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© 2008 American Society for Nutrition J. Nutr. 138:813-819, April 2008

Nutritional Immunology

Docosahexaenoic Acid–Enriched Fish Oil Consumption Modulates Immunoglobulin Responses to and Clearance of Enteric Reovirus Infection in Mice1,2

Eleni Beli3, Maoxiang Li3–5,, Christopher Cuff6 and James J. Pestka3–5,*

3 Department of Food Science and Human Nutrition, 4 Department of Microbiology and Molecular Genetics, 5 Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824 and 6 Department of Microbiology, Immunology, and Cell Biology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506

* To whom correspondence should be addressed. E-mail: pestka{at}msu.edu.


   ABSTRACT
TOP
 ABSTRACT
Introduction
 Materials and Methods
 Results
 Discussion
 LITERATURE CITED
 
We hypothesized that consumption of the (n-3) PUFA, docosahexaenoic acid (DHA), modulates the mucosal immune response to enteric infection with respiratory enteric orphan virus (reovirus), a model intestinal pathogen. Mice were fed either AIN-93G control diet, containing 10 g/kg corn oil and 60 g/kg high oleic acid safflower oil, or AIN-93G, containing 10 g/kg corn oil and 60 g/kg DHA-enriched fish oil, for 4 wk and then orally gavaged with reovirus strain Type 1 Lang, (T1/L). Reovirus-specific IgA antibody was first detectable in the feces of mice fed a control diet at 6 d postinfection (PI) and was further elevated at 8 and 10 d PI. IgA responses in DHA-fed mice were similar at 6 and 8 d PI but greater at 10 d PI (P < 0.05). Both reovirus-specific serum IgA and IgG2a were comparably induced in mice fed control or DHA diets. Reovirus-specific IgA and IgG2a secretion by ex vivo Peyer's patch, lamina propria, and spleen cultures derived from control and DHA groups were comparable. Although both groups carried similar numbers of reovirus plaque forming units per intestine, DHA-fed mice shed nearly 10 times more viral RNA in feces than control mice at 2, 4, and 6 d PI (P < 0.05). However, viral RNA was not detectable in either group at 8 and 10 d. Taken together, these data suggest that DHA consumption did not markedly alter mucosal or systemic Ig responses to reovirus but delayed clearance of the virus from the intestinal tract.


   Introduction
TOP
 ABSTRACT
 Introduction
Materials and Methods
 Results
 Discussion
 LITERATURE CITED
 
Consumption of long chain (n-3) PUFA found in fish oil, such as docosahexaenoic acid (DHA)7 and eicosapentaenoic acid (EPA), can potentially provide benefits to individuals suffering from an array of inflammatory conditions (1). These effects relate in part to the capacity of (n-3) PUFA to decrease production of inflammatory eicosanoids, cytokines, and reactive oxygen species. IgA-nephropathy (IgAN), the most common primary glomerulonephritis (2,3), is caused by aberrant upregulation of circulating IgA and the subsequent deposition of IgA immune complexes in the kidney mesangium that leads to end-stage renal failure. (n-3) PUFA have been demonstrated to retard progressive renal inflammation and fibrosis in patients with late-stage IgAN (4).

In our laboratory, we have developed a mouse model for IgAN that is induced by feeding the trichothecene mycotoxin deoxynivalenol (DON) (5). DON-ingestion dramatically elevates serum concentrations of IgA, IgA immune complexes, and polymeric IgA and causes mesangial IgA deposition in the kidney, all of which mimic early clinical signs of human IgAN (6–8). Dietary supplementation with (n-3) PUFA-enriched fish oils blocks DON-induced elevation of serum IgA and IgA immune complexes, as well as IgA deposition in the kidney mesangial (9–13), suggesting that these fatty acids might delay or suppress aberrant IgA production in the early stages of the disease. Subsequent studies have revealed that this suppression results in part from the attenuation of interleukin-6 transcription in the macrophages of (n-3) PUFA–fed mice (11,13).

The pronounced ameliorative effect of (n-3) PUFA consumption on DON-induced IgA production in the mouse suggests that these lipids might have clinical value for humans with a predilection for IgAN. At the same time, these findings raise serious questions as to whether (n-3) PUFA might deleteriously interfere with the IgA responses to pathogens encountered in the intestinal mucosa. The potential for (n-3) PUFA to alter mucosal immune responses, such as IgA production, has been addressed only to a very limited extent. For example, influenza virus–specific lung secretory IgA and serum IgG responses are significantly lower in mice fed fish oil (14). In human patients suffering from proctocolitis, administration of (n-3) PUFA does not change the percentage of IgA-containing cells in the rectal mucosa (15). In contrast, positive correlations exist between (n-3) PUFA and IgA concentrations in breast milk (16). Thus, the impact of (n-3) PUFA on mucosal IgA responses is difficult to predict.

