Vomitoxin-induced dysregulation of serum IgA, IgM and IgG reactive with gut bacterial and self antigens.

The effect of dietary vomitoxin exposure on immunoglobulins that react with naturally occurring gut bacterial and self antigens was assessed in the B6C3F1 mouse. Ingestion of 25 ppm vomitoxin for 4 and 8 wk resulted in significantly elevated total IgA but depressed total IgG and IgM in serum when compared with control mice fed semi-purified diet only. IgA specific for phosphorylcholine (PC) and inulin (haptens associated with intestinal bacteria) increased significantly in mice fed vomitoxin whereas IgM with the identical specificity decreased. When sera were assessed for autoantibodies recognizing DNA and bromelated mouse red blood cells (MRBC), vomitoxin-exposed mice exhibited elevated specific IgA as compared with controls. This occurred together with decreases in DNA-specific IgG and IgM, and decreases in MRBC-specific IgM. Additionally, vomitoxin exposure did not enhance the specific serum IgA response to orally administered trinitrophenylated sheep red blood cells (TNP-SRBC), but significantly depressed TNP-specific serum IgG. The results suggest that hyperelevation of total and specific serum IgA for oral and self antigens occurs during vomitoxin feeding and that may be coupled with down-regulation of total and specific IgM or IgG. These effects could be contributory to the capacity of vomitoxin to induce IgA immune complex glomerulonephritis.     

Dysregulation of IgA production and IgA nephropathy induced by the trichothecene vomitoxin

The effect of dietary exposure to vomitoxin on serum immunoglobulin A (IgA) was evaluated in the B6C3F1 mouse. Levels of serum IgA were elevated maximally in mice fed 25 ppm vomitoxin in comparison with levels in mice fed 2, 10 or 50 ppm vomitoxin. Significant increases were detectable after as few as 4 wk in mice fed 25 ppm vomitoxin, and IgA levels were increased more than 17-fold after 24 wk of toxin exposure. Serum IgA also exhibited a marked shift from primarily monomeric IgA to primarily polymeric IgA during vomitoxin treatment. Serum IgG and IgM decreased in treated mice, suggesting that the effect was isotype-specific. Elevated serum IgA was not observed in mice when control diet was fed at levels equivalent to those consumed by vomitoxin-treated mice, which exhibited feed refusal. IgA production was significantly increased in both spontaneous and mitogen-stimulated splenocyte cultures from mice exposed to vomitoxin in comparison with cultures prepared from ad lib. or feed-restricted controls. Immunofluorescence staining revealed marked accumulation of mesangial IgA and electron microscopy showed electron-dense deposits in the glomeruli of vomitoxin-treated mice but not in those of controls. Dysregulation of IgA production and accumulation of glomerular IgA as observed in this study were highly analogous to the characteristics of human IgA nephropathy, the most common form of glomerulonephritis worldwide.     

Progressive Serum IgE Elevation in the B6C3F1 Mouse Following Withdrawal of Dietary Vomitoxin (Deoxynivalenol)

Vomitoxin (deoxynivalenol) is a fungal toxin that induces serumIgA hyperelevation, IgA autoantibodies, mesangial IgA depositionin mice upon dietary exposure. The capacity of dietary vomitoxinto similarly alter serum IgE was assessed in female B6C3F1 mice.Ingestion of 25 ppm vomitoxin in AIN-76A semipurified diet resultedin 2.7-, 4-, 5-, and 2.3-fold increases in serum IgE relativeto controls after 12, 16, 20, and 24 weeks of toxin feeding,respectively. When mice were fed 25 ppm vomitoxin for 8 weeksand continued on toxin-free diet, serum IgE levels were 2.4,4, 4.9, and 2-fold that of controls at 12, 16, 20, and 24 weeks,respectively. IgE levels were not significantly different betweentreatment and withdrawal groups at Weeks 12–24. Theseresults differed from those of serum IgA, which increased muchearlier and only during toxin administration, and those of IgG,which was largely unaffected compared to controls. The resultsindicate that a defined period of vomitoxin ingestion can subsequentlyinduce progressive dysregulation of IgE production in additionto previously described IgA-related pathologic effects.     

