Reducing Campylobacter jejuni colonization in broiler chickens by in-feed supplementation with hyperimmune egg yolk antibodies.

Campylobacter infections sourced mainly to poultry products, are the most important bacterial foodborne zoonoses worldwide. No effective measures to control these infections in broiler production exist to date. Here, we used passive immunization with hyperimmune egg yolks to confer broad protection of broilers against Campylobacter infection. Two novel vaccines, a bacterin of thirteen Campylobacter jejuni (C. jejuni) and C. coli strains and a subunit vaccine of six immunodominant Campylobacter antigens, were used for the immunization of layers, resulting in high and prolonged levels of specific immunoglobulin Y (IgY) in the hens' yolks. In the first in vivo trial, yolks (sham, bacterin or subunit vaccine derived) were administered prophylactically in the broiler feed. Both the bacterin- and subunit vaccine-induced IgY significantly reduced the number of Campylobacter-colonized broilers. In the second in vivo trial, the yolks were administered therapeutically during three days before euthanasia. The bacterin IgY resulted in a significant decrease in C. jejuni counts per infected bird. The hyperimmune yolks showed strong reactivity to a broad representation of C. jejuni and C. coli clonal complexes. These results indicate that passive immunization with hyperimmune yolks, especially bacterin derived, offers possibilities to control Campylobacter colonization in poultry.

In vitro efficacy of potentiated egg yolk powder against Campylobacter jejuni does not correlate with in vitro efficacy.

Campylobacter jejuni is a zoonotic agent responsible for the foodborne gastroenteritis campylobacteriosis. Control of C. jejuni load in the poultry primary production is recognized as an avenue to reduce human exposure to the pathogen. As for now, no commercially applicable control methods exist at the farm. Several studies tested egg yolk powders, potentiated or not against C. jejuni, as feed additives for chicken and suggested that the quantity and quality of the antibodies presence in the yolk are determinant factors for the full success of this approach. Unfortunately, data from these studies inconsistently showed a reduction of cecal C. jejuni carriage. Our first goal wwas to characterize (quantification by ELISA, agglutination test, bacterial antigen recognition profiles by Western blot, bactericidal effect by serum killing assays and C. jejuni mobility by soft agar migation) the antibodies extracted from egg yolk powders originating from different egg production protocols. Secondly, these powders were microencapsulated and recharacterized. Finally the protected powders were tested as a feed additive to destabilize C. jejuni colonization in an in vivo assay. Despite the in vitro results indicating the ability of the egg yolk powders to recognize Campylobacter and potentially alter its colonization of the chicken caecum, these results were not confirmed in the in vivo trial despite that specific caecal IgY directed toward Campylobacter were detected in the groups receiving the protected powders. More research is needed on Campylobacter in order to effectively control this pathogen at the farm.

Physicochemical properties of anti Vibrio harveyi egg yolk antibody (IgY) and its immunological influence in Indian white shrimp Fenneropenaeus indicus.

Edible antibodies specific to host pathogens is an attractive approach to establish protective immunity, especially against gastrointestinal pathogens both in humans and animals. The edible antibody of anti-Vibrio harveyi IgY (anti-V. h IgY) was produced by antigen mixed with immunoadjuvant Asparagus racemosus and Glycine max. Hens were immunized and eggs were collected five weeks after the immunization. Anti-V. harveyi IgY stability in different digestive enzymes such as trypsin and chymotrypsin were evaluated to determine its ability to withstand in the gastrointestinal tract of F. indicus. Specific binding activity and concentration (average 9.5% of total IgY content) of the anti-V. h IgY were determined by the ELISA using V. harveyi antigen. Further the anti-V. h IgY diets including V.h wo, V.h A, V.h G and control diets were fed to F. indicus for 60 days. After 30 and 60 of feeding, group of shrimps were challenged with virulent V. harveyi. After the respective days of feeding, haematological and immunological changes were studied. The parameters including total haemocyte count (THC), coagulase activity, oxyhaemocyanin level, prophenoloxidase, intracellular superoxide anion production, lysozyme, phagocytosis and bacterial agglutinin had significantly (P ≤ .001) increased in the experimental groups in comparission with the control diet fed shrimps. The anti-V. h IgY coated diets helped to reduce the Vibrio load and boosted the immune system in F. indicus's against V. harveyi challenge. The research work shows the potential applications of egg yolk antibodies as anti-bacterial prophylactic uses for infectious diseases and suggests an edible antibody concept as an alternative to conventional antibiotics.