Type 1 L (T1/L) respiratory enteric orphan virus (reovirus) a human isolate, has been used extensively as a murine model to study immune responses to viral infection of the enteric tract (17). This virus is a potent inducer of antibody responses in the mouse, as reflected by robust mucosal IgA production as well as serum IgA and IgG production (18–20). Oral infection with reovirus also induces specific CD4+ and CD8+ cytotoxic lymphocytes (18,21) as well as Th1 and Th2 cytokine responses (22,23). These responses enable the murine intestine to clear reovirus within 1 to 2 wk.

Reovirus has been successfully employed to elucidate how the murine gut mucosal immune response is affected by toxicants (17,21,24–26) and, more recently, by the nutraceutical 3,3'-diindolylmethane (27). This model might similarly be useful for evaluating the effects of (n-3) PUFA on enteric immunity. Accordingly, the objective of this study was to test the hypothesis that (n-3) PUFA consumption suppresses humoral responses to and clearance of enteric reovirus. Specifically, the effects of consuming a diet containing a high DHA concentration were evaluated in mice challenged orally with T1/L reovirus.


   Materials and Methods
TOP
 ABSTRACT
 Introduction
 Materials and Methods
Results
 Discussion
 LITERATURE CITED
 
    Chemicals and virus. All chemicals were purchased from Sigma unless otherwise noted. Reovirus serotype 1, strain Lang (T1/L) was used for all experiments. The virus was grown in L929 fibroblast cells at 34°C in DMEM medium with 5% (v:v) fetal bovine serum (Atlanta Biologics), 105 U/L of penicillin, and 100 mg/L of streptomycin. A third-passage plaque-purified virion was used for mouse infection and prepared by extraction with 1,1,2-trichloro-1,2,2-trifluoroethane, followed by discontinuous CsCl gradient centrifugation (200,000 x g; 3 h) (26,28). Titers of the purified virus were determined by plaque assay (29).

    Mice. Female B6C3F1 mice (4-wk-old) were purchased from Charles River Laboratories. All animal procedures were approved by the Michigan State Institutional Animal Care and Use Committee and were in accordance with the National Research Council guidelines. Mice were housed 3/cage in a humidity (45–55%)- and temperature (23–25°C)-controlled university animal-care facility room with a 12-h light and dark cycle. Mice were acclimated for 1 wk prior to experiment initiation and fed experimental diets until they were killed. Mice were infected and held in microisolator cages under negative pressure laminar flow in a Biosafety Level 2 room at the Michigan State University Research Containment Facility.

    Diets. Experimental diets were based on the AIN-93G formulation (Dyets) of Reeves (30), modified as described previously (13). Control diets contained 10 g/kg corn oil (Dyets) and 60 g/kg high oleic acid safflower oil (Hain-Celestial); DHA diets contained 10 g/kg corn oil and 60 g/kg DHA-enriched fish oil (Ocean Nutrition Canada). The DHA-rich oil contained 580 g/kg DHA and 100 g/kg EPA. This (n-3) PUFA concentration was selected because it was previously shown to effectively suppress DON-induced IgA production and mesangial IgA deposition (9). Compositions of the 2 diets are summarized in Table 1. Diets were prepared every 2 wk and stored in aliquots at –20°C.


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  		TABLE 1 Lipid composition in experimental diets

 
The capacity of this dietary regimen to increase (n-3) PUFA concentrations in Peyer's patches (PP) and spleen were confirmed over a 6-wk period, as described previously (10) by gas chromatography. Identification of each FAME peak was based on the comparison of the retention time with the standard FAME [PUFA-1 marine source, PUFA-2 animal source (Supelco), GLC 538, and GLC 463 (Nu-CHECK)].

