Modulatory effect of Tagetes erecta flowers essential oils via Nrf2/HO-1/NF-κB/p65 axis mediated suppression of N-methyl-N'nitro-N-nitroguanidine (MNNG) induced gastric cancer in rats.

Protective effect of Tagetes erecta flowers essential oils was investigated on oxidative stress, immune response, inflammation, and apoptosis against N-methyl-N'nitro-N-nitroguanidine (MNNG) induced gastric cancer in rats. Essential oil were extracted from Tagetes erecta flowers and analyzed using gas chromatography-mass spectrometry (GC-MS). For observing a protective effect against MNNG induced gastric cancer, we divided rats into 4 groups (group A to D) having 10 rats in each group. Performed various experiments and measured a different parameters to investigate antioxidant activity, immune response, anti-inflammatory and anti-apoptotic activity. The levels of malondialdehyde were markedly increased in the presence of N-methyl-N'nitro-N-nitroguanidine, whereas, the antioxidant activities of superoxide dismutase, and catalase were lowered in the treated rats in contrast with the control. Intervention with TEEO to gastric cancer-induced rats upregulated the redox status and the activity of the immune system to decrease cancer risk. The proinflammatory cytokines (IL-6 and TNF-α) secretions that were induced by MNNG were markedly inhibited by TEEO. Administration of TEEO also significantly reduced terminal deoxynucleotidyl transferase dUTP nick end labeling positive gastric cancer cells, expression of mRNA of caspase-3, and Bax. Whereas, the expression of Bcl-2 was increased. Additionally, downregulation of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) and IκBα degradation and the nuclear factor-κB (NF-κB) p65 expression in tissues of the stomach of MNNG-induced-rats were markedly elevated due to TEEO. This suggested possession of TEEO with a protective shield against MNNG induced gastric cancer by the exertion of antioxidative stress, anti-apoptotic response, the anti-inflammatory response through Nrf2/HO-1, and NF-κB signaling pathways.

Influence of Nigella sativa seeds, Rosmarinus officinalis leaves and their combination on growth performance, immune response and rumen metabolism in Dorper lambs.

The objective of this study was to determine the effects of dietary supplementation of Nigella sativa L. seeds, Rosmarinus officinalis L. leaves and their combination on rumen metabolism, nutrient intake and digestibility, growth performance, immune response and blood metabolites in Dorper lambs. Twenty-four entire male Dorper lambs (18.68 ± 0.6 kg, 4-5 months old) were randomly assigned to a concentrate mixture containing on a dry matter basis either, no supplement (control, T1), 1% R. officinalis leaves (T2), 1% N. sativa seeds (T3) or 1% R. officinalis leaves +1% N. sativa seeds (T4). The lambs had ad libitum access to urea-treated rice straw (UTRS) and were raised for 90 days. Supplemented lambs had greater (P < 0.05) intake of DM and UTRS than the control lambs. The T4 lambs had lower (P < 0.05) nutrient digestibility than those fed other treatments. Total and daily weight gain was greater (P < 0.05) in T2 lambs than those fed other diets. The T3 and T4 lambs had greater (P < 0.05) ruminal pH than the T1 and T2 lambs. Supplemented lambs had lower (P < 0.05) ruminal total volatile fatty acids, acetate, propionate, NH3-N and C18:0 than the control lambs. The T4 lambs had lower (P < 0.05) population of Fibrobacter succinogenes, Ruminococcus albus, methanogens and total protozoa compared with those fed other diets. Supplemented lambs had lower (P < 0.05) neutrophils, basophils and serum urea and greater (P < 0.05) serum IgA and IgG compared with the control lambs. The current results emphasised the variation in the efficacy of medicinal plants in ruminant nutrition.

Supplemental feeding of a gut microbial metabolite of linoleic acid, 10-hydroxy-cis-12-octadecenoic acid, alleviates spontaneous atopic dermatitis and modulates intestinal microbiota in NC/nga mice.

