Immune response to ovalbumin following bisphenol A administration in mice fed with a low level of dietary protein.

BACKGROUND AND PURPOSE: We have previously shown that bisphenol A (BPA) augments T-helper (Th) 1 activity with no significant effects on an established oral tolerance to ovalbumin (OVA) in mice fed with a normal protein diet. The present study aimed to examine the effect of BPA on the immune response in a mouse model maintained on a very low protein diet (5% casein). METHODS: Mice were fed on a 5% protein diet, together with either OVA (OVA-fed) or water (water-fed), immunized intraperitoneally with OVA at 3-week intervals and administered BPA between the 2 immunizations. A week after the last immunization, animals were sacrificed and examined by enzyme-linked immunosorbent assay for serum titers of total immunoglobulin E (IgE), OVA-specific IgE, immunoglobulin G (IgG), IgG1, IgG2a, and the production of interferon-gamma, interleukin (IL)-4, and IL-12. RESULTS: In both BPA-treated and non-treated animals, OVA feeding resulted in lower titers of total and OVA-specific IgE, and OVA-specific IgG (p<0.05). There were higher levels of interferon-gamma (p<0.05), IL-4, and IL-12 (p<0.05) in animals with OVA tolerance following BPA treatment. However, IL-12 production was augmented only in BPA-treated water-fed animals (p<0.01). CONCLUSION: BPA administration in mice fed with a low level of dietary protein augmented Th1 cytokines more profoundly in the animals with OVA tolerance than in the non-tolerant animals.     

Regulation of intestinal immunity by dietary fatty acids

Dietary fatty acids are absorbed through the intestine and are fundamental for cellular energy provision and structural formation. Dietary fatty acids profoundly affect intestinal immunity and influence the development and progression of inflammatory bowel disease, intestinal infections and tumors. Although different types of fatty acids exert differential roles in intestinal immunity, a western diet, rich in saturated fatty acids with abundant carbohydrates and studied as high-fat diet (HFD) in animal experiments, disturbs intestinal homeostasis and plays a pathogenic role in intestinal inflammatory diseases. Here, we review recent findings on the regulation of intestinal immunity by dietary fatty acids, focusing on HFD. We summarize HFD-altered immune responses leading to susceptibility to intestinal pathology and dissect the mechanisms involving the impact of HFD on immune cells, intestinal epithelial cells and the microbiota. Understanding the perturbation of intestinal immunity by HFD will provide new strategies for prevention and treatment of intestinal inflammatory diseases.     

EB病毒蛋白对免疫球蛋白产生的调节作用

目的检验EB病毒(Epstein-Barr Virus,EBV)蛋白对培养的人B细胞产生免疫球蛋白(Immunoglobulin,Ig)的影响.方法用UV灭活和热处理的EBV刺激培养的人脐带血B细胞,流式细胞仪检测UV灭活EBV组细胞CD5、CD3、CD4和CD8的表达,ELISA法检测培养上清中IgG和IgM,同时与EBV转化B细胞产生的IgG和IgM 作对比.结果第14天未检测到T细胞,CD5+B 细胞占43%;28天时CD5+B细胞占47%.UV灭活EBV组第10、18、22和26天IgG A值与对照组相比有显著差异(P＜0.05),第10天以后各时间点IgM A值与对照组相比有显著差异(P＜0.05).EBV转化培养B细胞40天,IgG和IgM A值与同期其它各组有显著差异(P＜0.05).结论EBV蛋白有诱导Ig产生的作用.     

Abnormal immunoglobulin G subclass production in response to keyhole limpet haemocyanin in atopic patients.

A proportion of patients with atopic dermatitis have elevated serum levels of IgG4. In order to investigate further this abnormality of IgG subclass production, atopic patients were immunized with the protein antigen keyhole limpet haemocyanin (KLH), and IgG subclass responses following primary and secondary immunization were analysed. In the primary response, titres of IgG1, 2 and 3 antibodies were lower in the atopic patients than in the controls. In contrast, titres of IgG4 were much higher for the patient group. In both patients and controls, the kinetics of IgG4 antibody production following the initial immunization with KLH showed a slow rise reaching a peak at 30 weeks. This time course indicated that the high IgG4 response was unlikely to be due to previous exposure of the patients to a cross-reacting antigen. A higher proportion of IgG4 was also seen in the atopic patients following secondary immunization; indeed, IgG4 was the major subclass in the secondary response in the patient group. In the controls, but not in the patients, titres of IgG4 anti-KLH correlated with total serum levels of IgG4, and some of the highest IgG4 antibody responses were detected in atopic patients whose serum IgG4 concentration was in the normal range. The results suggest that raised serum levels of IgG4 in atopy may reflect abnormal isotype regulation in response to protein antigens.     

