Passive immunization against dental plaque formation in humans: effect of a mouth rinse containing egg yolk antibodies (IgY) specific to Streptococcus mutans

IgYs: on her majesty's secret service

There has been an increasing interest in using Immunoglobulin Y (IgY) antibodies as an alternative to "classical" antimicrobials. Unlike traditional antibiotics, they can be utilized on a continual basis without leading to the development of resistance. The veterinary IgY antibody market is growing because of the demand for minimal antibiotic use in animal production. IgY antibodies are not as strong as antibiotics for treating infections, but they work well as preventative agents and are natural, nontoxic, and easy to produce. They can be administered orally and are well tolerated, even by young animals. Unlike antibiotics, oral IgY supplements support the microbiome that plays a vital role in maintaining overall health, including immune system function. IgY formulations can be delivered as egg yolk powder and do not require extensive purification. Lipids in IgY supplements improve antibody stability in the digestive tract. Given this, using IgY antibodies as an alternative to antimicrobials has garnered interest. In this review, we will examine their antibacterial potential.

IgY Antibodies as Biotherapeutics in Biomedicine

Since the discovery of antibodies by Emil Von Behring and Shibasaburo Kitasato during the 19th century, their potential for use as biotechnological reagents has been exploited in different fields, such as basic and applied research, diagnosis, and the treatment of multiple diseases. Antibodies are relatively easy to obtain from any species with an adaptive immune system, but birds are animals characterized by relatively easy care and maintenance. In addition, the antibodies they produce can be purified from the egg yolk, allowing a system for obtaining them without performing invasive practices, which favors the three “rs” of animal care in experimentation, i.e., replacing, reducing, and refining. In this work, we carry out a brief descriptive review of the most outstanding characteristics of so-called “IgY technology” and the use of IgY antibodies from birds for basic experimentation, diagnosis, and treatment of human beings and animals.

A Comparative Evaluation of Xylitol Chewing Gum and a Combination of IgY + Xylitol Chewable Tablet on Salivary Streptococcus mutans Count in Children: A Double-blind Randomized Controlled Trial

Aim

The study was designed for evaluation and comparison of the efficacy of Xylitol chewing gum and a combination of IgY + Xylitol chewable tablet (Nodecay ^TM) against the “salivary Streptococcus mutans ” count in children.

Materials and methods

About 120 children belonging to 6-12 years age-group were enrolled into this “double-blind randomized control clinical trial” according to the selection criteria. They were randomly assigned to three groups of 40 each: Group I-Xylitol chewing gum, Group II-IgY + Xylitol Chewable tablet (Nodecay ^TM), and Group III-Control. Children in all the groups had to chew the gum/tablet twice daily for 5 minutes during the 15-day period. The salivary samples at baseline, 15 days, 1, 2, and 3 months were inoculated on mitis salivarius bacitracin agar with potassium tellurite medium and the number of colony-forming units (CFUs) of Streptococcus mutans were determined. The data obtained was subjected to statistical analysis.

Result

There was a “significant” difference in the number of “S. mutans CFUs” amongst the three groups at 15 days, 1st month, 2nd month, 3rd month with highest levels of S. mutans CFUs in Group III-Control and least in Group II-IgY + Xylitol (Nodecay^TM).

Conclusion

The combination of IgY + Xylitol (Nodecay^TM) when administered for 15 days had significant efficacy against “S. mutans” when compared to Xylitol and control group.

Clinical significance

Passive immunization with immunoglobulin Y is known not only to decrease the S. mutans count but also confers extended immunity by preventing recolonization of the tooth surface by persistence of the antibodies in saliva.

How to cite this article

Jain RL, Tandon S, Rai TS, et al. A Comparative Evaluation of Xylitol Chewing Gum and a Combination of IgY + Xylitol Chewable Tablet on Salivary Streptococcus mutans Count in Children: A Double-blind Randomized Controlled Trial. Int J Clin Pediatr Dent 2022;15(S-2):S212-S220.

Immunoglobulin Y for Potential Diagnostic and Therapeutic Applications in Infectious Diseases

Antiviral, antibacterial, and antiparasitic drugs and vaccines are essential to maintaining the health of humans and animals. Yet, their production can be slow and expensive, and efficacy lost once pathogens mount resistance. Chicken immunoglobulin Y (IgY) is a highly conserved homolog of human immunoglobulin G (IgG) that has shown benefits and a favorable safety profile, primarily in animal models of human infectious diseases. IgY is fast-acting, easy to produce, and low cost. IgY antibodies can readily be generated in large quantities with minimal environmental harm or infrastructure investment by using egg-laying hens. We summarize a variety of IgY uses, focusing on their potential for the detection, prevention, and treatment of human and animal infections.

