Overview of influenza vaccination cohorts and changes in vaccine responses in HR and LR for each strain. Credit: Science Advances (2024). DOI: 10.1126/sciadv.adq7006
So-called high-dose influenza vaccines are available for older adults. That’s because their immune systems don’t always respond well to standard flu vaccines. Why this happens and the molecular processes behind it are still not understood.
However, in the current research effort, scientists at the Center for Individualized Infectious Medicine (CiiM), a joint initiative of the Helmholtz Center for Infectious Disease Research (HZI) and the Medical School of Hannover (MHH), are targeting around 230 participants. We are conducting a cohort study. The 65-year-old was able to identify the key molecule.
The researchers hope their findings will help further boost immune responses to influenza vaccines in older adults in the future. The study was published in Science Advances.
Influenza is prevalent in early October every year. “Effective vaccines are especially important for the elderly, as they are at particularly high risk of developing severe disease,” said Yang Li, Scientific Director of CiiM and Head of Personalized Medicine Bioinformatics at HZI. says the professor. .
Because the standard flu vaccine is not effective enough, there are so-called high-dose flu vaccines intended for people over 60 or 65. But what is the reason?
“As we age, our immune system is less able to mount an adequate immune response,” Lee explains. “In our study, we wanted to elucidate exactly what this is involved in, which molecular processes play a role here, and identify approaches that can be used to improve the immune response. .”
The study was based on a cohort of 234 participants aged 65 and older who received influenza vaccination. Blood was collected at a total of five different time points before and after vaccination. This has been investigated in detail using the latest molecular biology techniques and is summarized under the term “multi-omics.”
The researchers used statistical and computational models to analyze the vast amount of data generated. By doing so, we investigated how the immune response differs between people who respond well to vaccination (responders) and those who do not respond well (non-responders).
“We were able to identify a number of key molecules that correlate with a good immune response in responders after vaccination. However, in non-responders, these characteristic molecules are reduced or not detected at all. ,” explains scientist Dr. Saumya Kumar. is a member of Yang Li’s research group at CiiM and the lead author of this study.
“And, unlike responders, non-responders showed increased numbers of certain activated immune cells in the blood, so-called natural killer cells. At different levels of the omics layer, responders and non-responders showed “I was able to identify the differences between the two.” It was certainly very clear. ”
In the study, scientists also investigated whether they could predict how well a person’s immune response would develop before vaccination. “To do this, we looked at blood samples taken before vaccination. Those who did not respond afterwards showed elevated levels of interleukin-15 before vaccination. High levels of this messenger molecule. “This may indicate an ongoing chronic inflammatory process in older people,” says Lee.
In subsequent studies in mouse models, the researchers were able to show that mice lacking receptors for the messenger molecule had an improved immune response.
“Interleukin-15 appears to be responsible for the lack of an adequate immune response, so it could be a good predictive biomarker,” Li says. “To improve the immune response, it is also possible to reduce the elevated levels of interleukin-15 before vaccination by administering appropriate active substances. However, such an approach is still far away.”
Scientists also uncovered another interesting approach in their research. That is, those who did not respond had significantly lower levels of long-chain fatty acids in their blood before vaccination than those who did.
“Older adults often suffer from concomitant diseases associated with chronic inflammatory processes. Certain long-chain fatty acids have anti-inflammatory properties and support the development of an overall good immune response,” Kumar said. says.
“Providing an adequate supply of long-chain fatty acids, such as those found in fish oil and healthy nuts, may be an effective way to improve the immune response to influenza vaccination and general health. Whether and how effective it is remains to be studied.”
“Our study included such a large number of participants from the 65+ age group for the first time, allowing us to gain important insights into the shaping of vaccine responses following influenza vaccination in older adults. ” says Lee. .
“We were able to identify molecules that are key to good and bad immune responses, which can be used for further research. Our findings may help improve influenza vaccination in older adults in the future. We hope that this will help further boost the immune response of patients.”
Further information: Saumya Kumar et al, Systemic dysregulation and molecular insights into poor influenza vaccine responses in an aging population, Science Advances (2024). DOI: 10.1126/sciadv.adq7006
Provided by Helmholtz German Research Center Association
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