Pro-Cognitive Properties of the Immunomodulatory Polypeptide Complex, Yolkin, from Chicken Egg Yolk and Colostrum-Derived Substances: Analyses Based on Animal Model of Age-Related Cognitive Deficits.

The study aimed to assess the effect of the polypeptide Y complex (Yolkin), isolated from chicken egg yolk, on behavioural and cognitive functions. It also aimed to compare this activity with colostrum-derived substances (Colostrinin, Coloco), which have a confirmed impact on learning and memory. In the study, the effect of Yolkin, administered to rats of different ages, who performed various tasks involving spatial and episodic memory, motor functions and exploratory behavior, was assessed. The experiment was carried out in rats which were 6 and 12 months old. Two different doses of the studied specimens based on previous comparative studies and two different routes of administration (oral and retroperitoneal) were used. A series of behavioural tests were carried out, including an open field test, a novel object recognition test and a Morris water maze. They were used to evaluate the impact of the studied specimen on improving locomotor function and exploratory behaviour, preventing their decline and assess the functioning of episodic and spatial memory in aging rats. The administration of Yolkin gave distinct effects compared to colostrum-derived substances, although confirmed its suggested pro-cognitive action. Therefore, it may be used to enhance cognitive functions and inhibit the progression of dementia in the course of neurodegenerative disorders.

IgY antibodies in human nutrition for disease prevention.

Oral administration of preformed specific antibodies is an attractive approach against infections of the digestive system in humans and animals in times of increasing antibiotic resistances. Previous studies showed a positive effect of egg yolk IgY antibodies on bacterial intoxications in animals and humans. Immunization of chickens with specific antigens offers the possibility to create various forms of antibodies. Research shows that orally applied IgY's isolated from egg yolks can passively cure or prevent diseases of the digestive system. The use of these alternative therapeutic drugs provides further advantages: (1) The production of IgY's is a non-invasive alternative to current methods; (2) The keeping of chickens is inexpensive; (3) The animals are easy to handle; (4) It avoids repetitive bleeding of laboratory animals; (5) It is also very cost effective regarding the high IgY concentration within the egg yolk. Novel targets of these antigen specific antibodies are Helicobacter pylori and also molecules involved in signaling pathways in gastric cancer. Furthermore, also dental caries causing bacteria like Streptococcus mutans or opportunistic Pseudomonas aeruginosa in cystic fibrosis patients are possible targets. Therefore, IgY's included in food for human consumption may be able to prevent or cure human diseases.

Effect of dietary vitamin A on reproductive performance and immune response of broiler breeders.