    Experimental design and sample preparation. Mice were fed fresh control or DHA diets daily for 4 wk prior to reovirus infection. They were then infected by oral gavage with 3 x 107 reovirus plaque forming units (PFU) in a total volume of 0.1 mL PBS (pH 7.4) containing 20 g/L of gelatin (19). Mice were fed control or DHA diets until experiment termination. At specified time intervals, mice were bled from the lateral saphenous vein (31) and fecal pellets were collected. Plasma was separated from blood samples and stored at 4°C. Fecal pellets were kept frozen at –20°C until analysis. Pellets were weighed and suspended in PBS to a 10 g/L final concentration, held on ice for 2 h, and sonicated for 15 s. Suspensions were centrifuged 1,600 x g; 10 min at 4°C, and 1.4 mL of the supernatant was cleared by centrifugation at 18,000 x g; 10 min at 4°C. Supernatant fractions were used directly for specific antibody detection by ELISA or for total RNA isolation.

Upon experiment termination, mice were anesthetized with isoflurane and exsanguinated via the portal vein. PP, spleens, and intestines were collected from the killed mice and processed as described below.

    Lymphoid fragment cultures. PP, lamina propria, and spleen cultures were used to assess ex vivo Ig secretion (26). Briefly, 7 PP per mouse were removed from the intestine, pooled, and washed 3 times in sterile HBSS (Gibco) with 5 mg/L of gentamicin and 2 times with a tissue culture medium consisting of Roswell Park Memorial Institute 1640 medium supplemented with 100 mL/L fetal bovine serum, 2 mmol/L L-glutamine, 0.5 µmol/L 2-mercaptoethanol, 5 mg/L of gentamicin, 105 U/L penicillin, and 100 mg/L streptomycin. Individual patches were cut in half and incubated in 6-well culture plates with 2 mL of culture media for 5 d at 37°C under 5% CO2 without additional stimulation. Spleens were similarly washed with a tissue culture media, cut in small pieces (2 mm x 2 mm), and incubated in 2 mL of culture media.

Lamina propria cultures were established by cutting the PP-depleted intestine longitudinally into 2-cm-long pieces. Fragments were washed at least 3 times with HBSS with 2 g/L NaHCO3, 0.1 mol/L HEPES, and 5 mg/L gentamicin. Half of the fragments were stored in 1 mL of sterile PBS containing 50 g/L gelatin (gel saline) at –80°C until analysis to be used for viral titer detection. Fragments from the other half were incubated for 30 min in 5 mmol/L EDTA in HBSS twice to remove epithelial cells. Fragments were washed twice more with media and finally incubated in 2 mL of media, as described above.

After 5 d of culture, PP, spleen, and lamina propria culture supernatants were harvested and reovirus-specific Ig determined by ELISA.

    Virus plaque assay. For viral plaque counts, intestinal segments were placed in 1 mL of sterile PBS, freeze-thawed 3 times, homogenized, and then sonicated (32). PFU were quantified as described previously (26,29).

    Real-time PCR. Total RNA was extracted from 200 µL of supernatant of 100 g/L fecal suspension using Trizol reagent (Invitrogen). Viral RNA was quantified by real-time PCR, as described by Li et al. (26). Purified reoviruses were added to fecal-pellet suspensions from vehicle mice at concentrations of 0, 104, 105, 106, 107,108, 109, and 1010 PFU/L for standard curve and sensitivity determination.

    ELISA. Serum, culture fluids, and fecal supernatant fractions were assayed for virus-specific antibodies by a modification (26) of a published ELISA method (32). OD at 450 nm was used as the endpoint for fecal, PP, spleen, and intestinal fragment cultures. Plasma antibody titers were defined as the last dilution yielded absorbance of 0.2 at 450 nm. A log of the dilutions was used to calculate the geometric means.

    Statistics. We used 2-way ANOVA to determine the effects of time and diet. Multiple pairwise comparisons were performed using the Bonferroni corrected t test. Data were reported as means ± SEM. The critical level for normality and equal variance test was {alpha} = 0.01 and the critical level for the rest of the comparisons was {alpha} = 0.05. When used for statistical analysis, nondetectable (ND) data were assigned the limit of detection value. The fatty acid incorporation experiment was conducted 1 time. All other data are representative of 2 separate experiments.


   Results
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 ABSTRACT
 Introduction
 Materials and Methods
 Results
Discussion
 LITERATURE CITED
 
Consumption of the DHA-enriched diet resulted in significantly higher DHA, EPA, and total (n-3) PUFA concentrations in the spleen and PP after 2 wk, whereas arachidonic acid concentrations were markedly lower after 2 wk (Table 2, 3). (n-3) PUFA concentrations did not significantly increase at wk 4 and 6 as compared with wk 2. Based on these findings, we chose a 4-wk period for feeding the mice control or experimental diets prior to reovirus infection.