The present study investigated the antiallergic and anti-inflammatory effects of 10-hydroxy-cis-12-octadecenoic acid (HYA), a novel gut microbial metabolite of linoleic acid, in NC/Nga mice, a model of atopic dermatitis (AD). Feeding HYA decreased the plasma immunoglobulin E level and skin infiltration of mast cells with a concomitant decrease in dermatitis score. HYA feeding decreased TNF-α and increased claudin-1, a tight junction protein, levels in the mouse skin. Cytokine expression levels in the skin and intestinal Peyer's patches cells suggested that HYA improved the Th1/Th2 balance in mice. Immunoglobulin A concentration in the feces of the HYA-fed mice was approximately four times higher than that in the control mice. Finally, denaturing gradient gel electrophoresis of the PCR-amplified 16 S rRNA gene of fecal microbes indicated the modification of microbiota by HYA. Taken together, the alterations in the intestinal microbiota might be, at least in part, associated with the antiallergic effect of HYA.

Effects of formaldehyde inhalation on humoral immunity and protective effect of Nigella sativa oil: An experimental study.

AIM: This study was carried out to determine the effects of formaldehyde (FA) inhalation on the humoral immunity of rats and the protective effect of Nigella sativa (NS) oil. MATERIALS AND METHODS: The rats (n = 33) were divided into five groups, with five animals in the control group (FA-free air) and seven in the other four groups. Group FA1 was exposed to FA (5 ppm), group FA + NS1 was treated with NS and exposed to FA (5 ppm), group FA2 was exposed to FA (10 ppm), and group FA + NS2 was treated with NS and exposed to FA (10 ppm). At the end of a 4-week study period, blood samples were collected. Enzyme-linked immunosorbent assay was used to determine the levels of serum total immunoglobulin A (IgA), total immunoglobulin M (IgM), total immunoglobulin G (IgG), and complement 3 (C3). RESULTS: FA inhalation significantly increased serum IgA, IgM, and C3 levels and decreased serum IgG levels compared with the control group. NS administration decreased serum IgA, IgM, and C3 levels, which were induced by FA inhalation. CONCLUSION: FA inhalation significantly increased acute antibody responses and C3 levels in a dose-dependent manner compared with the control group. FA inhalation decreased the secondary immune response compared with the control group. Levels of acute antibody responses and complement following exposure to FA inhalation returned to normal following treatment with NS (immunoregulatory effect). However, NS did not affect the secondary immune response.

Case Study: Nutritional and Lifestyle Support to Reduce Infection Incidence in an International-Standard Premier League Soccer Player.

Professional soccer players are exposed to large amounts of physiological and psychological stress, which can increase infection risk and threaten availability for training and competition. Accordingly, it is important for practitioners to implement strategies that support player well-being and prevent illness. This case study demonstrates how a scientifically supported and practically applicable nutrition and lifestyle strategy can reduce infection incidence in an illness-prone professional soccer player. In the 3 months before the intervention, the player had 3 upper-respiratory tract infections (URTIs) and subsequently missed 3 competitive matches and 2 weeks' training. He routinely commenced morning training sessions in the fasted state and was estimated to be in a large daily energy deficit. Throughout the 12-week intervention, the amount, composition, and timing of energy intake was altered, quercetin and vitamin D were supplemented, and the player was provided with a daily sleep and hygiene protocol. There was a positive increase in serum vitamin D 25(OH) concentration from baseline to Week 12 (53 n·mol-1 to 120 n·mol-1) and salivary immunoglobulin-A (98 mg·dl-1 to 135 mg·dl-1), as well as a decline in the number of URTI symptoms (1.8 ± 2.0 vs. 0.25 ± 0.5 for Weeks 0-4 and Weeks 8-12, respectively). More important, he maintained availability for all training and matches over the 12-week period. We offer this case study as a real-world applied example for other players and practitioners seeking to deploy nutrition and lifestyle strategies to reduce risk of illness and maximize player availability.

From goat colostrum to milk: physical, chemical, and immune evolution from partum to 90 days postpartum.