The effects of dietary vitamin A supplementation on reproductive performance, liver function, fat-soluble vitamin retention, and immune response were studied in laying broiler breeders. In the first phase of the experiment, 1,120 Ross-308 broiler breeder hens were fed a diet of corn and soybean meal supplemented with 5,000 to 35,000 IU/kg vitamin A (retinyl acetate) for 20 weeks. In the second phase, 384 Ross-308 broiler breeder hens were fed the same diet supplemented with 5,000 to 135,000 IU/kg vitamin A (retinyl acetate) for 24 weeks. The hens' reproductive performance, the concentrations of vitamins A and E in liver and egg yolk, liver function, mRNA expression of vitamin D receptor in duodenal mucosa, antibody titers against Newcastle disease virus vaccine, and T-cell proliferation responses were evaluated. Supplementation of vitamin A at levels up to and including 35,000 IU/kg did not affect reproductive performance and quadratically affected antibody titer to Newcastle disease virus vaccine (p<0.05). Dietary addition of vitamin A linearly increased vitamin A concentration in liver and yolk and linearly decreased α-, γ-, and total tocopherol concentration in yolk (p<0.01) and α-tocopherol in liver (p<0.05). Supplementation of vitamin A at doses of 45,000 IU/kg and above significantly decreased egg weight, yolk color, eggshell thickness and strength, and reproductive performance. Dietary vitamin A significantly increased mRNA expression of vitamin D receptor in duodenal mucosa (p<0.05), increased aspartate amino transferase activity, and decreased total bilirubin concentration in serum. Supplementation of vitamin A at 135,000 IU/kg decreased the proliferation of peripheral blood lymphocytes (p<0.05). Therefore, the maximum tolerable dose of vitamin A for broiler breeders appears to be 35,000 IU/kg, as excessive supplementation has been shown to impair liver function, reproductive performance, and immune response.

The in vitro and in vivo efficacy of hen IgY against Vibrio parahaemolyticus and Vibrio vulnificus.

The inhibitory effect of IgY against Vibrio parahaemolyticus and Vibrio vulnificus responsible for seafood-borne diseases was investigated in this study. Water-soluble fractions (WSF) of protein containing IgYs were isolated from the egg yolk of hens initially immunized with formalin inactivated V. parahaemolyticus or V. vulnificus. Protein, total and specific IgY contents of the WSF were determined. The inhibitory and protective effects of IgYs on the growth of V. parahaemolyticus and V. vulnificus were assayed in liquid medium and in mice. IgYs showed high affinity to their corresponding antigens with high titer from day 28 onwards. Protein contents and total IgY concentrations remained stable throughout the immunization period, whereas specific IgY concentrations increased steadily and reached a plateau at day 49. Specific IgY powder (150 mg/ml) significantly inhibited further multiplication of both V. parahaemolyticus and V. vulnificus in liquid medium as compared with the control IgY. The bacteria count in mice feces was lower in mice pretreated with specific IgYs than in those pretreated with PBS or control IgY. Higher survival of mice was observed in the experimental groups pretreated with either anti-V. parahaemolyticus (75% survival) or anti-V. vulnificus (87% survival) IgYs, compared with those in the control groups pretreated with PBS or nonspecific IgY. All mice in the control groups died within three days after bacteria inoculation; hence, the protective effect of specific IgYs against infection caused by V. parahaemolyticus and V. vulnificus was demonstrated.

Stability of orally administered immunoglobulin in the gastrointestinal tract.

Oral administration of immunoglobulin in the colostrum or egg yolk has been considered an effective tool for preventing enterobacterial infection via passive immunization. During this process, the transmission and residence of the active immunoglobulin are the most important conditions for successful protection. We investigated the stability of encapsulated colostrum and egg yolk immunoglobulin for the effective transmission of immunoglobulin in the gastrointestinal (GI) tract. First, we measured GI transit time. Contrast media passed through and reached the stomach within 10 min, the small intestine within 3.5 h, and the cecum within 5 h. Both the encapsulated colostrum containing anti-hepatitis A virus (HAV) antibody (IgG) and egg yolk with anti-rotavirus antibody (IgY) showed lower antibody activity than the non-encapsulated colostrum did in the stomach after administration; however, significantly higher antibody activities were observed in the encapsulated groups than in the non-encapsulated groups in the small intestine 3.5 h after the administration. In the large intestine, the antibody activities of the encapsulated groups were maintained or slightly increased in a time-dependent manner; however, the titers of each non-capsulated control were as low as the negative controls. Therefore, this encapsulation is considered a useful tool for the delivery of active antibody through the GI tract.

A novel, cost-effective and efficient chicken egg IgY purification procedure.