A Comparative Study on Egg Yolk IgY Production with Different Adjuvants and their Inhibitory Effects on Staphylococcus aureus

Objectives: Atopic dermatitis (AD) is one of the most common skin disorders in infants and children and is often aggravated by increased Staphylococcus aureus (S. aureus) colonization. An inhibitory effect of a specific egg yolk antibody (IgY) on S. aureus growth was demonstrated in this study. Furthermore, the effects of water- or oil-based adjuvants on the preparation of anti-S. aureus IgY and hen immunization were compared. Methods: Hens were immunized intramuscularly with formalin-killed S. aureus mixed with either a water-soluble polysaccharide λ-carrageenan, oil-based Freund's complete adjuvant (FCA), or Freund's incomplete adjuvant (FIA). Anti-S. aureus IgYs (FIA-IgY, FCA/FIA-IgY, and λCarra-IgY) were purified from the egg yolk of immunized hen eggs, and the activity of the IgY against S. aureus antigen was measured by ELISA. The proportion of each IgY that was absorbed by S. aureus was also determined. Then, the effect of purified anti-S. aureus IgY on S. aureus growth inhibition was investigated in vitro. Results: The yolk of eggs and purified FIA-IgY from the FIA group showed the highest antibody activity, followed by FCA/FIA-IgY and λCarra-IgY. The proportion of each IgY that was absorbed by S. aureus antigen was as follows: FIA-IgY (18.1%), FCA/FIA-IgY (12.9%), and λCarra-IgY (7.0%). Only FIA-IgY significantly inhibited S. aureus growth in liquid medium. Conclusion: A specific IgY that was produced using the FIA adjutant inhibited S. aureus growth. Although water-soluble λ-carrageenan showed an adjuvant effect on anti-S. aureus IgY induction in egg yolk, but did not inhibit S. aureus growth. The use of the oil adjuvant FIA was necessary in the preparation of anti-S. aureus IgY as a treatment for AD symptoms.

The protective efficacy of specific egg yolk immunoglobulin Y(IgY) against Riemerella Anatipestifer infections

Riemerella anatipestifer (RA) is the significant pathogen of septicemia and duck infectious serositis, diseases which can result in high mortality for ducklings. However, these diseases are difficult to treat because of the bacteria's broad resistance to multiple drugs. The purpose of this study was to produce a specific egg yolk immunoglobulin Y (IgY) targeted to RA, and to evaluate the protective efficacy of this IgY against RA infection. An RA-inactivated vaccine was produced via centrifugation and formalin treatment, using the most predominant serotype 2 wild-type strains in terms of worldwide prevalence. Anti-RA IgY was produced by immunizing Beijing Red No.1 hens with the inactivated vaccine. Enzyme-linked immunosorbent assays showed that the titer levels of anti-RA IgY antibodies increased significantly after exposure. Specific IgY isolated and purified from yolks effectively inhibited the growth of RA in the antibacterial activity assay, which revealed an 80 % reduction of bacteria populations. Animal experiments showed that duckling survival rates were able to reach up to 100 % after the ducklings were treated with 10 mg intramuscular injections of anti-RA IgY from 1 to 12 h after infection. However, the survival rates of ducklings treated with 30 mg of nonspecific IgY at 1 h after infection were 0%. Additionally, ducklings injected once with anti-RA IgY received complete protection in the first week, but the efficacy of this protection almost entirely disappeared after two weeks. The results suggested that specific anti-RA IgY has the potential to improve the degree of protection and responsiveness of ducklings to RA infections and provide them with passive immunity to RA. With further study, this is expected to become a new method for controlling RA infections.

The oral microbiota - a mechanistic role for systemic diseases

Human oral microbiota is the ecological community of commensal, symbiotic, and pathogenic microorganisms found in the oral cavity. Oral microbiota generally exists in the form of a biofilm and plays a crucial role in maintaining oral homeostasis, protecting the oral cavity and preventing disease development. Human oral microbiota has recently become a new focus research for promoting the progress of disease diagnosis, assisting disease treatment, and developing personalised medicines. In this review, the scientific evidence supporting the association that endogenous and exogenous factors (diet, smoking, drinking, socioeconomic status, antibiotics use and pregnancy) modulate oral microbiota. It provides insights into the mechanistic role in which oral microbiota may influence systemic diseases, and summarises the challenges of clinical diagnosis and treatment based on the microbial community information. It provides information for noninvasive diagnosis and helps develop a new paradigm of personalised medicine. All these benefit human health in the post-metagenomics era.

Zika Virus-Specific IgY Results Are Therapeutic Following a Lethal Zika Virus Challenge without Inducing Antibody-Dependent Enhancement

The Zika virus (ZIKV) is a newly emerged pathogen in the Western hemisphere. It was declared a global health emergency by the World Health Organization in 2016. There have been 223,477 confirmed cases, including 3720 congenital syndrome cases since 2015. ZIKV infection symptoms range from asymptomatic to Gullain⁻Barré syndrome and extensive neuropathology in infected fetuses. Passive and active vaccines have been unsuccessful in the protection from or the treatment of flaviviral infections due to antibody-dependent enhancement (ADE). ADE causes an increased viral load due to an increased monocyte opsonization by non-neutralizing, low-avidity antibodies from a previous dengue virus (DENV) infection or from a previous exposure to ZIKV. We have previously demonstrated that polyclonal avian IgY generated against whole-killed DENV-2 ameliorates DENV infection in mice while not inducing ADE. This is likely due to the inability of the Fc portion of IgY to bind to mammalian Fc receptors. We have shown here that ZIKV oligoclonal IgY is able to neutralize the virus in vitro and in IFNAR-/- mice. The concentration of ZIKV-specific IgY yielding 50% neutralization (NT50) was 25 µg/mL. The exposure of the ZIKV, prior to culture with ZIKV-specific IgY or 4G2 flavivirus-enveloped IgG, demonstrated that the ZIKV-specific IgY does not induce ADE. ZIKV IgY was protective in vivo when administered following a lethal ZIKV challenge in 3-week-old IFNAR-/- mice. We propose polyclonal ZIKV-specific IgY may provide a viable passive immunotherapy for a ZIKV infection without inducing ADE.