Effect of dietary administration of the trichothecene vomitoxin (deoxynivalenol) on IgA and IgG secretion by Peyer's patch and splenic lymphocytes

Prolonged dietary exposure of mice to the trichothecene vomitoxin induces abnormally high levels of serum IgA and kidney mesangial IgA accumulation in a manner that is highly analogous to the human glomerulonephritis IgA nephropathy. In this study, the capacity of Peyer's patch and splenic lymphocytes to produce IgA and IgG were compared in B6C3F1 mice that were fed diets with and without 25 ppm vomitoxin for up to 12 wk. Serum IgA increased 2-, 4- and 8-fold after 4, 8 and 12 wk, respectively, of vomitoxin exposure and it became the primary serum isotype, whereas serum IgG was unaffected. On termination of the experiment there were increased numbers of IgA-secreting cells in Peyer's patches after 8 wk of toxin exposure and in the spleen after 4, 8 and 12 wk of toxin exposure. There were also increased numbers of IgG-secreting cells in Peyer's patches on termination of the experiment at 4, 8 and 12 wk but no effects was observed in the spleen. Supernatant IgA and IgA-secreting cell numbers were also markedly elevated in lymphocyte cultures obtained from Peyer's patches and, to a lesser extent, from spleens of treated mice compared with controls. Based on output of treated mice relative to corresponding controls, IgA secretion was greatest in concanavalin-A-stimulated and unstimulated Peyer's patch cultures. Enhanced IgG secretion and IgG-secreting cells were also observed in mitogen-stimulated and unstimulated Peyer's patch lymphocyte cultures of treated relative to control mice, but differences in splenocyte cultures were negligible. Based on total Ig output, IgA production was 8- to 20-fold greater than IgG production in both control and treatment Peyer's patch cultures. In contrast, vomitoxin treatment caused a shift from primarily IgG production in lipopolysaccharide-stimulated spleen cultures to equivalent IgA production. These data provide in vitro evidence that ingestion of vomitoxin promotes terminal differentiation of IgA-secreting progenitors in the Peyer's patch and, to a lesser extent, in the spleen. These functional changes are consistent with the shift from IgG to IgA as the primary serum isotype.     

Persistent Dysregulation of IgA Production and IgA Nephropathy in the B6C3F1 Mouse Following Withdrawal of Dietary Vomitoxin (Deoxynivalenol)

To assess whether vomitoxin-induced dysregulation of IgA productionand IgA nephropathy are reversible, relevant immunologic parameterswere compared among experimental groups of B6C3F1 mice thatwere fed: (1) 25 ppm vomitoxin in AIN-76A semipurified dietfor 24 weeks (treatment group), (2) 25 ppm vomitoxin for 8 weeksand then control diet for 16 weeks (withdrawal group), and (3)control diet for 24 weeks (control group). Levels of serum IgAand microhematuria index in the treatment group were elevatedafter 4 to 8 weeks and continued to increase with further vomitoxinexposure. IgA immune complexes and mesangial IgA deposition,as quantitated by interactive laser cytometer image analysis,were also increased with toxin exposure at Weeks 8, 16, and24, whereas IgM, IgG, and complement component C3 depositionwere unaffected or depressed. Serum IgA, microhematuria index,and mesangial IgA deposition in withdrawal mice remained elevatedover those of the controls at Weeks 16 and 24 but were lessthan those of the treatment group. Cell recovery from Peyer'spatches (PP) as well as the percentages of IgA⁺ and CD4⁺ cellsin PP and spleen at Weeks 16 and 24 were greater in treatmentmice than in controls, but only the percentage of IgA⁺ cellsin PP was elevated in the withdrawal mice at these the sametime points. When IgA secretion by unstimulated and LPS-stimulatedsplenic lymphocytes was used as the measure of systemic production,it was elevated in both treatment and withdrawal mice at Weeks16 and 24. The results indicated that experimental dysregulationof IgA production and IgA nephropathy persisted up to 4 monthsafter a discrete period of dietary vomitoxin exposure, but thatthe severity of these effects did not increase in a progressivefashion.     

Effects of intermittent vomitoxin exposure on body weight, immunoglobulin levels and haematuria in the B6C3F1 mouse.