Periodontal bone loss and immune response to ovalbumin in germfree rats fed antigen-free diet with ovalbumin.

A technique for the characterization of rat gingival lymphocytes has been described. The technique was used to obtain gingival cells from rats maintained on antigen-free diets or such diets with ovalbumin (OVA) added. Increases in gingival lymphocyte numbers in the antigen-fed (AF) animals occurred by 16 to 23 days of OVA feeding. The elevated gingival lymphocyte numbers were predominantly T lymphocytes at the initial intervals of the experiment (to 59 days of OVA feeding). At 128 days of OVA feeding T-lymphocyte numbers diminished but B-lymphocyte numbers increased, and AF animals had more than six times as many gingival B lymphocytes as animals not fed antigen. Also, AF animals showed immunoglobulin A antibody in intestinal perfusates (after 9 days of OVA feeding) and in saliva (within 23 days of OVA initiation). Plasma immunoglobulin G antibodies were not detected until 59 days of feeding. Spleen cells from AF rats showed in vitro blastogenic responses to OVA at 23 to 59 days of feeding. Periodontal bone loss was greater in AF animals after 59 and 128 days of OVA. Germfree animals fed only one antigen experienced more periodontal bone loss than animals fed the same diet not containing antigen. Therefore, immune phenomena can contribute to experimental bone loss in germfree rats.     

Prolonged and preferential production of polymeric immunoglobulin A in response to Streptococcus pneumoniae capsular polysaccharides.

Streptococcus pneumoniae is an invasive mucosal pathogen for which host defense is dependent on capsular polysaccharide-specific antibody. Capsule-specific immunoglobulin G (IgG), IgM, and IgA are produced following pneumococcal vaccination and infection. Serum IgA has two molecular forms, polymeric and monomeric. These forms may modulate the avidity of antigen binding and evolve over time as the immune response matures. Therefore, we sequentially characterized the molecular forms of serum IgA to three serotypes of pneumococcal capsular polysaccharides (types 8, 12F, and 14) after pneumococcal vaccination and after natural infection with type 14 S. pneumoniae. Although typically the form of IgA in antigen-specific systemic responses to protein antigens is predominantly polymeric in sera of patients shortly after exposure and shifts to the monomeric form in sera obtained several weeks later, the form of IgA in response to each pneumococcal capsular polysaccharide remained predominantly polymeric 1 month after natural infection and up to I year following vaccination. In contrast, IgA to pneumococcal cell wall polysaccharide was both polymeric and monomeric. Moreover, the form of IgA in response to polyribosyl-ribitol-phosphate (PRP), the capsular polysaccharide of Haemophilus influenzae type b, was predominantly monomeric in the sera of 8 of 10 subjects tested 1 to 3 months after vaccination with either PRP alone or the diphtheria toxoid conjugate of PRP. We conclude that systemic responses to pneumococcal capsular polysaccharides are distinct in the production of predominantly polymeric IgA over time. The persistence of polymeric IgA may facilitate binding and clearance of pneumococci from the systemic circulation or reflect limited maturation of the immune response to pneumococcal capsular polysaccharides.     

Vasoactive intestinal peptide stimulates immunoglobulin production and growth of human B cells.

The effect of vasoactive intestinal peptide (VIP) on human lymphoblastoid B cell lines and tonsil B cells was studied. VIP increased immunoglobulin production and proliferation by lymphoblastoid B cell line, GM-1056, in a dose-dependent manner. As little as 10(-12) M of VIP was effective, and higher concentrations of VIP induced an approximately five-fold increase in IgA production. Moreover, this enhancement was blocked by VIP antagonist. Similarly, VIP enhanced IgM and IgG production by other lymphoblastoid B cell lines, CBL and IM-9, respectively. In contrast to VIP, another neuropeptide substance P (SP) or somatostatin failed to enhance immunoglobulin production and thymidine uptake. VIP also enhanced IgA production and thymidine uptake by purified tonsil B cells. However, in contrast to B cell lines, VIP failed to enhance IgM and IgG production by tonsil B cells. SP or somatostatin failed to enhance immunoglobulin production or thymidine uptake by tonsil B cells. These results indicate that VIP acts as B cell stimulatory factor and that VIP may also have preferential effect on IgA production on tonsil B cells.     