This study focused on the study of the changes originated in the milk from partum until d 90 of lactation. Ten multiparous Majorera goats, bred carefully under animal health standards, with a litter size of 2 kids (the average in this breed is 1.83 prolificacy) and similar gestation length (149 ± 1 d) were used. Goat kids were removed from their dams to avoid interferences with the study. Compositional content (fat, protein, and lactose) were measured, as well as some other properties, including pH, density, titratable acidity, ethanol stability, rennet clotting time, and somatic cell count. Moreover, immunity molecules (IgG, IgA, and IgM concentrations and chitotriosidase activity) received great attention. Fat and protein content were higher in the first days postpartum, whereas lactose content was lower. Density, titratable acidity, rennet clotting time, and somatic cell count decreased throughout the lactation period, whereas pH and ethanol stability increased. Relative to the immunological parameters, each measured parameter obtained its maximum level at d 0, showing the first milking as the choice to provide immunity to the newborn kids. On the other hand, this study might be used to establish what the best use is: processing or kid feeding.

Versatile substrates and probes for IgA1 protease activity.

Bacterial meningitis is a severe infectious disease with high mortality. Gram-positive and Gram-negative bacteria that cause meningitis secrete immunoglobulin A1 (IgA1) proteases to assist in mucosal colonization, invasion, and immune evasion. IgA1 proteases have unique selectivity, with few reported substrates other than IgA1 from human tissue. Here we describe the design, characterization, and application of peptide substrates for diverse IgA1 proteases from Neisseria, Haemophilus, and Streptococcus bacteria. IgA1 proteases from diverse strains showed unexpected selectivity profiles among peptide substrates derived from autoproteolytic sites. A fluorescence probe derived from one of these peptides was used to quantitate IgA1 protease activity in buffer and in human cerebrospinal fluid; it was able to detect recombinant Haemophilus influenzae type 1 IgA1 protease at less than 1 µg mL(-1) . We also used the probe to establish the first high-throughput screen for IgA1 protease inhibitors. This work provides tools that will help investigate the roles of IgA1 proteases in bacterial colonization, immune evasion, and infection.

Intestinal IgA⁺ cell numbers as well as IgA, IgG, and IgM contents correlate with mucosal humoral immunity of broilers during supplementation with high fluorine in the diets.

Fluoride (F), a well-recognized harmful substance, is easily absorbed by the intestinal mucosa. The intestinal mucosal immune system is equipped with unique innate and adaptive defense mechanisms that provide a first line of protection against infectious agents. Meanwhile, immunoglobulins are the major secretory products of the adaptive immune system and their levels can be a strong indicator of a disease or condition. In this study, therefore, we investigated the effects of high dietary fluorine on the numbers of immunoglobulin A-positive (IgA(+)) cells in the lamina propria of intestines (duodenum, jejunum and ileum) by immunohistochemistry as well as on the contents of immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) in the mucosa of intestines (duodenum, jejunum, and ileum) by enzyme-linked immunosorbent assay (ELISA). A total of 280 1-day-old healthy avian broilers were randomly divided into four groups and fed on a corn-soybean basal diet as control diet (fluorine 22.6 mg/kg) or the same basal diet supplemented with 400, 800, and 1,200 mg/kg fluorine (high fluorine groups I, II, and III) in the form of sodium fluoride (NaF) for 42 days. The experimental data showed that the numbers of IgA(+) cells as well as the IgA, IgG, and IgM contents were significantly decreased (P < 0.01 or P < 0.05) in the high fluorine groups II and III when compared with those of the control group. It was concluded that dietary fluorine in the range of 800-1,200 mg/kg significantly reduced the numbers of the IgA(+) cells and the contents of aforementioned immunoglobulins in the intestines (duodenum, jejunum, and ileum) of broilers, which could finally impact the mucosal humoral immune function in the intestines by a way that reduces the lymphocyte population and/or lymphocyte activation.

Salmon consumption during pregnancy alters fatty acid composition and secretory IgA concentration in human breast milk.