Continuous dietary exposure of female B6C3F1 mice to the trichothecene vomitoxin (VT) results in reduced body weight gain, elevated production of serum immunoglobulin A (IgA), kidney mesangial IgA deposition and glomerulonephritis. To assess whether intermittent consumption of dietary VT, as might occur during natural animal and human exposures, has similar effects to those for continuous consumption, a comparison was made between two schedules of dietary exposure. Female B6C3F1 mice were fed for 13 weeks with either a semipurified AIN-76A diet containing 20 ppm VT continuously or with 20 ppm VT intermittently (every other week). The effect these diets had on body weight gain, serum immunoglobulin (Ig) profile, mesangial Ig deposition and haematuria were assessed and compared with each other as well as with mice fed a control diet. Reduced body weight gains in the treatment groups were seen as early as 2 weeks. After week 4, the mean body weight of the intermittent group appeared higher than the continuous group during the weeks when it was fed a control diet, but dropped to continuous group levels during the weeks they were fed VT. Serum IgA levels in the intermittent group remained at control levels and were significantly lower than the continuous group during the course of the study. In contrast, serum IgG and serum immunoglobulin M (IgM) levels for the intermittent and continuous groups were significantly decreased compared with control. Mesangial IgA deposition was significantly lower in the intermittent group compared with the continuous group, and had levels comparable to mice on the control diet. Haematuria was significantly greater in both treatment groups compared with control at weeks 5 and 13 when the intermittent group was fed VT containing diet, but haematuria in the intermittent group dissipated at week 10 when it was fed control diet. The results presented here suggest that the type of dietary exposure regimen is critical in determining the extent of toxic effects induced by VT. Thus, when animal models are used for assessing the toxic effects of mycotoxins, it may be useful to consider the effects of intermittent and sporadic exposure.     

Effects of vomitoxin ingestion on murine models for systemic lupus erythematosus.

Dietary exposure to the trichothecene vomitoxin (VT) results in reduced body weight gain, elevated serum IgA, terminal differentiation of Peyer's patch B cells to IgA secreting plasma cells haematuria, and increased kidney mesangial IgA accumulation in B6C3F1 mice and other inbred strains. These effects closely mimic a human autoimmune-like kidney disease known as IgA nephropathy. Using NZBW/F1, MRL/lpr, and BXSB mouse strains as models of systemic lupus erythematosus, we assessed whether consumption of diet containing 5 ppm or 10 ppm VT will similarly affect mice genetically prone to autoimmunity. Reduced weight gains were seen in NZBW/F1 and MRL/lpr mice fed both doses of VT within 2-3 weeks. In contrast, VT had little effect on weight gain by BXSB mice. Serum Ig levels in all three strains generally did not differ from control mice. Haematuria was significantly increased when all three strains were fed VT. In NZBW/F1 Peyer's patch cultures stimulated with lipopolysaccharide (LPS), prior VT exposure significantly increased the IgG and IgM secretion but had no effect on IgA. In MRL/lpr Peyer's patch cultures stimulated with LPS, VT exposure increased IgA secretion but not IgM or IgG. BXSB Peyer's patch cultures prepared from VT treatment groups produced significantly more IgA than controls when cultured with LPS or Concanavalin A. Whereas mesangial deposition of IgA and IgG was significantly lower in the treatment groups of NZBW/F1 and MRL/lpr mice compared with control, BXSB mice had significantly higher IgA, IgG, and complement (C3) deposition when fed VT. The results suggest that although dietary VT differentially affected mice with aberrant immune systems, these strains did not appear to be any more sensitive to the mycotoxin than were more immunologically robust inbred strains.     