Preparation and Application of Egg Yolk Antibodies Against Chinese Sacbrood Virus Infection

Chinese sacbrood virus (CSBV) infects Apis cerana larvae, resulting in the inability of the larvae to pupate and their consequent death, which may pose a serious threat to entire colonies. As there is no effective medical treatment for CSBV infections, further studies are necessary. In this study, an effective treatment for CSBV is described, based on a specific immunoglobulin Y (IgY) from egg yolk against CSBV. The inactivated vaccine was produced by ultracentrifugation and formalin treatment, using CSBV purified from a natural outbreak. The specific IgY was produced by immunization of white leghorn hens with the vaccine. An enzyme-linked immunosorbent assay using purified CSBV as the coating antigen revealed that the anti-CSBV IgY titer began increasing in the egg yolk on the 14th day post-immunization, reaching a peak on day 42, and anti-CSBV IgY remained at a high level until day 91. IgY isolated from the combinations of egg yolk collected between days 42-91 was purified by PEG and ammonium sulfate precipitation. In three repeated protection experiments using A. cerana larvae inoculated with CSBV, the survival rate of larvae was more than 80%, and the titer of anti-CSBV IgY was more than 25 and 24 when the larvae were fed IgY 24 h after and before inoculation with CSBV, respectively. Therefore, 400 colonies infected with CSBV were treated by feeding sugar containing IgY solutions with an antibody titer of 25, and the cure rate was 95-100%. Three hundred susceptible colonies were protected by feeding the larvae with sugar containing IgY solutions with an antibody titer of 24, and the protection rate was 97%. The results clearly suggest that a specific IgY was obtained from hens immunized with an inactivated-CSBV vaccine; this may be a novel method for controlling CSBV infection.

Effects of specific egg yolk immunoglobulin on pan-drug-resistant Acinetobacter baumannii

With the growing emergence of pan-drug-resistant Acinetobacter baumannii (PDR-Ab) strains in clinical, new strategies for the treatment of PDR-Ab infections are urgently needed. Egg yolk immunoglobulin (IgY) as a convenient and inexpensive antibody has been widely applied to the therapy of infectious diseases. The aim of this study was to produce IgY specific to PDR-Ab and investigate its antibacterial effects in vitro and in vivo. IgYs specific to two PDR-Ab strains were produced by immunizing hens with formaldehyde inactivated PDR-Ab cells and isolated from yolks with a purity of 90% by water dilution, salt precipitations and ultrafiltration. IgYs showed high titers when subjected to an ELISA and inhibited the growth of PDR-Ab in a dose-dependent manner in liquid medium. Scanning electron microscopy assay showed structural modification and aggregation of PDR-Ab treated with specific IgYs. Freshly cultured PDR-Ab cells were nasally inhaled in BALB/c mice to induce acute pneumonia. The infected mice were intraperitoneally injected with specific IgYs using cefoperazone/sulbactam and dexamethasone as positive controls. The IgYs specific to PDR-Ab lowered the mortality of mice with PDR-Ab-induced acute pneumonia, decreased the level of TNF-α and IL-1β in serum and reduced inflammation in lung tissue. Specific IgY has the potential to be used as a new therapeutic approach for the treatment of A. baumannii-induced infections.

Inhibitory effects of rHP-NAP IgY against Helicobacter pylori attachment to AGS cell line

Helicobacter pylori is a major human pathogen related to gastric adenocarcinoma and gastroduodenal diseases. Treatment of H. pylori infections is complicated by the rise of antibiotic resistance, necessitating investigation of alternative therapies. One such alternative is passive immunization by oral administration of antibacterial immunoglobulin. In the present study, chicken immunoglobulin (IgY) was used for passive immunotherapy against a major virulence factor of H. pylori, namely recombinant HP-Nap protein. Recombinant HP-Nap was prepared and used to immunize hens. IgY was purified from the eggs by polyethylene glycol precipitation method with a total IgY-HP-NAP yield of 30 mg per egg. The inhibitory effect of specific IgY on H. pylori attachment was investigated in AGS cell line infected by the bacteria. The results demonstrate the potent effect of IgY- HP-NAP in inhibition of H. pylori attachment to the AGS cells.

Anti-Pseudomonas aeruginosa IgY antibodies promote bacterial opsonization and augment the phagocytic activity of polymorphonuclear neutrophils

Moderation of polymorphonuclear neutrophils (PMNs) as part of a critical defense against invading pathogens may offer a promising therapeutic approach to supplement the antibiotic eradication of Pseudomonas aeruginosa infection in non-chronically infected cystic fibrosis (CF) patients. We have observed that egg yolk antibodies (IgY) harvested from White leghorn chickens that target P. aeruginosa opsonize the pathogen and enhance the PMN-mediated respiratory burst and subsequent bacterial killing in vitro. The effects on PMN phagocytic activity were observed in different Pseudomonas aeruginosa strains, including clinical isolates from non-chronically infected CF patients. Thus, oral prophylaxis with anti-Pseudomonas aeruginosa IgY may boost the innate immunity against Pseudomonas aeruginosa in the CF setting by facilitating a rapid and prompt bacterial clearance by PMNs.

DNA-templated microwave-hydrothermal synthesis of nanostructured hydroxyapatite for storing and sustained release of an antibacterial protein

Hydroxyapatite nanostructured materials are prepared by a DNA-templated microwave-hydrothermal method and used for IgY loading/release and antibacterial study.

