title: Protein energy malnutrition decreases immunity and increases susceptibility to influenza infection in mice.
abstract: BACKGROUND
  Protein energy malnutrition (PEM), a common cause of secondary immune deficiency in children, is associated with an increased risk of infections. Very few studies have addressed the relevance of PEM as a risk factor for influenza.
  
  
  METHODS
  We investigated the influence of PEM on susceptibility to, and immune responses following, influenza virus infection using isocaloric diets providing either adequate protein (AP; 18%) or very low protein (VLP; 2%) in a mouse model.
  
  
  RESULTS
  We found that mice maintained on the VLP diet, when compared to mice fed with the AP diet, exhibited more severe disease following influenza infection based on virus persistence, trafficking of inflammatory cell types to the lung tissue, and virus-induced mortality. Furthermore, groups of mice maintained on the VLP diet showed significantly lower virus-specific antibody response and a reduction in influenza nuclear protein-specific CD8(+) T cells compared with mice fed on the AP diet. Importantly, switching diets for the group maintained on the VLP diet to the AP diet improved virus clearance, as well as protective immunity to viral challenge.
  
  
  CONCLUSIONS
  Our results highlight the impact of protein energy on immunity to influenza infection and suggest that balanced protein energy replenishment may be one strategy to boost immunity against influenza viral infections.
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Taylor
authors.forename: Weiping
authors.initials: W
authors.lastname: Cao
authors.forename: Keyur P
authors.initials: KP
authors.lastname: Vora
authors.forename: Juan
authors.initials: J
authors.lastname: De La Cruz
authors.forename: Wun-Ju
authors.initials: WJ
authors.lastname: Shieh
authors.forename: Sherif R
authors.initials: SR
authors.lastname: Zaki
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Katz
authors.forename: Suryaprakash
authors.initials: S
authors.lastname: Sambhara
authors.forename: Shivaprakash
authors.initials: S
authors.lastname: Gangappa
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D018753:Diet, Protein-Restricted; D004195:Disease Models, Animal; D004198:Disease Susceptibility / Q000276:immunology*; D005260:Female; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D008168:Lung / Q000276:immunology / Q000473:pathology / Q000821:virology; D051379:Mice; D009976:Orthomyxoviridae Infections / Q000150:complications* / Q000276:immunology* / Q000401:mortality; D011502:Protein-Energy Malnutrition / Q000150:complications*
chemical_list: D000914:Antibodies, Viral