Fish oil supplementation during pregnancy alters breast milk composition, but there is little information about the impact of oily fish consumption. We determined whether increased salmon consumption during pregnancy alters breast milk fatty acid composition and immune factors. Women (n = 123) who rarely ate oily fish were randomly assigned to consume their habitual diet or to consume 2 portions of farmed salmon per week from 20 wk of pregnancy until delivery. The salmon provided 3.45 g long-chain (LC) (n-3) PUFA/wk. Breast milk fatty acid composition and immune factors [soluble CD14, transforming growth factor-ß (TGFß)1, TGFß2, and secretory IgA] were analyzed at 1, 5, 14, and 28 d postpartum (PP). Breast milk from the salmon group had higher proportions of EPA (80%), docosapentaenoic acid (30%), and DHA (90%) on d 5 PP compared with controls (P < 0.01). The LC (n-6) PUFA:LC (n-3) PUFA ratio was lower for the salmon group on all days of PP sampling (P ≤ 0.004), although individual (n-6) PUFA proportions, including arachidonic acid, did not differ. All breast milk immune factors decreased between d 1 and 28 PP (P < 0.001). Breast milk secretory IgA (sIgA) was lower in the salmon group (d 1-28 PP; P = 0.006). Salmon consumption during pregnancy, at the current recommended intakes, increases the LC (n-3) PUFA concentration of breast milk in early lactation, thus improving the supply of these important fatty acids to the breast-fed neonate. The consequence of the lower breast milk concentration of sIgA in the salmon group is not clear.

Identification of periparturient mare and foal associated predictors of post parturient immunoglobulin A concentrations in Thoroughbred foals.

REASONS FOR PERFORMING THE STUDY: Prior to the start of endogenous production of immunoglobulins (Igs), absorption of maternal Igs is important to protect against pathogens in the early neonatal period. It is possible that mare- or foal-associated factors may influence neonatal IgA concentrations. OBJECTIVES: The temporal relationships among serum and milk IgA concentrations in Thoroughbred mare-foal pairs were explored to determine if periparturient mare- and foal-associated factors contribute to the prediction of foal serum IgA concentrations. METHODS: Blood and milk samples as well as complete veterinary records, were collected for 84 Thoroughbred mare-foal pairs from one month before to 2 months after parturition. Samples were tested using enzyme-linked immunosorbent assay (ELISA) for concentrations of IgA. Pairwise correlation coefficients were estimated (P < 0.01) and simple linear regression used to investigate unconditional associations between mare IgA levels, mare and foal risk factors and foal serum IgA concentration at 12 h. Backwards, stepwise elimination of nonsignificant factors was used to create a final model. RESULTS: There were significant temporal relationships among mare serum IgA and among colostrum and milk IgA concentrations within mares (P < 0.01). Mare serum IgA concentrations up to one month before parturition were associated with foal serum IgA concentrations at all time points and with colostrum and milk IgA concentrations. Mare serum IgA at -28 days and parity were associated with foal serum IgA concentration at 12 h (P < 0.001). CONCLUSIONS: Mare serum IgA concentrations up to 28 days before parturition, together with mare parity, are indicative of neonatal foal serum IgA concentrations. POTENTIAL RELEVANCE: Mare serum and colostrum IgA concentrations may be useful peripartum predictors of neonatal mucosal immune status, enabling earlier intervention to prevent the consequences of mucosal infections.

Oral-nasopharyngeal dendritic cells mediate T cell-independent IgA class switching on B-1 B cells.

Native cholera toxin (nCT) as a nasal adjuvant was shown to elicit increased levels of T-independent S-IgA antibody (Ab) responses through IL-5- IL-5 receptor interactions between CD4+ T cells and IgA+ B-1 B cells in murine submandibular glands (SMGs) and nasal passages (NPs). Here, we further investigate whether oral-nasopharyngeal dendritic cells (DCs) play a central role in the induction of B-1 B cell IgA class switch recombination (CSR) for the enhancement of T cell-independent (TI) mucosal S-IgA Ab responses. High expression levels of activation-induced cytidine deaminase, Iα-Cµ circulation transcripts and Iµ-Cα transcripts were seen on B-1 B cells purified from SMGs and NPs of both TCRß⁻/⁻ mice and wild-type mice given nasal trinitrophenyl (TNP)-LPS plus nCT, than in the same tissues of mice given nCT or TNP-LPS alone. Further, DCs from SMGs, NPs and NALT of mice given nasal TNP-LPS plus nCT expressed significantly higher levels of a proliferation-inducing ligand (APRIL) than those in mice given TNP-LPS or nCT alone, whereas the B-1 B cells in SMGs and NPs showed elevated levels of transmembrane activator and calcium modulator cyclophilin ligand interactor (TACI) expression. Interestingly, high frequencies of IgA+ B-1 B cells were induced when peritoneal IgA⁻ IgM+ B cells were stimulated with mucosal DCs from mice given nasal TNP-LPS plus nCT. Taken together, these findings show that nasal nCT plays a key role in the enhancement of mucosal DC-mediated TI IgA CSR by B-1 B cells through their interactions with APRIL and TACI.