Effect of antigen form on local immunoglobulin A memory response of intestinal secretions to Shigella flexneri.

An enhanced memory response, as shown by increased titers of specific immunoglobulin A (IgA), was seen in intestinal secretions from isolated Thiry-Vella loops in rabbits primed orally with live, locally invasive Shigella sp. X16 and challenged 60 days later with a single oral dose of the same antigen. Heat-killed shigella preparations, when used as either the priming or challenge antigen, did not elicit such a memory response in this system. In the present study, the role of antigen form and dosage in eliciting the enhanced local IgA response was investigated. A noninvasive strain, Shigella flexneri 2457-0, was capable of significantly enhancing the mucosal IgA memory response, whereas heat-killed Shigella sp. X16 was unable to augment the local IgA response, even when the priming dose was increased 100-fold. A proposed mucosal adjuvant, DEAE-dextran, given orally with live Shigella sp. X16, did not enhance the local IgA response. Viable, noninvasive shigellae were effective priming agents in enhancing the local IgA memory response. The poor mucosal response to heat-killed shigella preparations is thought to be related to an ineffective delivery of nonviable bacterial antigens into gut-associated lymphoid tissues. The ability of the live, noninvasive strain to elicit a vigorous local IgA memory response when given orally to rabbits was consistent with previous findings that live preparations elicit the best mucosal IgA response.     

Regulation of immunoglobulin E production in mice immunized with an extract of Toxoplasma gondii.

Repeated infection with Toxoplasma gondii could not induce immunoglobulin E (IgE) antibody production. When mice were injected intraperitoneally twice over a 3-week interval with an extract of tachyzoites of T. gondii and Al(OH)3 as adjuvant, antitoxoplasma IgE antibody was produced. Antitoxoplasma IgE antibody titers were low and diminished after a short time in B10.S, BALB/c, C3H, and C57BL/6 mice. This tendency was more evident in IgE low-responder SJL mice. IgE-inducing activity of Toxoplasma antigen was weaker than those of keyhole limpet hemocyanin, ovalbumin, and an extract from Nippostrongylus brasiliensis. The antitoxoplasma IgE antibody production was enhanced by and persisted after whole-body irradiation (150 R) following secondary immunization. The enhanced antitoxoplasma IgE antibody production was suppressed by transferring spleen cells from Toxoplasma antigen-immunized mice. The suppressive effect of the spleen cells was Toxoplasma antigen specific and was removed by treatment with anti-Thy-1.2 and complement. These results indicate that the low IgE production induced by Toxoplasma antigen is the result of irradiation-sensitive and antigen-specific suppressor T cells. These findings might explain the lack of IgE antibody response in mice with Toxoplasma infection.     

Regulation of the immune response in Plasmodium falciparum malaria: IV. T cell dependent production of immunoglobulin and anti-P. falciparum antibodies in vitro.

T cells from patients with acute Plasmodium falciparum malaria were investigated for induction of immunoglobulin- or anti-malaria antibody secretion in vitro. Stimulation of autologous T/B cell mixtures (2T:1B) with low concentrations of P. falciparum antigen and cultured for 12 days gave rise to a T-dependent IgG secretion which was significantly elevated over that in medium controls. This was achieved with both a crude P. falciparum antigen and a partially purified preparation enriched in Pf 155, a merozoite-derived antigen deposited in the red cell membrane at invasion (Perlmann et al., 1984). Control antigen (RBC ghosts) induced IgG secretion only when added at high concentrations (greater than 10 micrograms/ml). Neither of the antigens induced IgG secretion at concentrations of less than or equal to 10 micrograms/ml in control cultures of lymphocytes from patients with P. vivax malaria. Supernatants from cultures of P. falciparum patients frequently contained anti-P. falciparum antibodies when nanogram quantities (10-100 ng/ml) of either one of the two malaria antigen preparations was used for stimulation. No anti-P. falciparum antibodies were induced by the control antigen at any concentration. The induced anti-P. falciparum antibodies were directed to intracellular parasites and. at lower frequencies, to Pf 155 as detected on the surface of infected erythrocytes. The induction in vitro of anti-P. falciparum antibodies appeared to be correlated with the presence of such antibodies in the sera of the lymphocyte donors. The lymphocytes of only one out of eight P. vivax patients responded to antigen stimulation by secreting anti-P. falciparum antibodies. However, this donor (but not any of the others), was also P. falciparum seropositive. Taken together, these results indicate that the induction of anti-P. falciparum antibody secretion reflects a secondary response in vitro of cells primed in vivo. The present experimental system should be well suited to map parasite antigen for their capacity to induce T cell dependent responses in P. falciparum malaria.     