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.

Effects of soybean milk, chitosan, and anti-Streptococcus mutans IgY in malnourished rats' dental biofilm and the IgY persistency in saliva

OBJECTIVE

This study aims to evaluate the eff ect of soybean milk containing a combination of anti-Streptococcus mutans IgY and chitosan to the colonization of S. mutans in the saliva and to the IgY persistency in the saliva.

MATERIALS AND METHODS

Experimental malnourished Sprague-Dawley rats were fed with soybean milk that is enriched with anti-S. mutans IgY and chitosan. After 15 days of feeding, we evaluated the S. mutans in dental biofilm, in addition to the persistency level of anti-S. mutans IgY.

RESULTS

The rats that received soybean milk supplemented with anti-S. mutans IgY had the lowest number of S. mutans colonies (p < 0.05). Anti-S. mutans IgY was detected in saliva after 15 days of feeding.

CONCLUSIONS

Soybean milk supplemented with anti-S. mutans IgY and chitosan could signifi cantly reduce S. mutans biofilm, and the supplemented anti-S. mutans IgY persisted in these rats' saliva following the feeding period.

Bioactive peptides from egg: a review

Purpose

– The aim of the article was to focus on various peptides identified in the egg and their probable application as novel ingredients in the development of functional food products. Bioactive peptides of egg origin have attracted increasing interest as one of the prominent candidates for development of various health-promoting functional and designer foods.

Design/methodology/approach

– Traditionally known as a source of highly valuable proteins in human nutrition, eggs are nowadays also considered as an important source of many bioactive peptides which may find wide application in medicine and food production. These specific protein fragments from egg proteins which, above and beyond their nutritional capabilities, have a positive impact on the body’s function or condition by affecting the digestive, endocrine, cardiovascular, immune and nervous systems, and may ultimately influence health.

Findings

– Several peptides that are released in vitro or in vivo from egg proteins have been attributed to different health effects, including antihypertensive effects, antimicrobial properties, antioxidant activities, anticancer activity, immunomodulating activity, antiadhesive properties and enhancement of nutrient absorption and/or bioavailability. Extensive research has been undertaken to identify and characterize these biologically active peptides of egg origin which has changed the image of egg as a new source of biologically active ingredients for the development of functional foods with specific benefits for human health and treatment and prevention of diseases.

Originality/value

– The paper mainly describes the above-stated properties of bioactive peptides derived from egg proteins.

An amorphous calcium phosphate nanocomposite for storing and sustained release of IgY protein with antibacterial activity

Amorphous calcium phosphate nanospheres with/without La doping are prepared and used for IgY storing, sustained release and antibacterial study.

Passive Immunization

Whereas active immunity refers to the process of exposing the individual to an antigen to generate an adaptive immune response, passive immunity refers to the transfer of antibodies from one individual to another. Passive immunity provides immediate but short-lived protection, lasting several weeks up to 3 or 4 months. Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta or from breast milk to the gut of the infant. It can also be produced artificially, when antibody preparations derived from sera or secretions of immunized donors or, more recently, different antibody producing platforms are transferred via systemic or mucosal route to nonimmune individuals. Passive immunization has recently become an attractive approach because of the emergence of new and drug-resistant microorganisms, diseases that are unresponsive to drug therapy and individuals with an impaired immune system who are unable to respond to conventional vaccines. This chapter addresses the contributions of natural and artificial acquired passive immunity in understanding the concept of passive immunization. We will mainly focus on administration of antibodies for protection against various infectious agents entering through mucosal surfaces.

Protective effect of an egg yolk-derived immunoglobulin (IgY) against Prevotella intermedia-mediated gingivitis

AIMS

To investigate the effects of an egg yolk-derived immunoglobulin (IgY) specific to Prevotella intermedia in vitro and in vivo.

METHODS AND RESULTS

An IgY specific to P. intermedia was produced by immunizing hens with formaldehyde-inactivated P. intermedia and showed high titres when subjected to an ELISA. The obtained IgY inhibited the growth of P. intermedia in a dose-dependent manner at concentrations from 1 to 20 mg ml(-1) in Center for Disease Control and Prevention liquid medium. Forty rats were challenged with P. intermedia on gingivae and then randomly divided into four groups, which were syringed respectively with phosphate-buffered saline, 1 mg ml(-1) of tinidazole, 20 mg ml(-1) of nonspecific IgY and 20 mg ml(-1) of the IgY specific to P. intermedia at a dosage of 300 μl per day. Gingival index (GI), plaque index (PI), bleeding on probing (BOP), counts of white blood cell (WBC) and histopathological slide of the gums were measured after treatment for 15 days. The gingivitis rats treated with the IgY specific to P. intermedia showed significantly decreased GI, PI, BOP and WBC (P < 0·05). Gum histopathology of the treated rats demonstrated a superior protective effect of the specific IgY on P. intermedia-mediated gingivitis.

CONCLUSIONS

A new immunoglobulin specific to P. intermedia was developed from egg yolk. This specific IgY can dose-dependently inhibit the growth of P. intermedia and protect rats from gingivitis induced by P. intermedia.

SIGNIFICANCE AND IMPACT OF THE STUDY

The new IgY has potential for the treatment of P. intermedia-mediated gingivitis.