Oral immunogenicity of the plant proteinase bromelain.

Bromelain is a natural mixture of proteolytic enzymes derived from pineapple stem that has been shown to have anti-inflammatory activity when administered orally. Although most proteins given orally without adjuvant (e.g., food) result in tolerance, we previously reported that long-term oral exposure to bromelain stimulated the development of high serum anti-bromelain antibody titers. The purpose of these studies was to further investigate the mechanisms responsible for the immunogenicity of oral bromelain. Results showed that repeated exposure was required for development of anti-bromelain antibodies, with strong antibody responses in all mice that received at least 12 doses of bromelain either orally or intragastrically over 3-6 weeks. Proteolytic activity was required for strong oral immunogenicity in the absence of conventional adjuvant, with strong serum antibody responses generated against proteolytically active bromelain and trypsin, but not against ovalbumin, lysozyme, or inactivated bromelain. Significantly higher anti-bromelain antibody titers were seen in IL-10-deficient versus wild-type mice, suggesting that simultaneous treatments that decrease IL-10 activity may further enhance systemic antibody responses following oral exposure. The antibodies generated did not affect the proteolytic activity of bromelain. The data demonstrate that proteolytically active antigens such as bromelain can stimulate both systemic and mucosal immune responses following repeated oral exposure. Further studies of the mechanisms involved in generation of immune responses following oral exposure to proteolytically active antigens can lead to a better understanding of mechanisms of oral tolerance and to the development of novel adjuvants for oral vaccines.

Potential prophylactic value of bovine colostrum in necrotizing enterocolitis in neonates: an in vitro study on bacterial attachment, antibody levels and cytokine production.

Necrotizing enterocolitis (NEC) is an important disease of low birth-weight neonates. The immaturity of the gut mucosa may result in close contact between the host epithelium and microorganisms which are normally confined to the gut lumen. Damage of the mucosa due to endotoxin, cytokine production or other factors is believed to then occur. The aim of this study was to determine whether spray-dried bovine colostrum demonstrated potential in vitro as a prophylactic for NEC. Antiadherence was measured using a tissue culture assay and antibody levels against Enterobacteriaceae were determined by ELISA. The effect of bovine colostrum on the production of cytokines implicated in NEC was determined by a multiplex bead assay. Enterobacter cloacae, Klebsiella oxytoca, Escherichia coli, Serratia marcescens and Klebsiella pneumoniae ssp. pneumoniae were common in both NEC positive and NEC negative infants and IgA and IgG1 antibodies to these species were present in the bovine colostrum. Pretreatment with bovine colostrum produced a significant decrease (P<0.001) in attachment of bacteria to HT-29 cells. Bovine colostrum significantly increased the production of IL-8 in HT-29 cells and IL-8, IL-6 and TNF-alpha in THP-1 cells (P<0.001). The potential of bovine colostrum to increase the production of inflammatory mediators could limit its usefulness.

Determination of aberrant O-glycosylation in the IgA1 hinge region by electron capture dissociation fourier transform-ion cyclotron resonance mass spectrometry.

