title: Dietary fish oil enhances circulating interferon-gamma in mice during listeriosis without altering in vitro production of this cytokine.
abstract: The objective of this study was to investigate the impact of feeding mice a diet rich in n-3 polyunsaturated fatty acids (PUFA) from fish oil on the interferon-gamma (IFN-gamma) response during an active infection with Listeria monocytogenes. Weanling female C3H/Hen mice were fed experimental diets containing 20% by weight one of the following fats: soybean oil, lard, or a mixture of menhaden fish oil and corn oil (17:3, w/w). After 4 weeks, mice were injected with 10(5) live L. monocytogenes, and the concentration of IFN-gamma in serum and spleen was determined 0, 2, 4, and 7 days postinfection by enzyme-linked immunosorbent assay (ELISA). Fish oil-fed mice showed significantly higher IFN-gamma in their blood at 2 and 4 days postchallenge compared with mice fed the soybean oil-containing or lard-containing diets (p < 0.001). A higher concentration of IFN-gamma was also found in the spleen homogenate of fish oil-fed mice on day 4 postchallenge (p < 0.005). To examine in vitro IFN-gamma production, splenocytes were isolated from fish oil-fed and soybean oil-fed mice on day 4 postchallenge and cultured with concanavalin A (1 microgram/ml and 10 micrograms/ml) for 24 and 48 h. There were no significant differences in the IFN-gamma concentration in cell culture supernatants between these diet treatments. This study demonstrated that the elevation in the concentration of IFN-gamma in blood and spleen during murine listeriosis is accentuated and prolonged by dietary n-3 PUFA, and these effects may not be due to changes in IFN-gamma production.
authors.affiliation: Department of Animal Sciences, University of Missouri, Columbia, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Fritsche
authors.forename: C
authors.initials: C
authors.lastname: Feng
authors.forename: J N
authors.initials: JN
authors.lastname: Berg
mesh_terms: D000818:Animals; D004041:Dietary Fats / Q000494:pharmacology; D005260:Female; D005395:Fish Oils / Q000494:pharmacology*; D007371:Interferon-gamma / Q000096:biosynthesis / Q000097:blood*; D008088:Listeriosis / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H
chemical_list: D004041:Dietary Fats; D005395:Fish Oils; D007371:Interferon-gamma