New research from the University of Queensland has found that a metabolic hormone known as leptin has been linked to a poor vaccine antibody response in the general population for influenza and hepatitis B vaccines.
The Australian research was published in Nature Communications on Monday, and outlines how leptin receptor deficiency can impair antibody responses in both immunisation and infection — making low levels of the hormone a risk for vaccine failure.
The study, which was conducted before the onset of COVID-19, was led by Professor Di Yu and examined responses to the influenza and hepatitis B virus (HBV) vaccines. It found that the frequency and function of a person’s TFH cells correlated with protective antibody production.
“Using multiple advanced techniques in immunology, genetics and biochemistry, our study found leptin directly promoted the development and function of cells which are vital in triggering an antibody response,” Professor Yu said.
Even among healthy populations, scientists have found that a ‘significant portion of people’ experience a poor response to vaccination with the efficacy of a standard influenza vaccine dose being 70-90% for young adults and only 17-53% for people aged over 65. One of the key factors that limits a person’s response to a vaccine is their TFH cell activity.
Professor Yu said that leptin was a metabolic hormone largely produced by fat tissue and that fasting could produce low levels of the serum, going on to affect the regulation of a TFH cell differentiation and function.
“Vaccines have been known for a very long time to have a different efficacy for individuals,” Yu said.
“Although our genetics partially contribute to the difference, other factors are also essential.
“When we are fit and healthy, we have a much better vaccine efficacy,” he added
The researcher explained that because good health and good metabolism were associated, people who have suffered malnutrition in their lives can tend to have weaker leptin levels. Being obese, however, can cause an individual to have leptin resistance, also leading to a poorer vaccine response.
Professor Yu said he hoped this latest study could help develop new strategies to improve vaccine efficacy, including vaccines to immunise the population against COVID-19. More research in the area (such as testing COVID-19 vaccines to determine biomarkers) was critical because different individual responses to vaccines could cause a ‘major bottleneck’ for large-scale vaccination programs, he added.
“During the era of the COVID-19 pandemic, the successful vaccination for SARS-CoV-2 is the major hope to bring society back to normalcy,” Professor Yu said.