In a number of human diseases of chronic inflammatory or autoimmune character, immunoglobulin molecules display aberrant glycosylation patterns of N- or O-linked glycans. In IgA nephropathy, IgA1 molecules with incompletely galactosylated O-linked glycans in the hinge region (HR) are present in mesangial immunodeposits and in circulating immune complexes. It is not known whether the Gal deficiency in IgA1 proteins occurs randomly or preferentially at specific sites. To develop experimental approaches to address this question, the synthetic IgA1 hinge region and hinge region from a naturally Gal-deficient IgA1 myeloma protein have been analyzed by 9.4 tesla Fourier transform-ion cyclotron resonance mass spectrometry. Fourier transform-ion cyclotron resonance mass spectrometry offers two complementary fragmentation techniques for analysis of protein glycosylation by tandem mass spectrometry. Infrared multiphoton dissociation of isolated myeloma IgA1 hinge region peptides confirms the amino acid sequence of the de-glycosylated peptide and positively identifies a series of fragments differing in O-glycosylation. To localize sites of O-glycan attachment, synthetic IgA1 HR glycopeptides and HR from a naturally Gal-deficient polymeric IgA1 myeloma protein were analyzed by electron capture dissociation and activated ion-electron capture dissociation. Multiple sites of O-glycan attachment (including sites of Gal deficiency) in myeloma IgA1 HR glycoforms were identified (in all but one case uniquely). These results represent the first direct identification of multiple sites of O-glycan attachment in IgA1 hinge region by mass spectrometry, thereby enabling future characterization at the molecular level of aberrant glycosylation of IgA1 in diseases such as IgA nephropathy.

Fc receptor gamma chain residues at the interface of the cytoplasmic and transmembrane domains affect association with FcalphaRI, surface expression, and function.

The assembly of multiple subunit immunoreceptors is dependent on transmembrane interactions. The Fc receptor gamma (FcR-gamma) chain is a ubiquitous immune receptor tyrosine-based activation motif-containing dimeric subunit, gamma(2), which in humans associates with both the activating members of the leukocyte receptor cluster, including the IgA receptor FcalphaRI, and the classical Fc receptors, including the IgE receptor FcepsilonRI. This study identifies a new site in the transmembrane region of FcR-gamma that affects receptor assembly and surface expression with FcalphaRI but not with FcepsilonRI. The wild type complex, FcalphaRI-gamma(2)WT, remains robustly associated in both Brij-96 and Thesit detergent conditions. However, mutation of either Tyr(25) or Cys(26) of FcR-gamma, near the interface of the transmembrane and cytoplasmic regions, resulted in impaired FcR-gamma association with FcalphaRI. This association was disrupted in the presence of the detergent Brij-96 but was preserved in milder conditions using the detergent Thesit. Ligand-mediated cross-linking of the FcalphaRI-gamma(2)Y25F mutant receptor resulted in diminished signal transduction, including an abnormal calcium response, compared with the FcalphaRI-gamma(2)WT receptor. Furthermore, the FcalphaRI-gamma(2)Y25F mutant receptor was expressed at the cell surface at approximately 10% of that of the wild type, whereas the surface expression of FcepsilonRI-gamma(2)Y25F was not significantly different from the wild type. In contrast, although the FcalphaRI-gamma(2)C26S mutant was also less stably associated, it was not reduced in surface expression or function. Thus, these TM residues of FcR-gamma are important for association with FcalphaRI and probably other activating LRC members but not with the classical FcR, FcepsilonRI.

Novel antimalarial antibodies highlight the importance of the antibody Fc region in mediating protection.

Parasite drug resistance and difficulties in developing effective vaccines have precipitated the search for alternative therapies for malaria. The success of passive immunization suggests that immunoglobulin (Ig)-based therapies are effective. To further explore the mechanism(s) by which antibody mediates its protective effect, we generated human chimeric IgG1 and IgA1 and a single-chain diabody specific for the C-terminal 19-kDa region of Plasmodium yoelii merozoite surface protein 1 (MSP119), a major target of protective immune responses. These novel human reagents triggered in vitro phagocytosis of merozoites but, unlike their parental mouse IgG2b, failed to protect against parasite challenge in vivo. Therefore, the Fc region appears critical for mediating protection in vivo, at least for this MSP119 epitope. Such antibodies may serve as prototype therapeutic agents, and as useful tools in the development of in vitro neutralization assays with Plasmodium parasites.

Simplified method for purification of colostrum to obtain secretory component of immunoglobulin A, using secretory component as a reference protein in tracheal aspirate fluid.

