Immune history shapes antibody responses to H5N1
A new paper published in Nature Medicine investigates how previous exposure to influenza viruses influences immune responses to H5N1, with a particular emphasis on immune imprinting. Historically, H5N1 viruses have been associated with a higher mortality rate in younger individuals compared to older individuals, possibly due to differences in immunological exposure.
The authors analyzed H5N1 antibody responses in serum samples from 157 individuals born between 1927 and 2016. They examined the relationship between antibody levels, birth year, and age, with a specific focus on immunological imprinting.
Antibody titers against H5N1 strains were higher in older individuals, suggesting that childhood exposure to earlier group 1 influenza viruses (H1N1 and H2N2) may enhance later immune responses to H5N1. Younger individuals, particularly young children, exhibited lower baseline H5-specific antibody levels but demonstrated significant seroconversion following H5N1 vaccination, indicating they may benefit more from vaccination in a pandemic scenario.
The analysis revealed that immune imprinting was a stronger predictor of antibody response than chronological age, highlighting the critical role of an individual's immunological history in shaping their immune response to H5N1. The study reinforces that immune imprinting from past influenza infections, particularly with group 1 viruses, plays a vital role in determining antibody responses to H5N1. Older individuals may exhibit greater resistance to H5N1 infection due to their immunological history, whereas younger individuals, with fewer prior exposures, may derive greater benefits from vaccination.
