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.

Mucosal Vaccination Against Periodontal Disease: Current Status and Opportunities

Approximately 9 out of 10 adults have some form of periodontal disease, an infection-induced inflammatory disease of the tooth-supporting tissues. The initial form, gingivitis, often remains asymptomatic, but this can evolve into periodontitis, which is typically associated with halitosis, oral pain or discomfort, and tooth loss. Furthermore, periodontitis may contribute to systemic disorders like cardiovascular disease and type 2 diabetes mellitus. Control options remain nonspecific, time-consuming, and costly; largely relying on the removal of dental plaque and calculus by mechanical debridement. However, while dental plaque bacteria trigger periodontal disease, it is the host-specific inflammatory response that acts as main driver of tissue destruction and disease progression. Therefore, periodontal disease control should aim to alter the host's inflammatory response as well as to reduce the bacterial triggers. Vaccines may provide a potent adjunct to mechanical debridement for periodontal disease prevention and treatment. However, the immunopathogenic complexity and polymicrobial aspect of PD appear to complicate the development of periodontal vaccines. Moreover, a successful periodontal vaccine should induce protective immunity in the oral cavity, which proves difficult with traditional vaccination methods. Recent advances in mucosal vaccination may bridge the gap in periodontal vaccine development. In this review, we offer a comprehensive overview of mucosal vaccination strategies to induce protective immunity in the oral cavity for periodontal disease control. Furthermore, we highlight the need for additional research with appropriate and clinically relevant animal models. Finally, we discuss several opportunities in periodontal vaccine development such as multivalency, vaccine formulations, and delivery systems.

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.

Periodontitis and the impact of oral health on the quality of life of psoriatic individuals: a case-control study

AIM

To evaluate the periodontal condition and the impact of oral health on the quality of life (OHRQL) among individuals with and without psoriasis.

METHODS

This case-control study comprised 295 individuals with psoriasis and 359 controls. A full mouth examination was performed for all periodontal clinical parameters. To evaluate OHRQL, the Oral Impact on Daily Performance (OIDP) questionnaire was applied. Data was analyzed using the chi-square, Fischer, Kruskal-Wallis, Mann-Whitney, and Bootstrap intervals tests to determine different profiles in relation to the OIDP.

RESULTS

Individuals with psoriasis had a 1.40 greater chance of having periodontitis than controls (OR = 1.40 95%CI: 1.01-1.93; p = 0.019). Individuals with psoriasis with periodontitis (+P) had greater impacts on OHRQL (13.76 ± 15.58), when compared with those without periodontitis (-P) (4.83 ± 8.25; p < 0.001). Additionally, psoriasis +P stage III/IV patients (13.94 ± 15.68) had worse indicators than controls -P (9.49 ± 22.54; p = 0.001). The final multivariate model demonstrated higher OIDP scores related to the following variables: diabetes, anxiolytics use, periodontitis, and psoriasis, showing worse OHRQoL.

CONCLUSIONS

This study demonstrated an important risk association between psoriasis and periodontitis, as both diseases demonstrated worse OHRQL indicators. Moreover, the severity of periodontitis and psoriasis significantly increased these negative impacts.

CLINICAL RELEVANCE

Practical implications: Multidisciplinary interaction is desirable to improve the impact of these diseases on the QoL of individuals with psoriasis and periodontitis.

Can Immunization of Hens Provide Oral-Based Therapeutics against COVID-19?

In the current worldwide pandemic situation caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and the newest coronavirus disease (COVID-19), therapeutics and prophylactics are urgently needed for a large population. Some of the prophylaxis strategies are based on the development of antibodies targeting viral proteins. IgY antibodies are a type of immunoglobulin present in birds, amphibians, and reptiles. They are usually obtained from egg yolk of hyper-immunized hens and represent a relatively inexpensive source of antibodies. Specific IgY can be produced by immunizing chickens with the target antigen and then purifying from the egg yolk. Chicken IgY has been widely explored as a clinical anti-infective material for prophylaxis, preventive medicine, and therapy of infectious diseases. Administered non-systemically, IgY antibodies are safe and effective drugs. Moreover, passive immunization with avian antibodies could become an effective alternative therapy, as these can be obtained relatively simply, cost-efficiently, and produced on a large scale. Here, we highlight the potential use of polyclonal avian IgY antibodies as an oral prophylactic treatment for respiratory viral diseases, such as COVID-19, for which no vaccine is yet available.