Dietary exposure to the trichothecene vomitoxin (deoxynivalenol) stimulates terminal differentiation of Peyer's patch B cells to IgA secreting plasma cells

The effects of 8 weeks of dietary exposure to the fungal toxin vomitoxin (25 ppm) on the kinetics of in vitro immunoglobulin (Ig) production and appearance of IgA-secreting cells in lymphocyte culture were assessed in the B6C3F1 mouse. The feeding regimen resulted in an IgA:IgG serum ratio of 2.4 compared to 0.4 in controls indicating that there was dysregulation of IgA production in the systemic compartment. Prior toxin feeding had no effect on viability of Peyer's patch (PP) or splenic lymphocyte cultures. IgA production, as determined by enzyme-linked immunosorbent assay, was significantly greater in treatment PP and splenic lymphocytes cultured for 2-11 days than in corresponding controls. Similar trends were found for IgG production in PP cultures although levels were much lower. There were 1.7 and 2.0 times more IgA-producing cells, as measured by the ELISPOT assay, in freshly prepared PP and splenic lymphocytes from treatment mice compared to control mice, respectively. In contrast, after 2 days there were 10.9, 3.2, and 12.4 times more IgA-secreting cells in concanavalin A (Con A), LPS, and unstimulated treatment PP cultures, respectively, and 4.0, 2.0, and 3.5 times times more IgA-secreting cells in 2-day treatment spleen cultures, respectively. Both IgA and IgG secretion in Con A-stimulated cultures were significantly greater when treatment T cells and control B cells were combined than when control T cells and control B cells were combined. Increased Ig secretion attributable to T cell effects was not observed in LPS-stimulated or unstimulated PP reconstitution cultures or in spleen reconstituted cultures with and without mitogen. The results provide evidence that dietary vomitoxin enhances terminal differentiation of IgA secreting cells in PP. This and resultant migration of IgA secreting cells into the systemic compartment favor a shift from IgG to IgA as the primary serum isotype.     

Effects of Dihydrotestosterone and Estradiol on Experimental IgA Nephropathy Induced by Vomitoxin

Ingestion of the trichothecene vomitoxin (VT) by mice induceseffects that mimic the common human glomerulonephritis, IgAnephropathy (IgAN). These include elevation of serum IgA, IgAimmune complexes, and mesangial IgA deposition. Based on previousobservations that male mice are more prone to VT-induced IgAN,the effects of castration of male and female B6C3F1 mice andsex hormone supplementation on several immunopathologic indicatorsof the disease were compared. In the first study, castratedand intact male and female mice were fed control AIN-76A dietor the same diet containing 10 ppm VT for 12 weeks. At Week12, all but the intact female group fed VT exhibited increasedserum IgA, with castrated female mice having greater levelsthan intact females. When microscopic hematuria was used asan indicator of disease severity in intact VT-fed mice, erythrocytecounts for males exceeded those for females at weeks 4 and 12.VT-fed, castrated females exhibited greater hematuria than intactcounterparts, whereas VT-fed, castrated males had lower urinaryerythrocyte counts than intact counterparts. In a second study,castrated male and female mice were implanted with controlledrelease pellets of placebo, 5-dihydrotestosterone (DHT), or17ß-estradiol (E₂) and then were fed either controldiet or a 10 ppm VT diet for 8 weeks. Castrated male and femalemice treated with VT and DHT pellet exhibited more severe hematuria,higher IgA levels, and greater mesangial IgA deposition thanmice exposed to the same diet with placebo or E₂ pellet at Week8. While VT-fed animals with an E₂ pellet exhibited greaterhematuria and mesangial IgA deposition at Week 8 than the placebogroups, their IgA levels were not significantly elevated overthose for VT-fed mice with a placebo pellet. Relative to twoother pathologic markers for IgAN, the aforementioned effectsin both studies were generally consistent with mesangial depositionof complement component C₃ but not IgG. The results suggestthat (1) enhanced male susceptibility to VT-induced IgAN maybe related to modulation by the biologically active androgenDHT and (2) while castration of females increased severity ofVT-induced IgAN, supplementation of castrated male or femalemice with E₂ did not reverse this effect but rather increaseddisease severity.     

Quantitative Assessment of Mesangial Immunoglobulin A (IgA) Accumulation, Elevated Circulating IgA Immune Complexes, and Hematuria during Vomitoxin-lnduced IgA Nephropathy