Effect of essential oils containing and alcohol-free chlorhexidine mouthrinses on cariogenic micro-organisms in human saliva

OBJECTIVE

The aim of this study was to evaluate the effect on mutans streptococci and lactobacilli in saliva of mouthrinsing with essential oils and an alcohol-free chlorhexidine.

MATERIALS AND METHOD

Twenty healthy volunteers (mean age 59 years) participated in the double-blind randomized cross-over study. Three mouthrinses were used in 16 days rinsing periods in addition to their regular mechanical oral hygiene: a solution with essential oils (EO; Listerine), a solution with alcohol-free chlorhexidine (CHX; Paroex) and water (negative control). The mouthrinse periods were separated by 3-month washout periods. At days 0 (baseline) and 17 (end) of each mouthrinse period, paraffin stimulated whole saliva was collected in order to analyse CFU/ml saliva of mutans streptococci and lactobacilli.

RESULTS

Only the CHX rinse showed a significant difference for CFU mutans streptococci between baseline and end (p = 0.004). The CFU mutans streptococci at the end of the rinse periods showed statistically significant differences between CHX vs EO (p = 0.039) and CHX vs water (p = 0.022). The difference in CFU lactobacilli between baseline and end was significant for CHX (p = 0.031), but not for the other rinses. No statistically significant differences for lactobacilli were found at the end of the rinse periods between the mouthrinses.

CONCLUSION

A significant reduction in amount of cariogenic bacteria in saliva was observed after 16 days of alcohol-free chlorhexidine mouthrinse but not after the essential oils rinse. The high number of participant's not changing to a bacterial class with a reduced number of micro-organisms showed that both rinses had little clinical significance as a caries preventing treatment method, which can decrease the number of CFU cariogenic micro-organisms.

Oral passive IgY-based immunotherapeutics: a novel solution for prevention and treatment of alimentary tract diseases

This commentary summarizes the laboratory investigations and clinical trials published recently involving per-oral application of IgY supplemented food for specific orogastrointestinal disease prevention and control purposes. The prolonged use and misuse of conventional antibacterial drugs has spawned antibiotic resistant microbes prompting scientists to search for other germ-killing options. In particular, the use of IgY as a novel mode of immunotherapy using oral chicken immunoglobulin (IgY) to confer passive immunity has gained much interest as an inexpensive non-antibiotic alternative for the prophylaxis and treatment of a wide variety of infectious diseases. The stability of IgY in the orogastrointestinal tract and its safety profile has been well-documented. IgY has been used in the treatment or prevention of dental caries, periodontitis and gingivitis, gastritis and gastric ulcer, oral thrush and infant rotavirus diarrhea. The recent clinical trials on IgY with encouraging results has catapulted into the market novel nutraceutical or health supplements for therapeutic or prophylactic intervention based on the consumption of mono-specific or mixed IgY formulations. With recent trends in consumer preference for natural materials to alleviate health concerns, the increasing healthcare costs and the recent advances in drug delivery systems, IgY is likely to shift from its mainly functional food status toward pharmaceuticalization in the foreseeable future.

Avian IgY antibodies and their recombinant equivalents in research, diagnostics and therapy

The generation and use of avian antibodies is of increasing interest in a wide variety of applications within the life sciences. Due to their phylogenetic distance, mechanisms of immune diversification and the way in which they deposit IgY immunoglobulin in the egg yolk, chickens provide a number of advantages compared to mammals as hosts for immunization. These advantages include: the one-step purification of antibodies from egg yolk in large amounts facilitates having a virtually continuous supply; the epitope spectrum of avian antibodies potentially grants access to novel specificities; the broad absence of cross-reactivity with mammalian epitopes avoids assay interference and improves the performance of immunological techniques. The polyclonal nature of IgY antibodies has limited their use since avian hybridoma techniques are not well established. Recombinant IgY, however, can be generated from mammalian monoclonal antibodies which makes it possible to further exploit the advantageous properties of the IgY scaffold. Moreover, cloning and selecting the immune repertoire from avian organisms is highly efficient, yielding antigen-specific antibody fragments. The recombinant approach is well suited to circumvent any limitations of polyclonal antibodies. This review presents comprehensive information on the generation, purification, modification and applications of polyclonal and monoclonal IgY antibodies.

Passive immune neutralization strategies for prevention and control of influenza A infections

Although vaccination significantly reduces influenza severity, seasonal human influenza epidemics still cause more than 250,000 deaths annually. Vaccine efficacy is limited in high-risk populations such as infants, the elderly and immunosuppressed individuals. In the event of an influenza pandemic (such as the 2009 H1N1 pandemic), a significant delay in vaccine availability represents a significant public health concern, particularly in high-risk groups. The increasing emergence of strains resistant to the two major anti-influenza drugs, adamantanes and neuraminidase inhibitors, and the continuous circulation of avian influenza viruses with pandemic potential in poultry, strongly calls for alternative prophylactic and treatment options. In this review, we focus on passive virus neutralization strategies for the prevention and control of influenza type A viruses.