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  		TABLE 2 Fatty acid composition of spleen phospholipids in mice fed a control or DHA-enriched diet1–3

 

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  		TABLE 3 Fatty acid composition of PP phospholipids in mice fed a control or DHA-enriched diet1–3

 
Reovirus-specific IgA antibody was first detectable in the feces of mice fed a control diet at 6 d postinfection (PI) and was further elevated at 8 and 10 d PI (Fig. 1A). By 10 d PI, these mice exhibited significantly higher levels of specific IgA than control mice. When ex vivo Ig secretion was measured in lamina propria cultures, those from control mice exhibited robust induction of reovirus-specific IgA at 5 d PI and this was further increased at 10 d PI (Fig. 1B). Induction of specific IgA secretion was higher in cultures from DHA-fed infected mice than cultures from infected mice fed a control diet at 5 d PI, but not 10 d PI. Ex vivo PP cultures prepared at 14 d PI from infected mice fed control and DHA diets were also found to secrete elevated but similar levels of reovirus-specific IgA (Fig. 2A) and IgG2a (Fig. 2B).


Figure 1
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  		FIGURE 1  Mucosal IgA responses to reovirus in mice fed a control or DHA-enriched diet. ELISA absorbances for reovirus-specific IgA in feces collected at different time points PI (A). Values are means ± SEM, n = 4. Reovirus-specific IgA in supernatants from ex vivo lamina propria fragments cultures (B). Values are means ± SEM, n = 6. Within a group, means without a common letter differ, P < 0.05. *Different from infected mice fed a control diet at that time, P < 0.05.

 

Figure 2
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  		FIGURE 2  Reovirus-specific Ig production in ex vivo PP cultures from mice fed a control or DHA-enriched diet. PP were collected at 14 d PI and production of reovirus-specific IgA (A) and IgG2a (B) were determined in ex vivo cultures. Values are means ± SEM, n = 6. Within a group, means without a common letter differ, P < 0.05.

 
Both reovirus-specific serum IgA and IgG2a were comparably induced at 7 and 14 d PI in mice fed control or DHA diets (Fig. 3). Analogous results were found for production of virus-specific IgA and IgG2a in ex vivo spleen cultures prepared at 14 d PI from control and DHA-fed mice (Fig. 4).


Figure 3
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  		FIGURE 3  Plasma reovirus-specific Ig responses in mice fed a control or DHA-enriched diet. Specific IgA (A) and IgG2a (B) titers determined in plasma by ELISA, (n = 6). Values are means ± SEM, n = 6. Within a group, means without a common letter differ, P < 0.05.

 

Figure 4
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  		FIGURE 4  Reovirus-specific Ig production in ex vivo spleen cultures from mice fed a control or DHA-enriched diet. Spleens were collected at 14 d PI and production reovirus-specific IgA (A) and IgG2a (B) were determined in ex vivo cultures (n = 6). Values are means ± SEM, n = 6. Within a group, means without a common letter differ, P < 0.05.

 
When infectious reovirus particles were quantified in the intestines (devoid of PP), both infected control and DHA-fed groups were found to carry nearly 105 PFU/intestine at 5 d PI (Fig. 5). By 10 d PI, the viral loads in both groups were reduced to 104 PFU/intestine.


Figure 5
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  		FIGURE 5  Reovirus PFU in intestines of mice fed a control or DHA-enriched diet. Values are means ± SEM, n = 6. ND, not detectable. Within a group, means without a common letter differ, P < 0.05.

 
Reovirus L2 RNA was detectable in the feces of control mice at 2, 4, and 6 d PI, but not at 8 and 10 d PI (Fig. 6A). Nearly 10 times more viral RNA was detectable in the feces of DHA-fed mice at 2, 4, and 6 d PI, however, viral RNA was not detectable at 8 and 10 d PI, similar to control mice. When PP were analyzed for reovirus L2 RNA in a parallel study, both groups exhibited similar levels of viral RNA at d 1 PI, indicative of equivalent reovirus entry into these tissues (Fig. 6B). At 3 d PI, significantly more viral RNA was detected in the DHA group. By 7 d PI, the DHA group exhibited nearly 104 L2 gene copies/µg total RNA, whereas the L2 gene was undetectable (<103 copies/µg total RNA) in the PP from mice consuming a control diet.