Quantitative Assessment of Mesangial Immunoglobulin A (IgA)Accumulation, Elevated Circulating IgA Immune Complexes, andHematuria during Vomitoxin-lnduced IgA Nephropathy. Dong, W.,Sell, J. E., and Pectka, J. J. (1991). Fundam. Appl. Toxicol.17,197-207. Extended dietary exposure to the trichothecene vomitoxin(deoxynivalenol), a naturally occurring fungal contaminant ofcereal grains, induces elevated serum IgA and mesangial IgAaccumulation in a manner similar to the human glomerulonephritis,IgA nephropathy. A 12-week feeding study was conducted in theB6C3F1 mouse to evaluate the effects of exposure to 25 ppm dietaryvomitoxin over time on formation of IgA immune complexes (IgA-IQ,hematuria, and mesangial deposition of IgA, IgG, IgM, and complementcomponent C3. Both serum IgA and IgA-IC were significantly elevatedin vomitoxin-exposed treatment groups compared to controls atweeks 4, 8, and 12, whereas serum IgG was unaffected. The incidenceof hematuria was also significant in vomitoxin-exposed miceat weeks 4, 8, and 12. Quantitative immunofluorescence intensitymeasurements using interactive laser cytometer image analysisrevealed significantly greater mesangial IgA accumulation invomitoxin-fed mice compared to controls at weeks 4,8, and 12.Although glomerular IgG and IgM deposition was present in bothcontrols and treated mice, it was significantly lower in treatedmice as compared to controls at week 12. Mesangial C3 depositionwas not induced by vomitoxin feeding. Elevated IgA-IC, hematuria,and IgA mesangial accumulation occurring during exposure tovomitoxin mimicked human IgA nephropathy, whereas the absenceof mesangial C3 represented a major difference between thistoxin-induced immune deregulation and the human disease.     

Elevated membrane IgA+ and CD4+ (T helper) populations in murine Peyer's patch and splenic lymphocytes during dietary administration of the trichothecene vomitoxin (deoxynivalenol)

Recent investigations indicate that dietary exposure to the trichothecene vomitoxin increases total and antigen-specific serum immunoglobulin A (IgA) and glomerular IgA accumulation in mice. In this study, the effects of 25 ppm dietary vomitoxin on the histological and lymphocytic profile of component immune organs in the mucosal lymphocyte migratory pathway were evaluated in the B6C3F1 mouse. Vomitoxin administration resulted in marked stimulation of the size and frequency of germinal centres in Peyer's patches, mesenteric lymph nodes and the spleen. A slight increase in the percentage of B cells in the Peyer's patch was observed, although vomitoxin treatment had no effect on the percentage of B cells in the spleen. The percentage of IgA+ cells in Peyer's patches and spleen were approximately twice that of controls at 4, 8 and 12 wk of vomitoxin exposure whereas the percentage of IgG+ cells decreased in these two organs. Exposure to vomitoxin increased the percentage of T cells in Peyer's patches and the spleen. The percentage of CD4+ cells (T helper subset) increased slightly in Peyer's patches and more markedly (30-50%) in the spleen following vomitoxin treatment. Contrastingly, there was only a slight increase in the percentage of CD8+ cells (T cytotoxic/suppressor subset) in the spleens of vomitoxin-treated mice in comparison with controls, and no effect in Peyer's patches. The relative effects of vomitoxin on these two T cells populations was also reflected in increased CD4+: CD8+ ratios in Peyer's patches and spleen. These results are consistent with the hypothesis that dietary vomitoxin modulates normal regulation of the IgA response at the Peyer's patch level and that this is manifested in an altered lymphocyte distribution pattern in both the mucosal and systemic compartment. Notably increased levels of IgA+ and CD4+ cells are indicative of IgA-producing progenitors and T helper subsets, respectively, that in tandem could favour IgA hyperproduction and elevated IgA in serum.     

Experimental Murine IgA Nephropathy following Passive Administration of Vomitoxin-induced IgA Monoclonal Antibodies