Chicken IgY antibodies have been touted to be a superior alternative to mammalian antibodies for use in various immunological, molecular biology and proteomics applications for several reasons. These include, but are not limited to, improved specificity due to maximum phylogenetic distance between host and recipient, cost effectiveness in maintaining commercial numbers of hens, IgY yield and the use of non-invasive methods used to isolate IgY from eggs as opposed to blood. Despite this, the routine use of IgY-based methodologies in the laboratory is not widespread. One reason for this reluctance may be derived from the difficulties and expense of isolating IgY antibodies from egg yolk in sufficient yield, with high purity at a realistic reasonable price. Here, we describe an extremely cost-effective ($5USD per egg), rapid (within 5 h), efficient and optimised technique to isolate high yields (60 mg) of high purity (~80%) chicken IgY from egg yolks using the common plant gums pectin and κ-carrageenan in the presence of calcium chloride to delipidate egg yolk mixtures whilst maintaining IgY in solution and then ammonium sulphate to subsequently precipitate the resulting IgY antibodies to higher purity. Our data demonstrates that this technique results in a high yield and purity of IgY that is comparable (if not superior to) existing commercial IgY isolation kits. The method also allows the isolation of immunologically active IgY which can be used for further downstream immunotechnological processes. Furthermore, it can also be easily implemented in a standard well equipped laboratory, and may be scaled up to commercial quantities (i.e., thousands of eggs).

Protective effect of hyperimmune egg yolk IgY antibodies against Eimeria tenella and Eimeria maxima infections.

Avian coccidiosis is caused by several distinct species of Eimeria protozoa and is the major parasitic disease of poultry of economic importance. As an alternative strategy to control avian coccidiosis without using prophylactic medications, we have investigated the efficacy of inducing passive immunity against coccidiosis by orally feeding hyperimmune IgY antibodies. In this study, a commercially available egg yolk powder, Supracox (SC), a purified IgY fraction of egg yolk prepared from hens hyperimmunized with three major species of Eimeria oocysts, were continuously fed to young chicks from hatch. Upon orally infecting these broiler chicks with Eimeria tenella and Eimeria maxima oocysts at 1 week of age, they showed significantly higher body weight gains (P<0.05) compared to the untreated controls. Furthermore, SC-fed chicks showed significantly less intestinal lesions and reduced fecal oocyst output compared to the untreated controls following oral infections with E. tenella and E. maxima. These results provide clear evidence that passive immunization of chicks with hyperimmune egg yolk IgY antibodies provide significant protection against E. tenella or E. maxima infections.

More than 10 years' continuous oral treatment with specific immunoglobulin Y for the prevention of Pseudomonas aeruginosa infections: a case report.

Immunotherapy with specific antibodies is an alternative to antibiotics for the prevention of infections in humans and animals. We have used orally administered immunoglobulin Y (IgY) preparations, purified from eggs of hens immunized with Pseudomonas aeruginosa bacteria, to prevent pulmonary P. aeruginosa infections in a group of patients with cystic fibrosis (CF). Respiratory infections are major problems for CF patients because of the thick mucus in the airways, and chronic P. aeruginosa lung infections occur in virtually all CF patients and cause morbidity and mortality. The IgY-treated group had only 2.5 P. aeruginosa-positive sputum cultures per 100 months, and none of the IgY-treated patients became chronically colonized with P. aeruginosa. In the control group, 13.7 of the cultures per 100 months were positive for P. aeruginosa, and 24% of patients became chronically colonized with P. aeruginosa. The first enrolled patient in this study has now been treated continuously for more than 10 years. During the first 8 years she only had four P. aeruginosa-positive cultures. After 8 years she became chronically infected, but still after 10 years the bacteria have not turned mucoid. No negative side effects of IgY treatment have been noted during these 10 years. To our knowledge this is the longest treatment with specific yolk antibodies for therapeutic purposes.

Effect of beta-carotene supplementation on plasma and yolk IgY levels induced by NDV vaccination in Japanese quail.