Many studies employ bronchoalveolar lavage fluid for assessment of biologically active substances secreted from the lung. However, investigators continue to search for a useful reference standard to correct for the inevitable but variable degree of dilution of this fluid. The glycoprotein, soluble secretory component of IgA, may serve as a valid reference protein. We report a simplified method for the purification of secretory component from colostrum. Soluble secretory component was isolated from human colostrum using serial centrifugation, size-exclusion fractionation and ion-exchange chromatography. Secretory component rich fractions were assayed by enzyme immunoassay. They were also evaluated for total amino acid content and distribution and sequence determination with satisfactory agreement with published results. We then demonstrated that soluble secretory component concentration in tracheal aspirate fluid did not correlate with either albumin or with total protein measured in the same samples. Therefore, we conclude that the secretory component of IgA serves as a useful reference marker because its use may avoid errors resulting from leakage of plasma proteins into epithelial lining fluid. Advantages of this method for establishing a standard for secretory component include ready availability of soluble secretory component, simplicity of the method and relative rapidity of the techniques.

Human colostrum IgA antibodies reacting to enteropathogenic Escherichia coli antigens and their persistence in the faeces of a breastfed infant.

IgA antibodies reacting to enteropathogenic Escherichia coli (EPEC) antigens in human colostrum and their role in the inhibition of EPEC adherence to HEp-2 cells were studied. Colostrum IgA was isolated with a Sepharose anti-IgA column. IgA-depleted colostrum lost its inhibitory effect on EPEC adhesion, while the IgA-enriched eluate was a potent adherence inhibitor. The same eluate showed a significant loss of inhibitory activity after absorption with an EPEC strain showing localised adherence (LA+), but no alteration after absorption with an LA- strain. No bands were observed in Western blot analysis with LA+ absorbed eluate and with a crude extract of the EPEC strain, but the eluate absorbed with LA- showed a strong recognition of a 94-kDa band, a molecular weight equivalent to that of intimin. Colostrum antibodies reacting to non-protein antigens were not detected by Western blot analysis. The persistence of anti-EPEC IgA in the gastrointestinal tract was shown by the strong reactivity to the 94-kDa band in Western blot analysis of one mother's colostrum and her infant's faeces. These data confirm the role of colostrum antibodies in protecting the neonate against infections due to EPEC.

Impact of large-dose vitamin A supplementation on childhood diarrhoea, respiratory disease and growth.

One hundred and seventy-two 0.5-3.0-year-old children in a mountainous area of northern Hebei Province of China were randomly assigned to a vitamin A supplementation group (n = 98) or a control group (n = 74) for a 1 year double-blind study. Capsules containing 200,000 IU vitamin A and 40 IU vitamin E were given to the children in the experimental group 3 and 9 months after baseline examination. During the 12 month study period, there was a significant reduction in the incidence of diarrhoea (P < 0.01) and respiratory disease (P < 0.01) in the children of the experimental group compared to the control. Risk of diarrhoea and respiratory disease were respectively 2.5 and 3.4 times higher in the control children. Serum retinol and IgA levels of the treatment group were significantly higher than that of control group (P < 0.01) 7 weeks after first supplementation. There was no significant difference in saliva IgA level between groups. No significant differences in growth were observed. It was concluded that supplementation with large doses of vitamin A decreased the incidence and severity of diarrhoea and respiratory disease in these children, possibly through enhanced activity of the immune system, but had no effect on growth over 1 year.

A lactogenic-immune-deficiency-syndrome in cows: unexplained phenomenon.

The majority of adult cows in a certain dairy herd, were found to have very low levels of immunoglobulins (Igs) in their colostrum. This phenomenon was defined by us as Lactogenic-Immune-Deficiency-Syndrome (LIDS). The mean IgG levels were 44.5 and 57.2 mg ml-1 respectively (on two different occasions) as compared to that of a control group which was 103.4 mg ml-1. The levels of Igs in the colostra of heifers from the same herd were found to be higher than those of adult cows. The degree of LIDS was found to be closely related to the age of cows in the herd. The low levels of Igs in the colostra were not directly linked to their concentrations in the sera of the affected cows. The relatively low amount of IgA in the affected colostra suggests that the local production in the lymph tissue associated with the mammary glands is impaired as well. In order to investigate the etiology of the phenomenon, tests were carried out to reveal whether bovine leucosis virus (BLV) infection or immune complexes were involved in the pathogenesis of LIDS. The results were negative. The etiology of LIDS remains for the time being unknown.