title: Immune status and the development of Listeria monocytogenes infection in aged and young guinea pigs.
abstract: OBJECTIVE
  Consuming even low numbers of the foodborne pathogen, Listeria monocytogenes, places the elderly at risk for severe illness. The impact of immunomodulation on the development of listerial infection within a young and aged population after low dose challenge with L. monocytogenes was investigated.
  
  
  METHODS
  Animals received daily supplementation of vitamin E for a period of 21 days to promote immunomodulation, and were then orally challenged with 100 CFU of L. monocytogenes. Levels of CD8+, CD4+ and CD3+ T cells were used as markers to determine the influence of daily supplementation with vitamin E on immune response; the spleen and liver were harvested for microbiological analysis.
  
  
  RESULTS
  Higher numbers of animals became infected in control groups than in vitamin E-treated group. During the post-challenge period, vitamin E-treated aged animals showed faster CD8+ T cell proliferation than control aged animals.
  
  
  CONCLUSIONS
  Daily supplementation with vitamin E was more beneficial in young compared with aged animals in mitigating listerial infection. Results suggest exposure to even low numbers of L. monocytogenes can result in infection in both healthy young and aged populations.
authors.affiliation: Department of Food Science, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, 65 DudleyRoad, New Brunswick, NJ 08901-8520, USA.
authors.forename: Wen-Hsuan
authors.initials: WH
authors.lastname: Wu
authors.forename: Hoan-Jen E
authors.initials: HJ
authors.lastname: Pang
authors.forename: Karl R
authors.initials: KR
authors.lastname: Matthews
mesh_terms: D000367:Age Factors; D000818:Animals; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019587:Dietary Supplements; D004198:Disease Susceptibility / Q000276:immunology; D005260:Female; D006168:Guinea Pigs; D008088:Listeriosis / Q000276:immunology*; D018655:Lymphocyte Count; D014810:Vitamin E / Q000097:blood / Q000494:pharmacology; D014815:Vitamins / Q000097:blood / Q000494:pharmacology; D024502:alpha-Tocopherol / Q000097:blood
chemical_list: D014815:Vitamins; D014810:Vitamin E; D024502:alpha-Tocopherol