Newly hatched Japanese quail (Coturnix coturnix japonica) chicks were fed diets containing different levels of retinoids (vitamin A) or beta-carotene. Group A received a commercial diet containing 10,000 IU vitamin A per kilogram. The diets of Groups B, C, and D contained no vitamin A but were supplemented with 1-, 2.5-, and 5-fold retinol equivalents of beta-carotene. Each group contained 16 quails in a 1:1 sex ratio. At 8 weeks of age the quails were immunized orally with Newcastle disease virus (NDV) vaccine according to the manufacturer's recommendations. Boosters were given three times at two-week intervals. Blood samples were taken at two-week intervals until 14 weeks of age. The anti-NDV IgY titre was determined by a locally developed direct enzyme-linked immunosorbent assay (ELISA). Groups A and B showed nearly the same antibody response. This indicates that the preformed vitamin A and the equivalent beta-carotene have the same immunomodulatory effect. Groups receiving higher doses of beta-carotene (Groups C and D) exhibited significantly higher plasma IgY levels compared to Groups A and B. The results indicate that elevated doses of beta-carotene have a slight effect on the adaptive immune response in Japanese quail.

Response of early-weaned pigs to an enterotoxigenic Escherichia coli (K88) challenge when fed diets containing spray-dried porcine plasma or pea protein isolate plus egg yolk antibody, zinc oxide, fumaric acid, or antibiotic.

The effect of feeding diets containing either spray-dried porcine plasma (SDPP) or pea protein-isolate (PPI) supplemented with either egg yolk antibodies (EYA) from hens immunized with enterotoxigenic Escherichia coli (ETEC) (K88 and F18) antigens, ZnO, fumaric acid (FA), or carbadox (AB) on pig performance, incidence of scours, and gut morphology was studied in a 14-d experiment. Ninety 10-d-old weaned pigs were assigned to six dietary treatments in a completely randomized design to give five pens per treatment with three pigs per pen. The diets were SDPP without EYA (SDPP - EYA), PPI without EYA (PPI - EYA), PPI with EYA (PPI + EYA), PPI with ZnO (PPI + ZnO), PPI with FA (PPI + FA), or PPI with AB (PPI + AB). Diets were formulated to similar nutrient levels, with AB, EYA, FA, and ZnO at 0.25, 0.5, 2.0, and 0.4% of the diet, respectively. Pigs were weighed and bled on d 0, 7, and 14 to determine plasma urea N (PUN). Pigs were orally challenged with a 6-mL dose of 10(10) cfu/mL ETEC (K88) on d 7. On d 14, three pigs per treatment were killed to obtain sections of the small intestine for histological measurements. Weekly feed intake, BW changes, and gain:feed were determined. Incidence of scours and scour scores were monitored and fecal swabs were taken before and after ETEC challenge for PCR test to detect ETEC (K88). Feeding SDPP or supplementing PPI-based diets with EYA, ZnO, FA, or AB did not affect (P > 0.05) ADG, ADFI (as-fed basis), or gain:feed throughout the study. However, pigs fed PPI - EYA tended to have lower (P = 0.08) ADFI during wk 2 (137.9 g/d) and lower (P < 0.10) ADG from d 0 to 14 (100.1 g/d) than those fed the SDPP - EYA (156.6 g/d), PPI + EYA (151.2 g/d), PPI + ZnO (158.9 g/ d), PPI + FA (155.4 g/d), and PPI + AB (152.6 g/d) diets. Although scours was evident in all pigs 8 h after the ETEC challenge, it lasted only 3 to 5 d in pigs fed SDPP or PPI supplemented with EYA, ZnO, FA, or AB. Pigs fed PPI - EYA continued to have severe diarrhea, resulting in 40% mortality vs. 13% or less in the other groups. The PCR results showed that 81% of PPI-fed pigs continued to shed ETEC K88 7 d after ETEC challenge. Pigs fed PPI-EYA had shorter villi (P < 0.05), reduced villi:crypt ratio (P < 0.003), and higher intestinal pH (P < 0.001) and PUN (P < 0.001) than those fed SDPP or PPI supplemented with EYA, ZnO, FA, and AB. In conclusion, SDPP, EYA, ZnO, FA, and AB may have provided passive control to ETEC (K88) infection and potentially enabled young pigs to efficiently utilize a PPI-based diet.

