THURSDAY, Oct. 27 (HealthDay News) -- Obese individuals have reduced levels of influenza antibody titers and decreased CD8+ T-cell responses 12 months after influenza vaccination, according to a study published online Oct. 25 in the International Journal of Obesity.
Patricia A. Sheridan, Ph.D., from the University of North Carolina in Chapel Hill, and colleagues assessed the antibody response to the 2009 to 2010 season inactivated trivalent influenza vaccine (TIV) in healthy weight, overweight, and obese participants at one and 12 months after vaccination. Influenza-stimulated peripheral blood mononuclear cell (PBMC) cultures were used to assess activation of CD8+ T cells and expression of interferon-γ and granzyme B.
The investigators found a positive association between body mass index (BMI) and higher initial fold increase in immunoglobulin G antibodies detected by enzyme-linked immunosorbent assay to TIV, which was confirmed in a subset study by hemagluttination inhibition antibody. Higher BMI correlated with a greater decline in influenza antibody titers 12 months post-vaccination. Compared with healthy weight individuals, obese individuals had decreased CD8+ T-cell activation and decreased expression of functional proteins when PBMCs were challenged ex vivo with vaccine strain virus.
"If antibody titers and influenza vaccination-induced memory CD8+ T-cell populations are not maintained over time by the obese individuals, they may be at risk for suboptimal vaccine response," the authors write.