved their outcomes.”
- SupportedThe study does not establish that arginine supplements prevent or treat cancer, influenza, or COVID-19 in humans.Latest Science News -- ScienceDaily: “The findings do not establish that taking arginine supplements prevents or treats cancer, influenza, or COVID-19 in humans.”