Studies on the effect of specific egg antibodies against Escherichia coli infections in piglets.

The effect of chicken egg powder enriched with immunoglobulins specific for rotavirus antigen and fimbrial adhesions F4, F5, F6 of enterotoxigenic Escherichia coli (ETEC) (Globigen 66 S, Lohmann Animal Health, Cuxhaven, Germany) was studied in 465 sucking piglets on a commercial farm. Half of those piglets were given Globigen 66 S as an additive to milk replacer from day 2 until day 12 of life in addition to sows' milk. These piglets showed a higher intake of milk replacer and a lower prevalence of diarrhoea on days 2 and 3 of life. Statistical evaluation showed, that the effect of sows' milk on the duration of diarrhoea and on piglet weight gains was more pronounced than the effect of Globigen 66 S. Anti-ETEC F4-antibody-activities were measured using an indirect ELISA (enzyme-linked immunosorbent assay). There was an inverse relationship between the intensity of diarrhoea and colostral antibody-activity (r = -0.2). Comparison of binding affinities of avian and porcine antibodies for F4 showed only a limited common spectrum of epitopes, so, in all probability, they might complement each other in the intestine.

Chicken egg yolk antibodies as therapeutics in enteric infectious disease: a review.

Passive immunization by oral administration of specific antibodies has been an attractive approach against gastrointestinal (GI) pathogens in both humans and animals. Recently, laying chickens have attracted considerable attention as an alternative source of antibodies for the prevention and treatment of infectious GI diseases. After immunization, the specific antibodies (called IgY) are transported to the egg yolk, from which the IgY then can be separated without sacrificing chickens. A chicken usually lays about 280 eggs in a year, and egg yolk contains 100-150 mg of IgY per yolk, suggesting that more than 40 g of IgY per year can be obtained from each chicken through eggs. IgY is also an alternative to antibiotics for treatment of enteric antibiotic-resistant pathogens. Oral administration of IgY has proved successful for treatment of a variety of GI infections, such as bovine and human rotaviruses, bovine coronavirus, Yersinia ruckeri, enterotoxigenic Escherichia coli, Salmonella spp., Edwardsiella tarda, Staphylococcus, and Pseudomonas. The IgY technology offers great future opportunities for designing prophylactic strategies against infectious GI diseases in humans and animals. However, there is still controversy regarding the stability of IgY through the GI tract. Finding an effective way to protect the antibodies from degradation in the GI tract would open the door for significant advances in IgY technology and nutraceutical applications.

Oral immunisation of chickens using cholera toxin B subunit and Softigen as adjuvants results in high antibody titre in the egg yolk.

Oral immunisation by gavage of laying hens with human immunoglobulin G (IgG) combined with a number of potential adjuvants was performed. The resulting immunospecific egg yolk (IgY) antibodies were quantified by ELISA. The following adjuvants were tested: A Poly(lactide-co-glycolide) (PLG) microspheres, Cholera toxin B-subunit (CTB), CTB conjugated with glutaraldehyde, Dimethyl dioctadecyl ammonium bromide (DDA), and Softigen (pegylated C8/C10 mono/di glyceride). Hens in a positive control group were immunised with human IgG in saline emulsified with an equal volume of Freund's Incomplete Adjuvant. High titres of immunospecific IgY antibodies against human IgG were recorded in the eggs from the chickens immunised orally with the antigen combined with glutaraldehyde conjugated CTB and in the chickens immunised with the antigen combined with Softigen. The present results show that invasive technique related stress could be eliminated/reduced in polyclonal antibody producing animals.