Cloning and characterization of heavy and light chain genes encoding the FimA-specific monoclonal antibodies that inhibit Porphyromonas gingivalis adhesion

FimA of Porphyromonas gingivalis, a major pathogen in periodontitis, is known to be closely related to the virulence of these bacteria and has been suggested as a candidate for development of a vaccine against periodontal disease. In order to develop a passive immunization method for inhibiting the establishment of periodontal disease, B hybridoma clones 123-123-10 and 256-265-9, which produce monoclonal antibodies (Mabs) specific to purified fimbriae, were established. Both mAbs reacted with the conformational epitopes displayed by partially dissociated oligomers of FimA, but not with the 43 kDa FimA monomer. Gene sequence analyses of full-length cDNAs encoding heavy and light chain immunoglobulins enabled classification of the genes of mAb 123-123-10 as members of the mVh II (A) and mVκ I subgroups, and those of mAb 256-265-9 as members of the mVh III (D) and mVκ I subgroups. More importantly, 50 ng/mL of antibodies purified from the culture supernatant of antibody gene-transfected CHO cells inhibited, by approximately 50%, binding of P. gingivalis to saliva-coated hydroxyapatite bead surfaces. It is expected that these mAbs could be used as a basis for passive immunization against P. gingivalis-mediated periodontitis.

Development of a monoclonal antibody against glucosyltransferase D of Streptococcus mutans GS 5

Glucosyltransferases GtfB, GtfC, and GtfD of Streptococcus mutans are virulent factors involved in dental caries. Consequently, they are considered to be target molecules in the development of vaccines against dental caries. Among them, GtfD plays a significant role in the sucrose-dependent cellular adhesion of S. mutans, and a number of studies have suggested that the N-terminus of GtfD is an important part of its role in enzymatic activity. In this study, we generated monoclonal antibodies against the N-terminus of GtfD (anti-GtfDN antibody) in an initial attempt to investigate its preventive efficacy against dental caries. To obtain anti-GtfDN monoclonal antibodies, the gene for the N-terminus of gtfD (2 kb) was cloned into an Escherichia coli expression vector, pQE30; then the expressed protein (about 75 kDa) was purified. The purified GtfDN protein was injected into BALB/c mice, and hybridoma clones were established. We obtained three hybridoma clones (HDN9, HDN11, and HDN28) capable of producing anti-GtfDN antibodies. Their binding specificity was characterized by ELISA, dot blot, and Western blot analysis after purification using affinity column chromatography. The isotype of the monoclonal antibodies was confirmed to be IgG2a.

Process for coproduction of crude immunoglobulin y and high-density lipoproteins from hen egg yolk

High value-added products from hen egg are receiving increasing attention from both egg academic and industrial circles due to their potential applications in research and medicine as well as the benefits they bring to egg-breaking industries. This paper reports a simple method for the preparation of immunoglobulin Y (IgY) and high-density lipoproteins (HDL) from hen egg yolk. A water dilution method coupled with (NH4)2SO4 precipitation was employed to prepare the two target proteins. SDS-PAGE under reducing or nonreducing conditions and liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS) were used to characterize the two products. Western blotting and histobiochemical staining were utilized to qualitatively analyze IgY and HDL, respectively. The purities of prepared IgY and HDL were detected by ELISA and a direct high-density lipoprotein-cholesterol assay, respectively. Results show that dilution times 15 makes IgY and HDL separate well from each other. Western blotting proves IgY has an immunocompetence similar to that of human IgG. Histobiochemical staining shows HDL is composed of sugar, lipid, and protein. The quantitative evaluation of the products indicates that approximately 3 kg of IgY and 2 kg of HDL with purities of 72.7 and 71.9%, respectively, are available from 1 ton of shell eggs via this process.

Passive protection effect of chicken egg yolk immunoglobulins on enterovirus 71 infected mice

The objective of this study is to evaluate the passive protective efficiency of immunoglobulin in yolk (IgY) specific against human enterovirus type 71 (EV71). The antibody was raised by intramuscular immunization to 10 White Leghorn hens, with inactivated human EV71 serving as the antigen. The titer and specificity of the antibody were analyzed from purified IgY in the egg yolks of immunized hens. Results indicate that the titer of IgY specific against EV71 increased from the third week after the first immunization. The content of total IgY was 190 ± 26 mg/yolk, with an average concentration of specific IgY of 6.34 ± 3.38 mg/yolk in the eggs from 3 to 18 wk after immunization. The results of the neutralization effect of specific IgY in EV71-challenged mice demonstrate that the EV71-specific IgY, either by intraperitoneal injection or oral administration, was able to significantly reduce the morbidity and mortality in EV71 infected mice pups.

Prophylactic and therapeutic efficacy of avian antibodies against influenza virus H5N1 and H1N1 in mice

BACKGROUND

Pandemic influenza poses a serious threat to global health and the world economy. While vaccines are currently under development, passive immunization could offer an alternative strategy to prevent and treat influenza virus infection. Attempts to develop monoclonal antibodies (mAbs) have been made. However, passive immunization based on mAbs may require a cocktail of mAbs with broader specificity in order to provide full protection since mAbs are generally specific for single epitopes. Chicken immunoglobulins (IgY) found in egg yolk have been used mainly for treatment of infectious diseases of the gastrointestinal tract. Because the recent epidemic of highly pathogenic avian influenza virus (HPAIV) strain H5N1 has resulted in serious economic losses to the poultry industry, many countries including Vietnam have introduced mass vaccination of poultry with H5N1 virus vaccines. We reasoned that IgY from consumable eggs available in supermarkets in Vietnam could provide protection against infections with HPAIV H5N1.

METHODS AND FINDINGS

We found that H5N1-specific IgY that are prepared from eggs available in supermarkets in Vietnam by a rapid and simple water dilution method cross-protect against infections with HPAIV H5N1 and related H5N2 strains in mice. When administered intranasally before or after lethal infection, the IgY prevent the infection or significantly reduce viral replication resulting in complete recovery from the disease, respectively. We further generated H1N1 virus-specific IgY by immunization of hens with inactivated H1N1 A/PR/8/34 as a model virus for the current pandemic H1N1/09 and found that such H1N1-specific IgY protect mice from lethal influenza virus infection.