The humoral immune response of mice to intra-mammary immunization with ovalbumin.

Groups of lactating mice were immunized intra-mammarily on the second day of lactation with 20 micrograms, 150 micrograms or 400 micrograms of ovalbumin (OVA). This resulted in the appearance of IgG in serum, and IgA and IgG in milk. In serum, no IgA antibodies were detected 16 days after immunization in any of the groups. The serum response of IgG was variable and not related directly to the immunizing dose. Both IgA and IgG antibodies were absent in milk 5 days after immunization and IgG antibody level in milk increased significantly throughout lactation as measured 10 and 15 days after inoculation. No IgA antibodies appeared in the milk of the 20 micrograms and 150 micrograms group; however, responses appeared in milk with the highest dose (400 micrograms), but the number of responders for IgG increased in milk but not in blood. The results suggest that intra-mammary immunization can provoke a local IgA response in milk, and that serum is not a major source of IgG in that fluid. Moreover, the kinetics of the IgA and IgG responses differ.     

Saccharomyces boulardii stimulates intestinal immunoglobulin A immune response to Clostridium difficile toxin A in mice

Saccharomyces boulardii is a nonpathogenic yeast that protects against antibiotic-associated diarrhea and recurrent Clostridium difficile colitis. The administration of C. difficile toxoid A by gavage to S. boulardii-fed BALB/c mice caused a 1.8-fold increase in total small intestinal immunoglobulin A levels (P = 0.003) and a 4.4-fold increase in specific intestinal anti-toxin A levels (P < 0.001). Enhancing host intestinal immune responses may be an important mechanism for S. boulardii-mediated protection against diarrheal illnesses.     

Abnormal apical-to-basal transport of dietary ovalbumin by secretory IgA stimulates a mucosal Th1 response

In celiac disease, enhanced permeability to gliadin peptides can result from their apico-basal transport by secretory immunoglobulin A1 (SIgA1) binding to the CD71 receptor ectopically expressed at the gut epithelial surface. Herein, we have established a mouse model in which there is apico-basal transport of the model antigen ovalbumin (OVA) by specific SIgA1 and have analyzed local T-cell activation. Transgenic DO11.10 mice were grafted with a hybridoma-secreting OVA-specific humanized IgA1, which could bind mouse CD71 and which were released in the intestinal lumen as SIgA. CD71 expression was induced at the gut apical surface by treating the mice with tyrphostin A8. Following gavage of the mice with OVA, OVA-specific CD4⁺ T cells isolated from the mesenteric lymph nodes displayed higher expression of the activation marker CD69 and produced more interferon gamma in mice bearing the hybridoma-secreting OVA-specific IgA1, than in ungrafted mice or in mice grafted with an irrelevant hybridoma. These results indicate that the protective role of SIgA1 might be jeopardized in human pathological conditions associated with ectopic expression of CD71 at the gut surface.     

Effects of Maillard reaction conditions on in vitro immunoglobulin G binding capacity of ovalbumin using response surface methodology

This study aims to investigate the effects of temperature, time, pH, ovalbumin/glucose ratio, and ovalbumin concentration on the potential allergenicity of ovalbumin during the Maillard reaction, and to define the key influential factors. Results indicated that immunoglobulin G (IgG) binding of ovalbumin could either be increased or decreased, depending on the reaction temperature, and the glycation parameters could work collectively. Response surface methodology (RSM) was used to optimize conditions under temperature below denaturation of ovalbumin. The key influential factor was temperature, followed by pH and ovalbumin concentrations. Under the optimized condition, a reduction of immunoglobulin E (IgE) binding to 61.86% was observed. RSM was proved to be a good tool in optimizing the Maillard reaction parameters to reduce potential allergenicity of ovalbumin.     