Oral exposure of mice to vomitoxin (VT) induces elevated levels of serum IgA, circulating IgA immune complexes (IgA-IC), mesangial IgA deposition and haematuria, which all mimic the clinical signs of human IgA nephropathy (IgAN). To further assess the effects of VT-induced IgA in the murine model, B6C3F₁ and BALB/C mice were injected intraperitoneally with affinity-purified monoclonal IgA derived from Peyer's patch hybridomas of VT-exposed mice. In B6C3F₁ mice, serum IgA, IgM and IgA-IC levels were increased two- to fivefold in treatment groups after 4 and 6 wk compared with controls, whereas increases in serum IgG as high as 18-fold were observed. Urinary erythrocyte counts were also significantly elevated in treatment groups after 2, 4 and 6 wk compared with controls. Concurrent increases in IgA and IgG complexes containing casein, the dietary protein source, occurred in treatment mice. Mesangial IgA, IgG, IgM and C3 deposition were significantly increased in all treatment mice after 6 wk. Electron-dense deposits occurred in the glomeruli of IgA-injected mice after 6 wk. All the above parameters were similarly affected in BALB/C mice. Injection of IgA-secreting hybridoma cells into BALB/C mice increased serum IgA, IgA-IC and IgG levels as well as elevated mesangial IgA, IgG and C3 deposition and haematuria after 2–3 weeks compared with controls. In total, these data indicate that passive administration of VT-induced IgAs can induce the hallmarks of IgA nephropathy. Casein, an antigen found in the diet used for these mice, appeared to form IC with IgA or IgG and these IC may participate in the pathogenesis of this nephropathy.     

Interleukin-6-deficient mice refractory to IgA dysregulation but not anorexia induction by vomitoxin (deoxynivalenol) ingestion.

Dietary exposure to the trichothecene vomitoxin (VT) causes feed refusal and elevates IgA production in the mouse. Based on the observations that IL-6 can cause anorexia and promote IgA production and that gene expression of this cytokine is increased in vivo and ex vivo on VT exposure, we hypothesized that IL-6 is an essential cytokine in VT-induced feed refusal and IgA dysregulation. To test this hypothesis, the effects of dietary VT on feed intake, weight gain, serum IgA levels and kidney mesangial IgA deposition in an IL-6-"knockout" mouse (B6129-IL6(tmi Kopf)) were compared to those in both a corresponding "wildtype" (B6129F2) and a previously characterized "sentinel" strain (B6C3F1) that possess the intact gene for this cytokine. IL-6 deficiency did not alter the capacity of VT to cause feed refusal or impair weight gain. VT-fed B6129F2 and B6C3F1 mice had significantly higher serum IgA concentrations than did their corresponding controls fed clean diet, whereas significant differences were not observed between IL-6 KO mice fed VT or control diets. Kidneys taken from VT-fed wild-type and sentinel mice had significantly increased mesangial IgA deposition as compared to controls. While slight increases in mesangial IgA were observed in VT-fed IL-6 KO mice, mean fluorescence intensities were significantly less than that found in the corresponding wild-type and sentinel strains. IL-6 KO mice appeared to be less prone to the development of microscopic haematuria following VT exposure than were the corresponding wild-type and sentinel strains. In total, the results suggested that IL-6-deficient mice were refractory to VT-induced dysregulation of IgA production and development of IgA nephropathy, whereas chronic VT-mediated nutritional effects related to feed intake and weight gain were unaffected.     

Subchronic toxicity of vomitoxin in Sprague-Dawley rats

Purified vomitoxin was incorporated into the diet at a level of 20 ppm and fed to male Sprague-Dawley rats ad lib. for 90 days. Few clinical signs of toxicity were observed. Rats in the vomitoxin treatment group were less efficient in converting feed into body mass, but there was no feed refusal. Terminal body weight was reduced in the vomitoxin treatment group. There were no statistically significant effects on serum enzyme levels, haematological parameters or tissue lesions, or on liver detoxification systems, as reflected in levels of microsomal cytochrome P-450 or in glutathione S-transferase activity.     

灌洗法检测减毒鼠伤寒杆菌疫苗对幽门螺杆菌的免疫应答

目的应用高渗灌洗液法(灌洗法)检测表达幽门螺杆菌(Hp)尿素酶B亚单位(UreB)的减毒鼠伤寒杆菌活菌重组疫苗口服免疫小鼠后的免疫应答状况。方法将能表达UreB的重组减毒鼠伤寒杆菌SL326l/pTC01-UreB口服免疫Balb/c小鼠,12周后应用灌洗法或将小鼠处死直接获取小鼠肠液,检测小鼠的肠液和血清中针对UreB的特异性IgA和IgG抗体反应。结果疫苗组小鼠的肠液和血清中可分别检测到针对UreB的特异性IgA和IgG抗体,与对照组存在显著性差异(P<0.01)。灌洗法获取的小鼠肠液中的IgA抗体含量较将小鼠处死后直接获取的肠液中的IgA抗体含量明显为高(P<0.01)。病理学检查显示疫苗组小鼠胃粘膜炎症指数无改变。结论高渗灌洗液法是获取肠道抗体的理想方法;表达HpUreB的减毒鼠伤寒杆菌SL326l/pTC01-UreB可用作抗Hp感染的口服疫苗。     

Increased IgA and IgG serum levels using a novel yam-boxthorn noodle in a BALB/c mouse model.