CONCLUSIONS

The findings suggest that readily available H5N1-specific IgY offer an enormous source of valuable biological material to combat a potential H5N1 pandemic. In addition, our study provides a proof-of-concept for the approach using virus-specific IgY as affordable, safe, and effective alternative for the control of influenza outbreaks, including the current H1N1 pandemic.

Proteomic characterization of IgY preparations purified with a water dilution method

Antigen-specific chicken IgY antibodies have been used for oral immunotherapy as an alternative or complement to antibiotics in several studies. The water dilution (WD) method has several advantages for purifying IgY. It is rapid, efficient, suitable for large-scale production, and nothing but water is added. The water-soluble fraction contains other proteins and lipids besides IgY. The protein content was characterized by two-dimensional gel electrophoresis (2DGE) and nanoflow liquid chromatography coupled offline to matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (nanoLC-MALDI TOF/TOF MS). Protein analysis was complicated due to the large dynamic concentration range, but 26 proteins could be identified. The relative protein concentrations in different batches were very similar according to protein patterns on 1D gels and protein concentration determinations. Thus, the purification method has a high reproducibility. The concentrations of cholesterols and triglycerides were low and should not have an effect on the plasma levels of treated patients. Purification of IgY for oral use with WD is therefore a recommended method.

Activity of anti-Porphyromonas gingivalis egg yolk antibody against gingipains in vitro

INTRODUCTION

We investigated the effect of anti-Porphyromonas gingivalis egg yolk antibody against gingipains [immunoglobulin Y (IgY)-GP] on gingipain activity in vitro.

METHODS

IgY-GP was isolated from the yolks of White Leghorn hens immunized with purified gingipains. Control antibody (IgY) was isolated from the yolks of non-immunized hens. Gingipain activity was assessed according to the rate of enzymatic substrate hydrolysis. Human epithelial cells were cultured with or without gingipains and with gingipains pretreated with either IgY-GP or IgY.

RESULTS

Hydrolytic activity decreased in the presence of IgY-GP. Cells incubated with gingipains showed a dose-dependent loss of adhesion activity. Pretreatment of gingipains with IgY-GP was associated with strong inhibition of cell detachment, whereas pretreatment with IgY was not.

CONCLUSION

Our findings suggest that IgY-GP may be an effective immunotherapeutic agent in the treatment of periodontitis.

In vitro effects of a fraction separated from Polygonum cuspidatum root on the viability, in suspension and biofilms, and biofilm formation of mutans streptococci

Polygonum cuspidatum (Polygonaceae) has traditionally been used in folk medicine to control oral diseases. Nevertheless, there are no reports related to its possible effect on the diseases, particularly on biofilm-related diseases such as dental caries. In this study, we evaluated in vitro effects of a fraction separated from Polygonum cuspidatum root on the viability, in both suspension and biofilms, and the biofilm formation of mutans streptococci. The separated fraction (F1) showed bacteriostatic and bactericidal activity against mutans streptococci in suspension, with minimum inhibitory concentration (MIC) range of 31.3-250 microg/ml and minimum bactericidal concentration (MBC) range of 0.5-1 mg/ml. At a concentration of 1.5 mg/ml, F1 killed approximately 2 log(10)CFU/ml of Streptococcus mutans and Streptococcus sobrinus after 2h of exposure. In biofilms, F1 also inhibited the viability of Streptococcus mutans and Streptococcus sobrinus, dependent on the biofilm age, the concentration of F1, and the treatment time. Four hours of exposure to 1.5 mg/ml F1 reduced the viable counts of Streptococcus mutans and Streptococcus sobrinus by greater than 2 log(10)CFU/disc. Furthermore, at sub-MIC levels, F1 inhibited biofilm formation by Streptococcus mutans and Streptococcus sobrinus in a dose-dependent fashion. Based on the preliminary phytochemical analysis, the activity of F1 may be related to the presence of anthraquinones, cardiac glycosides, terpenoids, and phenolics. These results indicate that F1 is probably useful in the control of oral biofilms and subsequent dental caries development.

More Than 10 Years' Continuous Oral Treatment with Specific Immunoglobulin Y for the Prevention ofPseudomonas aeruginosaInfections: 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.

Protection of Carassius auratus Gibelio against infection by Aeromonas hydrophila using specific immunoglobulins from hen egg yolk

Specific immunoglobulin (IgY) from egg yolk against Aeromonas hydrophila was produced by immunization of White Leghorn hens with formalin-killed whole cells of A. hydrophila. ELISA test using A. hydrophila as the coating antigen revealed that the specific antibody titer started to increase in the egg yolk at the 13th day post-immunization (P/N=2.18), reached the peak at the 56th day (P/N=13.82), and remained at high level until day 133 (P/N=7.03). The antibody was purified by saturated ammonium sulphate with a recovery rate of 63.5%. The specific IgY inhibited the growth of A. hydrophila at a concentration of 1.0 mg/ml during the 18 h incubation. Pre-treatment of polyploid gibel carps Carassius auratus Gibelio with specific IgY had a protection rate of 60% (6/10) against challenge with A. hydrophila, while none of the fishes in the control groups receiving sterile phosphate buffered saline (PBS) or non-specific IgY survived the challenge. Treatment of fishes with the specific IgY 4 h after the challenge also had lower mortality (70%, 7/10), a 30% reduction against the control PBS or non-specific IgY groups (10/10). These results indicate that specific IgY antibodies could be obtained easily from hens immunized with an inactivated A. hydrophila and could provide a novel alternative approach to control of diseases in fishes caused by this organism.

