Protein energy
malnutrition decreases immunity and increases susceptibility to influenza
infection.
Andrew Taylor,1Keyur Vora,1Weiping
Cao,1Wun-Ju
Shieh,2Sherif
Zaki,2Jacqueline
Katz,1Suryaprakash
Sambhara,1 and
Shivaprakash Gangappa1
1Influenza
Division, National Center for Immunization and Respiratory Diseases, Centers
for Disease Control and Prevention, Atlanta, GA 2Divison
of High Consequence Pathogens and Pathology, National Center for Emerging and
Zoonotic Infectious Diseases, Centers for Disease Control and Prevention,
Atlanta, GA
Protein energy malnutrition (PEM), a common cause of secondary immune
deficiency in children, is associated with an increased risk of infection. We
investigated the influence of PEM on susceptibility and immune responses to
influenza virus infection using a mouse model. Groups of weanling mice
maintained on isocaloric diets providing varying levels of protein energy
[18%/adequate protein (AP), 5%/low protein (LP), and 2%/very low protein (VLP)]
were infected with either 2009 A(H1N1) or laboratory-adapted H1N1 virus and
assessed for disease severity and immune responsiveness. We found that compared
to mice fed with AP and LP diets, mice maintained on the VLP diet exhibited an
increase in virus-induced mortality and morbidity. Mice maintained on the VLP
diet demonstrated diminished IFN
levels and
increased virus titer and inflammatory cell types in lung tissue, compared with
mice on higher protein content diets. Moreover, groups of mice maintained on
the VLP diet showed a lower hemagglutination-inhibition antibody response and
reduced total numbers of splenic NP-specific CD8+ T cells compared with mice on
higher protein content diets. Following re-feeding of the VLP group with the AP
diet, post-infection morbidity, mortality and virus titer were all improved.
Our results highlight the impact of protein energy on immunity to influenza
infection and suggest balanced protein energy replenishment may be one strategy
to boost immunity against influenza viral infections.
levels and
increased virus titer and inflammatory cell types in lung tissue, compared with
mice on higher protein content diets. Moreover, groups of mice maintained on
the VLP diet showed a lower hemagglutination-inhibition antibody response and
reduced total numbers of splenic NP-specific CD8+ T cells compared with mice on
higher protein content diets. Following re-feeding of the VLP group with the AP
diet, post-infection morbidity, mortality and virus titer were all improved.
Our results highlight the impact of protein energy on immunity to influenza
infection and suggest balanced protein energy replenishment may be one strategy
to boost immunity against influenza viral infections.
The Journal of Immunology, 2011, 186, 67.5
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