The humoral immune response and the productivity of laying hens kept on the ground or in cages.

The effects of two different keeping systems on the humoral immune response and productivity were compared for 80 laying hens, divided into four groups. Two groups each of 20 hens were kept on the ground and two were kept in cages. All the birds were immunised subcutaneously with human serum immunoglobulin G (IgG) at a dose of 100(microg per injection. The immunisations were performed twice at 4-week intervals. The lipopeptide Pam(3)Cys-Ser-(Lys)(4) was used as an adjuvant at a dose of 0.25mg per injection in one group from each housing system. In the second group from each housing system, the hens were immunised without any adjuvant (antigen control groups). The mean egg yield was significantly higher in both the antigen control group and the adjuvant group, when laying hens were kept in cages. Total egg weight remained constant in both of the housing systems. Keeping hens in cages resulted in higher mean specific antibody titres and mean immunoglobulin Y concentrations in the egg yolk.

Isolation of immunoglobulin from egg yolk by anionic polysaccharides.

Isolation conditions of immunoglobulin in egg yolk (IgY) were optimized by the addition of various levels of Na-alginate (Alg), lambda-carrageenan (lambda-Cg), Na-carboxymethyl cellulose (CMC), and pectin (PC) to 6-fold diluted yolk. The mixtures were then reacted at pH 4.0-6.0 for 30 min. The optimal isolation conditions of IgY for Alg, lambda-Cg, and CMC were at the 0.1% level and at pH 5.0, while those for PC were at the 0.15% level and at the same pH. The remaining lipid and remaining protein in the supernatants thus obtained was 0.5-3.8% and 10-17%, respectively, and more than 90% of lipoproteins were precipitated. The IgY recovery was determined to be 33-74% by means of single radial immunodiffusion method when IgY was isolated under the optimal conditions. PC showed the best recovery of IgY, while lambda-Cg provided the least. The interactions between polysaccharides and lipoproteins were mainly ionic bonds, hydrophobic interactions, and hydrogen bonds as determined by the addition (0-2.0 M) of NaSCN or urea to the polysaccharide-lipoprotein precipitates.

Isolation of bovine immunoglobulin G subclasses from milk, colostrum, and whey using immobilized egg yolk antibodies.

Immunoaffinity columns were made with specific egg yolk immunoglobulin (Ig) Y against bovine IgG1 and IgG2 and were used to isolate pure IgG1 and IgG2 from Cheddar cheese whey or colostrum. About 10% of the IgY was specific for IgG, and 3% of the IgY was subclass-specific after hyperimmunization of laying hens with either IgG1 or IgG2. Up to 38% of the potential binding capacity of IgY was obtained after immobilization by reductive amination. The IgY columns were stable, and one column could be reused for more than 50 times for over a year with minimal loss in binding capacity. Milk that was free of either IgG subclass was successfully produced by the selective removal of IgG1 or IgG2 subclasses. Double-immunodiffusion analysis confirmed the isolation of subclasses from whey and colostrum and also confirmed that their removal from milk was specific.

[Evaluation of the reproducibility of the MAST technique for pneumoallergens and food allergens. Biological study]. / Evaluation de la fiabilité de la technique MAST pour les pneumallergènes et les trophallergènes. Etude biologique.

MAST-Cla reagent is used in France for now 10 years for the specific IgE determinations. Due to the different modifications of the manufactoring process we checked here the actual sensitivity of this test as compared to the results obtained by the CAP RAST RIA. The mean sensitivities related to the class 1 limit obtained by successive dilutions of the tested sera were respectively for the major aero-allergens and food allergens 0.40 kUI/l and 0.49 kUI/l. Four major allergens (grass pollen, house dust mite, egg yolk and milk) we observed a low background for 10 control subjects, the mean values (n = 6) related to a low concentration of grass pollen specific IgE (0.5 kUl/l) being significant (p < 0.01).