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This Article Full Text (Papers in Press[PDF]) All Versions of this Article: jmm.0.013250-0v1 58/12/1559    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Ren, Z. Articles by Meydani, S. N. PubMed PubMed Citation Articles by Ren, Z. Articles by Meydani, S. N. Agricola Articles by Ren, Z. Articles by Meydani, S. N.

Effect of Age on Susceptibility to Salmonella typhimurium Infection in C57BL/6 Mice

¹ Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts;

² Department of Microbiology and Molecular Biology, Tufts University

³ E-mail: simin.meydani{at}tufts.edu

Received June 4, 2009
Accepted August 28, 2009

Aging is associated with a decline in immune function, which predisposes the elderly to higher incidence of infections. Information on the mechanism of age-related increase in susceptibility to ST is limited. In particular, little is known regarding the involvement of the immune response in this age-related difference. We employed the streptomycin (STREP)-pretreated C57BL/6 mice to develop a mouse model that would demonstrate age-related difference in susceptibility and immune response to ST. In this model, old mice inoculated orally with 3x10⁸ CFU or 1x10⁶ CFU doses of ST, had significantly greater ST colonization in ileum, colon, Peyer's patches, spleen, and liver than those of young mice. Old mice had significantly higher weight loss than young mice on days 1 and 2 postinfection. In response to ST infection, the old mice failed to increase ex vivo production of IFN- and TNF- in spleen and mesenteric lymph node cells to the same degree as those observed in the young mice, which was associated with their inability to maintain the presence of neutrophils and macrophages at a 'youthful' level. These results indicate that STREP-pretreated C57BL/6 old mice are more susceptible to ST infection than young mice, which might be due to impaired IFN- and TNF- production as well as the corresponding change in the number of neutrophils and macrophages in response to ST infection compared to young mice.