Figure 6
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  		FIGURE 6  Reovirus L2 RNA copy numbers in feces and PP from mice fed a control or DHA-enriched diet. Fecal pellets were collected at intervals and total RNA analyzed by PCR, (n = 4) (A). PP were collected at 0, 1, 3, and 7 d PI and total RNA analyzed by PCR (B). Values are means ± SEM, n = 6. ND, not detectable. Within a group, means without a common letter differ, P < 0.05. *Different from infected mice fed a control diet at that time, P < 0.05.

 

   Discussion
TOP
 ABSTRACT
 Introduction
 Materials and Methods
 Results
 Discussion
LITERATURE CITED
 
Gut mucosal immune responses to antigens are initiated and coordinated in the PP, which contain dendritic cells, macrophages, and lymphocytes (33). Subsequently, B and T lymphocytes migrate from the PP via the systemic compartment to the gut intestinal lamina propria and other distal mucosal sites, where they evoke humoral and cell-mediated effector responses. Enteric reovirus infection induces robust humoral and cell-mediated mucosal immune responses in the mouse, making it a useful tool for studying the modulatory effects of diet.

Reovirus infection increases both the frequency of IgA-producing cells as well as the amount of IgA secreted in PP (19). Secretion of IgA depends upon antigen presentation, activation of B cells by CD4+ T cells, T cell–independent activation of B1 cells, and induction of several cytokines in the intestine (34–36). Reovirus-specific mucosal IgA contributes to the clearance of the virus from the gut (19,29) and has an important role in the protection against reinfection (28,29). In addition, the production of circulating specific IgA, IgG, and IgM enhances protection against the systemic spread of reovirus infection and contributes to immunological memory (20,28,37). Reovirus infection also activates specific cytotoxic CD8+ T-cells, which, along with thymus-independent cytotoxic T cells, protect mucosal sites by lysing virus-infected cells (18). The results presented herein suggest that DHA consumption did not affect Ig responses to reovirus and that the effects of this diet on clearance of the virus from the gastrointestinal tract were transient.

Although consumption of DHA-enriched fish oil did not significantly impact specific IgA secretion in the gut up to 8 d PI, IgA levels were higher in DHA-fed mice than in controls at 10 d PI. Elevated mucosal IgA secretion in DHA-fed mice might similarly be explained as a compensatory response to the heightened PP and intestinal lumen of the virus that was observed. We employed fragment cultures to monitor ex vivo Ig responses to reovirus. Fragment cultures are a useful complement to more cumbersome methods for the detection of such a response (38,39). This approach retains the integrity of the lymphoid tissue and further provides an indication of the overall Ig output for the entire mouse. Although lamina propria cultures derived from DHA-fed mice at 5 d PI secreted more IgA than corresponding controls, IgA production by PP and spleen cultures did not differ among mice fed control or DHA diets. Thus the importance of these small differences observed for fecal IgA and lamina propria secretion is likely to be, at most, modest.

The observations that more viral RNA were detectable in PP at 3 to 7 d PI and in feces from 2 to 6 d PI in DHA-fed mice than in controls suggest that viral clearance was transiently suppressed by the (n-3) PUFA diet. Increased fecal shedding of an enteric virus might increase the potential for it to be transmitted among hosts. The mechanisms for DHA's transient effects on viral clearance are unclear but might involve innate immune responses. Most notably, Type 1 interferon (IFN{alpha} and IFNβ) expression is critical to reovirus clearance in the intestine (40). These cytokines generate an antiviral state and help mediate subsequent adaptive responses. The major source of Type I IFN in PP are resident dendritic cells that take up antigens directly at this site, whereas epithelial or natural killer cells are less important for reovirus clearance (40). Relative to the former, (n-3) PUFA have been shown to suppress both dendritic cell antigen presentation in rats (41) and human dendritic cell maturation in vitro (42). Further investigation is needed to ascertain how (n-3) PUFA alter Type 1 IFN expression and/or affect dendritic cell function and whether these effects impact responses to reoviruses and other enteric viruses.

For virus measurements, we assessed 3 compartments: intestinal lumen (feces), PP, and PP-depleted intestines. RT-PCR was used to analyze feces and PP because of limited sample amounts. The transient elevation and resolution of fecal and PP reovirus L2 RNA observed in DHA-fed mice, contrast with our inability to detect differences in infectious particle numbers among the intestines of control and DHA-fed mice. This discordance possibly suggests that although DHA permitted greater viral RNA replication, there might have been an inadequate concurrent assembly of mature infectious viruses in the intestinal tissues. Alternatively, DHA might enhance turnover of virus-infected epithelial cells thereby shedding more virus into the intestinal lumen. Nevertheless, these effects were transient and the absence of viral RNA in feces at 8 and 10 d PI suggested that, ultimately, the host was capable of controlling the infection.