To determine whether yam-boxthorn noodle, a newly developed functional noodle, has immunomodulatory effects in vivo, we measured the changes in visceral organ weight, immunoglobulin (Ig) A, IgE, IgG, IgM serum level and IgA level in the intestinal lavage fluid of female BALB/c mice after continuously consuming the test diet for 5 weeks. We found that body weights and absolute and relative organ weights (lung, heart, liver, spleen and kidney) in female BALB/c mice did not significantly change compared with those from the control group. The IgA and IgG serum levels in the experimental group significantly increased in a dose-dependent manner when the yam-boxthorn noodle concentration in the AIN 76 diet rose from 3% to 30%. However, the IgE and IgM level in the serum and the IgA level in the intestinal lavage fluid did not significantly change. These experiments demonstrate that the functional noodle, yam-boxthorn noodle, exhibits immunomodulatory effects in vivo with increasing serum antibody levels, especially in IgA and IgG. These results are valuable for future nutraceutical and immuno-pharmacological use.     

CpG oligodeoxynucleotide synergizes innate defense regulator peptide for enhancing the systemic and mucosal immune responses to pseudorabies attenuated virus vaccine in piglets in vivo

Oligonucleotides containing CpG motifs (CpG ODN) are strong adjuvants for humoral and cellular immune responses in mice, and innate defense-regulator peptides (IDRs) are known to facilitate the uptake of antigens into antigen presenting cells (APCs), but data on synergistic effects of CpG and IDRs in piglets are scarce. In this report, the combination of porcine-specific CpG ODN and HH2 (a kind of IDR which was selected for its better synergy with CpG ODN) was used as immunoadjuvant to enhance the immune responses of the newborn piglets to Pseudorabies attenuated virus (PRV) vaccine. The titers of specific antibodies and serum IgG1/IgG2 subtypes to PRV vaccine, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-12 and IL-4 were examined to identify the immune responses of the newborn piglets. The results showed that piglets immunized intranasally (IN) and subcutaneously (SC) with PRV vaccine and CpG-HH2 complex both presented high titers of PRV-specific antibodies and IgG2 isotype, a Th1-dominated (IFN-γ and IL-12) cytokine profiles, high levels of IgA in saliva, broncheoalveolar lavage (BAL) and intestinal washings. The results suggested that, CpG-HH2 complex augmented systemic (IgG in serum) and mucosal (IgA in saliva, BAL and intestinal washings) immune responses against antigen. CpG-HH2 complex stimulated both T-helper type1 (Th1) (IgG2) and Th2 (IgA) responses when delivered IN, and IN route could induce stronger mucosal immune responses than SC route. All these data indicate that CpG-HH2 complex is a potential effective adjuvant for the PRV vaccine in newborn piglets.     

Effect of dietary whey protein concentrate on primary and secondary antibody responses in immunized BALB/c mice

Proteins derived from the whey fraction of bovine milk are known to modulate immune responses. We have previously described a rennet whey protein concentrate (WPC) that can boost intestinal tract antibody responses to orally administered T-dependent antigens. In the present study, we investigated the effects of feeding WPC to mice on specific antibody responses to several orally or parenterally administered antigens, including influenza vaccine, diphtheria and tetanus toxoids, poliomyelitis vaccine, ovalbumin and cholera toxin sub-unit. WPC-fed mice produced elevated levels of antigen-specific intestinal tract and serum antibodies against all tested antigens, compared to mice that were fed a standard chow diet. Both primary and secondary intestinal tract antibody responses were elevated by WPC feeding, while only secondary serum responses were increased in WPC-fed mice. Significant up-regulation of intestinal tract antibody was observed within 2 weeks of primary oral immunizations. A period of pre-feeding with WPC, prior to commencement of immunization, did not alter the kinetics or magnitude of immune enhancement. These results identify bovine WPC as a potentially important dietary protein supplement, capable of enhancing humoral immune responses to a range of heterologous antigens.     