Development of gut immunoglobulin A production in piglet in response to innate and environmental factors

The current review focuses on pre- and post-natal development of intestinal immunoglobulin A (IgA) production in pig. IgA production is influenced by intrinsic genetic factors in the foetus as well as extrinsic environmental factors during the post-natal period. At birth, piglets are exposed to new antigens through maternal colostrums/milk as well as exogenous microbiota. This exposure to new antigens is critical for the proper development of the gut mucosal immune system and is characterized mainly by the establishment of IgA response. A second critical period for neonatal intestinal immune system development occurs at weaning time when the gut environment is exposed to new dietary antigens. Neonate needs to establish oral tolerance and in the absence of protective milk need to fight potential new pathogens.     

Mould extracts increase the allergic response to ovalbumin in mice

BACKGROUND: Exposure to moulds in indoor air is thought to induce asthma in susceptible persons. Moulds may contain several potent allergens. However, more importantly, moulds may increase the allergic response to other allergens (adjuvant effect). Previously, we have found that a beta-1,3-glucan from the cell wall of the fungus Sclerotinia sclerotiorum increases the allergic response to the model allergen ovalbumin (OVA) in a mouse model. OBJECTIVE: In the present study, we wanted to confirm the adjuvant effect of another beta-1,3-glucan, MacroGard (MG) from baker's yeast in this model. More importantly, we wished to explore the putative effects of extracts from the moulds Cladosporium herbarum (CH) and Penicillium chrysogenum (PC) using the very same model as used to explore effects of beta-glucans. METHODS: Groups of eight Balb/c mice were injected with OVA alone, OVA+extract or OVA+MG, into one footpad. On day 21, all mice were reinjected with OVA, before exsanguination on day 26. The levels of OVA-specific IgE, IgG1 and IgG2a in serum were measured by ELISA. RESULTS: Compared with OVA alone, OVA+MG, OVA+CH extract and OVA+PC extract increased OVA-specific IgE and IgG1 levels significantly. For all groups, the levels of IgG2a anti-OVA remained similar to those of the OVA-alone group. CONCLUSIONS: Our results show that extracts from CH and PC, and the beta-1,3/1,6-glucan from baker's yeast have adjuvant effects on the allergic response in mice.     

Lack of immunoglobulin E response to longstanding strongyloidiasis.

Patients harbouring worm infections usually have very marked elevations of serum immunoglobulin E (IgE) concentration. However, in a group of twenty ex-Far East prisoners of war with strongyloidiasis only two (10%) had raised levels due to the worm, and these were only moderately elevated. This poor IgE response may be related to the very longstanding nature of the infection (at least 30 years). The patients may have a form of immunological incompetence, or may have become immunologically tolerant to the parasite.     

Effect of dietary restriction on total and bacterium-specific mucosal secretory immunoglobulin A in bile-diverted intestinal self-filling blind loops.

The effect of starvation on the mucosal secretory immunoglobulin A (sIgA) response to bacterial antigens was studied in bile-free rat self-filling blind loops constructed at the end of a Roux-en-Y branch of jejunum. Rats were fed a 50% restricted diet for 1 to 4 weeks after surgery. sIgA was measured in the mucosa and lumen by an enzyme-linked immunosorbent assay. Dietary restriction caused a final rise of luminal sIgA which was less than 50% of that of normally fed controls Luminal bacteria counts were not different in the two groups. The percentage of total sIgA precipitated with intestinal bacteria was not significantly affected by dietary restriction, and there was no change in the specific binding of sIgA to several bacterial species. Nonprecipitated sIgA exhibited a low but significant specific binding to bacteria in both diet-restricted and fed rats. Diet restriction therefore reduced the total sIgA response to luminal bacteria, but the specific bacterial binding capacity per microgram of sIgA was not altered. In these short-term experiments diet-restricted animals appeared to be capable of secreting sIgA in excess of requirement, since the nonprecipitable luminal fraction contained free sIgA with binding capacity for bacteria. The ability of sIgA to react with specific antigens may therefore be of more significance as an indicator of bacterial susceptibility than the measurement of total sIgA.