Submitted to: Journal of Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/18/2013
Publication Date: 1/21/2014
Citation: Du, X., Wang, J., Niu, X., Smith, D., Wu, D., Meydani, S.N. 2014. Dietary wolfberry supplementation enhances protective effect of flu vaccine against influenza challenge in aged mice. Journal of Nutrition. 144:224-229. Interpretive Summary: Aging is associated with increased occurrence of several infectious diseases like influenza (flu), which is a serious health problem worldwide. The flu vaccine is currently the most efficient way to prevent the flu, but the effectiveness of the vaccine is lower in the elderly due to the age-related decline in immune function; therefore, finding ways to safely enhance vaccine effectiveness could reduce the high rate of illness and death in the elderly. Wolfberry or goji berry has been shown to improve the body’s immune response and to enhance the body’s response to vaccination in the elderly. Our study focused on determining if wolfberry would increase the efficacy of the vaccine against a subsequent influenza infection. We tested the effectiveness of vaccinations on mice fed a diet containing wolfberry for 30 days. The mice were vaccinated and then challenged with the flu virus. Results showed that mice fed wolfberry had a better response to vaccination and reduced symptoms than the mice that were not supplemented with wolfberry. These findings suggest that dietary supplementation with wolfberry may be used in conjunction with vaccines to improve the immune system’s response to flu and therefore to enhance the effectiveness of the flu vaccine in the elderly.
Technical Abstract: Current vaccines for influenza do not fully protect the aged against influenza infection. Wolfberry, or goji berry, has been shown to improve immune response including enhanced antibody production in response to vaccination in the aged; however, it is not known if this effect of wolfberry would translate to better protection after influenza infection nor is its underlying mechanism well understood. To address these issues, we fed mice a diet containing 5 percent milk-based preparation of wolfberry for 30 d, then immunized them with an influenza vaccine at days 31 and 52, which was then followed by a challenge with influenza A/Puerto Rico/8/34 virus. Results showed that mice fed wolfberry had higher influenza antibody titers after vaccination and further improved symptoms (less post-infection weight loss) above and beyond the protective effect observed in the mice treated by vaccine alone. Further, an in vitro mechanistic study showed that wolfberry supplementation enhanced maturation and activity of antigen presenting dendritic cells (DC) in aged mice, as indicated by phenotypic change in expression of DC activation markers MHC-II, CD40, CD80, and CD86, and functional change in DC’s production of cytokines IL-12 and TNF-alpha and DC’s endocytosis. Also, adoptive transfer of wolfberry -treated bone marrow DC (loaded with OVA 323-339-peptide) from the aged mice promoted antigen-specific T cell proliferation as well as IL-4 and IFN-gamma production in CD4 T cells. In summary, our data indicate that dietary wolfberry enhances the efficacy of influenza vaccination resulting in better host protection to prevent subsequent influenza infection; this effect may be partly attributed to improved DC function.