Inhibition of Acid Production in Dental Plaque Bacteria by Green Tea Catechins

The inhibition of acid production from dental plaque and mutans streptococci by epigallocatechin gallate (EGCg), one of the green tea catechins, was examined. The effect of EGCg solution on dental plaque pH was investigated. Subjects rinsed their mouths with 2 mg/ml EGCg solution and then, after 30-min interval, rinsed their mouths with 10% sucrose. Plaque samples were collected at appropriate times and the pH was measured. The pH values of plaque samples from 15 volunteers were significantly higher after treatment with catechin than after treatment with water. EGCg inhibited pH fall when cariogenic bacteria grown in medium with or without sucrose were incubated with sugar. In medium without sucrose, cultured cells were killed time-dependently by EGCg treatment. However, EGCg did not kill cells cultured in medium containing sucrose. Also, EGCg did not kill oral streptococci adhering to a saliva-coated hydroxyapatite disk. EGCg and epicatechin gallate inhibited lactate dehydrogenase activity much more efficiently than epigallocatechin, epicatechin, catechin or gallocatechin. These results suggest that EGCg is effective in reducing acid production in dental plaque and mutans streptococci.

Advances in the value of eggs and egg components for human health

The avian egg is an important source of nutrients, containing all of the proteins, lipids, vitamins, minerals, and growth factors required by the developing embryo, as well as a number of defense factors to protect against bacterial and viral infection. Moreover, eggs are now understood to contain substances with biological functions beyond basic nutrition, and extensive research has been undertaken to identify and characterize these biologically active components. This review mainly focused on biological activities of proteins and peptides derived from egg components. Several biological activities have now been associated with egg components, including novel antimicrobial activities, antiadhesive properties, immunomodulatory, anticancer, and antihypertensive activities, antioxidant properties, protease inhibitors, nutrient bioavailability, and functional lipids, highlighting the importance of egg and egg components in human health and in disease prevention and treatment. Continued research to identify new and existing biological functions of hen egg components will help to define new methods to further improve the value of eggs as a source of numerous biologically active compounds with specific benefits for human and animal health and secure their role in the therapy and prevention of chronic and infectious disease.

Chicken egg yolk antibodies (IgY-technology): a review of progress in production and use in research and human and veterinary medicine

The production of antibodies (Abs) in chickens and the extraction of specific Abs from egg yolk (IgY Abs) are increasingly attracting the interest of the scientific community, as demonstrated by the significant growth of the IgY literature. This review offers detailed and comprehensive information about IgY-technology, including: a) possibilities for hen keeping in accordance with the Three Rs principles; b) new insights into the IgY transfer mechanism from blood to yolk as a biological basis for the technology; c) the comparative characteristics of IgY Abs and IgG Abs; d) the high efficacy of the technique, in view of the extraordinary amount of IgY Ab produced by one hen in one year (between 20 g and 40 g IgY in total); e) comparisons between the efficacies of IgY Abs and IgG Abs (rabbit, sheep, mouse) in several immunological assays; f) immunisation protocols, as well as the most commonly used IgY-extraction procedures; g) new possibilities for application in human and veterinary medicine, including strategies for the treatment of Helicobacter pylori infection or fatal intestinal diseases in children, particularly in poor countries, for reducing the use of antibiotics, and, in Asia and South America, for producing Abs against snake, spider and scorpion venoms; and h) the use of IgY Abs in various fields of research, also taking into consideration recent developments in South America (particularly Argentina and Cuba) and in Asia.

Suppressive effect of functional drinking yogurt containing specific egg yolk immunoglobulin on Helicobacter pylori in humans

Helicobacter pylori is a human pathogen that infects over 50% of the population worldwide. It is the most important etiologic agent of gastroduodenal ulcers and malignancies. Helicobacter pylori urease enzyme is considered the main factor for the organism's colonization in the gastroduodenal mucosa. Hens immunized with the purified urease produce a highly specific anti-H. pylori urease immunoglobulin (IgY-urease) in their egg yolks. Immunoglobulin Y-urease was stable at 60 to 65 degrees C for 30 min and at pH 4.0 for 7 h. Its activity was lost at 80 degrees C for 20 min and at pH 2 for 4 h. Specially designed functional drinking yogurt containing Lactobacillus acidophilus and Bifidobacterium spp. with 1% egg yolk IgY-urease was produced commercially. Immunoglobulin Y-urease activity showed stability in the product up to 7 d, and then decreased to 85% after 3 wk of storage. A clinical study was conducted to determine the effectiveness of IgY-urease yogurt to suppress infection in humans. Forty-two volunteers who tested positive for H. pylori using a 13C-urea breath test were recruited. A total of 450 mL of IgY-urease (test group) or IgY-urease-free yogurt (control group) was consumed in 150-mL portions 3 times daily for 4 wk. Volunteers were tested after 2 and 4 wk; urea breath test values significantly decreased in the test group compared with the control group. The results indicate that suppression of H. pylori infection in humans could be achieved by consumption of drinking yogurt fortified with IgY-urease.