Effects of deoxynivalenol (vomitoxin) on the humoral and cellular immunity of mice

Sublethal doses (0.00, 0.25, 0.50 and 1.00 mg/kg b.w./day) of vomitoxin (deoxynivalenol; DON) were studied for their effects on humoral and cellular immunity and serum proteins of inbred, male Swiss Webster mice in a series of 4 separate experiments. Vomitoxin was added to basal diet (less than the detection limit, i.e., less than 0.05 micrograms of vomitoxin per g of feed) and administered to mice for 5 weeks beginning at 21 days of age. Mice in experiment 2 were fed the basal diet for 40 days in addition to the 5-week treatment with vomitoxin. The 1.00 mg/kg dose of vomitoxin resulted in a statistically significant reduction in the serum levels of alpha 1 and alpha 2-globulins, an increase in total serum albumin, and a reduction in feed consumption and body weight gain compared to the control group. The 0.50 mg/kg dose of vomitoxin resulted in significantly reduced serum levels of alpha 2- and beta-globulins while a significant reduction of feed consumption was evident only during Week 4. Similarly, body weight gain in this group of mice was significantly reduced during Week 2 but increased to normal levels during Week 3 and remained parallel to the control for Week 4 and 5. Both levels (0.50 and 1.00 mg/kg) of vomitoxin resulted in a reduced, dose-related, time-to-death interval following a challenge with L. monocytogenes and increased proliferative capacity of splenic lymphocyte cultures stimulated with the phytohemagglutinin P (PHA-P) mitogen compared to the control group of mice. The 0.25 mg/kg dose of vomitoxin did not have any significant effects on the parameters studied. A reasonable estimation of a 'no effect' level for immunologic effects in mice based on these and previous immunological studies would seem to be between 0.25 and 0.50 mg/kg b.w./day.     

Influence of dietary polybrominated biphenyl on antibody and host defense responses in mice

Male $\text{Balb}\text{cByJ}$ mice were fed diets containing 5 or 167 ppm of polybrominated biphenyls (PBB) (Firemaster, FFl, lot No. 7042) for either 3 or 6 weeks and then evaluated for their ability to produce antibody and to resist a challenge with malaria or endotoxin. Animals which received a dietary exposure of either 5 or 167 ppm of PBB for 3 or 6 weeks manifested no alteration in their resistance to a challenge infection with Plasmodium berghei (NYU-2), a lethal murine malaria parasite. However, mice which were fed a diet containing 167 ppm of PBB for 3 or 6 weeks had a significant increase in endotoxin (LPS) sensitivity while no change in LPS sensitivity was observed in mice fed 5 ppm of PBB. Peak primary antibody production to sheep erythrocytes, expressed as $\text{PFC}\text{10}{}^{\mathrm{<mtext>6</mtext>}}$ spleen cells, was reduced almost 50% in mice fed a diet containing 167 ppm for 3 weeks, however, no change in $\text{PFC}\text{10}{}^{\mathrm{<mtext>6</mtext>}}$ cells was observed at 6 weeks. A dietary level of 5 ppm of PBB did not alter primary antibody formation at either 3 or 6 weeks. The peak secondary PFC response in both 5- and 167-ppm-treated groups was delayed by 1 day, relative to control values. $\text{PFC}\text{10}{}^{\mathrm{<mtext>6</mtext>}}$ cells, measured on the day of the peak control response, were depressed 60% at 3 weeks and over 85% at 6 weeks at both doses. Serum IgM levels in the mice receiving 167 ppm of PBB were reduced 23–63% during the I° and II° responses, serum IgG was only moderately reduced and serum IgA was unaltered throughout the study. These results suggest that PBB has a minimal effect on antibody production to T-dependent antigens or on host defense to protozoan parasites yet causes a selective depletion of serum immunoglobulin isotypes. The marked increase in LPS sensitivity suggests a compromised macrophage detoxification capability.