The potential for (n-3) PUFA to cause immunosuppression and/or impair clearance of infectious microbes has been assessed in models employing both bacterial and viral infections. Feeding with fish oil and infecting with gram-negative bacteria, Klebsiella sp (43), Salmonella sp (44,45), and Pseudomonas aeruginosa (46,47), or the gram-positive bacteria, Staphylococcus aureus (48), group B Streptococcus sp (49), and Listeria monocytogenes (50–52), resulted in contradictory effects ranging from enhancement to suppression of the host survival (53). The capacity of (n-3) PUFA to modulate host resistance appears to depend on the nature of the pathogen, type, and dose of fatty acid, time period of supplementation, and immune endpoint.

Viral models that have been used to estimate the possible modulatory effects of (n-3) PUFA on host resistance include cytomegalovirus, murine retrovirus, and influenza virus. Mice infected with cytomegalovirus and supplemented with fish oil did not show effects on susceptibility to the infection (47). Mice infected with murine retrovirus and fed fish oil for 8 wk had significantly enhanced survival compared with control mice (54). For the same virus, it was observed that serum levels of IgG and IgM were reduced in mice fed fish oil (55). Additionally, fish oil consumption reduced virus induction of tumor necrosis factor-{alpha}, interleukin-1β, and IFN{gamma} during the infection (55). In studies with influenza virus, Byleveld et al. (14) reported that fish oil feeding interfered with viral clearance from lungs and reduced IgA secretion in lungs. Furthermore, IFN{gamma} mRNA expression was found to be downregulated by fish oil supplementation. Thus, as with bacteria, the effects of fish oil administration on the response to virus infection might vary with the type of virus and immune endpoint selected.

Taken together, the results presented here suggest that DHA consumption did not adversely alter mucosal or systemic Ig responses to reovirus. This dietary regimen caused a transient delay in viral clearance from the gastrointestinal tract, but final resolution of the infection appeared to be unaffected. Whereas typical long chain (n-3) PUFA intake recommendations for healthy people range from 0.5 to 2 g/d, higher-level consumption (3 to 12 g/d) has been used for disease prophylaxis and therapy. The combined (n-3) PUFA concentrations in the mouse diets employed in the present study were 40.8 g/kg, which would account for 8.2% of the total energy intake. Upon extrapolation, a human consuming 2000 kcal/d (8.368 MJ/d) would need to consume 18.2 g/d (n-3) PUFA to be comparable with that consumed by the mouse in this experiment [mouse/(kg body weight · d)]. Given the transient nature of the effects observed even at this very high DHA dose, (n-3) PUFA might be predicted to have little effect on Ig responses and clearance of reovirus. Because 1 possible limitation of this study was the use of a single infectious dose, it would be of interest in the future to discern whether DHA consumption has any effect on the minimum infectious dose for this reovirus T1/L. It should be further noted that the reovirus strain employed does not induce a high incidence of morbidity or mortality in adult mice. Therefore, to ascertain whether our findings are translatable to general mucosal immunity, further research is needed on the effects of DHA on mucosal immune responses to other more highly virulent viruses and bacteria known to infect the gut.


   FOOTNOTES
 
1 Supported by Public Health Service grant DK 58833 from the National Institute for Diabetes and Digestive and Kidney Diseases and the Michigan State University Agricultural Experiment Station. Back

2 Author disclosures: E. Beli, M. Li, C. Cuff, and J. Pestka, no conflicts of interest. Back

7 Abbreviations used: DHA, docosahexaenoic acid; DON, deoxynivalenol; EPA, eicosapentaenoic acid; IFN, interferon; IgAN, IgA-nephropathy; PFU, plaque forming units; PI, postinfection; PP, Peyer's patch; reovirus, respiratory enteric orphan virus; T1/L, Type 1 L. Back

Manuscript received 18 October 2007. Initial review completed 4 December 2007. Revision accepted 21 January 2008.


   LITERATURE CITED
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 ABSTRACT
 Introduction
 Materials and Methods
 Results
 Discussion
 LITERATURE CITED
 

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