Argeloside I inhibits the pathogenicity of Porphyromonas gingivalis TDC60

Porphyromonas gingivalis, a major pathogen associated with chronic periodontitis, produces several virulence agents in the outer cell membrane, including gingipains and hemagglutinins. These virulence factors enable the bacteria to adhere to periodontal tissue and degrade host proteins to obtain the nutrients needed for dental plaque formation. P. gingivalis TDC60 was recently identified as the most aggressive P. gingivalis strain to dates. In this study, we isolated a known pregnane glycoside, argeloside I, from the aqueous extract of Solenostemma argel leaves. Argeloside I completely hindered the growth of P. gingivalis TDC60 and inhibited the production of hemagglutinins as well as Arg- and Lys-specific gingipains. Our results demonstrate a new function of pregnane glycosides. Argeloside I may be a candidate for reducing the risk associated with P. gingivalis TDC60 and its adhesion factors.

IgY-technology (egg yolk antibodies) in human medicine: A review of patents and clinical trials

IgY-technology (the production and extraction of specific IgY antibodies from egg yolk) is an innovative method to produce antibodies for therapy and prophylaxis. Advantages of IgY over other antibodies comprise its cost-effective extraction, the minimization of animal harm and distress, and its reduced reactivity with mammalian factors. Many research groups have demonstrated that IgY is active against several pathogens or conditions, a fact that may support the design of novel, safe and effective health products. This review provides a comprehensive analysis of IgY-based biologicals for human medicine, including patent applications and clinical trials during the period 2010-2018, and addresses how IgY-technology can lead to innovation in the production of biologicals for the treatment and prophylaxis of a wide range of infectious and non-communicable diseases.

Isolates from Monechma ciliatum seeds' extract hampered Porphyromonas gingivalis hemagglutinins

Porphyromonas gingivalis is a major periodontitis pathogen that produces several virulence factors including hemagglutinins. These proteins, which are vital molecules, allow P. gingivalis to uptake iron and heme by attaching, aggregating, and lysing erythrocytes. In this study, we evaluated the inhibitory activity of the aqueous extract of Monechma ciliatum seeds against the hemagglutination activity of P. gingivalis. M. ciliatum is a Sudanese medicinal herb that grows in arid and semi-arid lands of tropical Africa. The water extracted from dry powdered seeds was partitioned using ethyl acetate followed by reversed-phase chromatography, thin-layer chromatography, ESI-MS, and NMR analysis resulting in the isolation of four compounds identified as oleic acid, coumarin, 1,2-dioleoylglycerol, and 1,3-dioleoylglycerol with MICs of 15-100 μg/ml against hemagglutination. We believe that the isolation and purification of these compounds will expand the application of M. ciliatum as a natural therapeutic or preventative agent. PRACTICAL APPLICATIONS: Monechma ciliatum or black mahlab is a famous medicinal plant that grows in some parts of arid and semi-arid areas of tropical Africa including western Sudan. Despite its nutritional and traditional medical applications, no studies have evaluated its anti-hemagglutination activity against periodontal pathogens. In this study, four active compounds (oleic acid, coumarin, 1,2-dioleoylglycerol, and 1,3-dioleoylglycerol) were isolated and identified from an aqueous extract of M. ciliatum seeds. The isolated compounds revealed high levels of inhibitory activity against all hemagglutinin agents secreted by Porphyromonas gingivalis. This evidence of inhibitory activity will encourage the application of M. ciliatum effectively as a functional food or therapeutic agent to prevent periodontal diseases in the early stages.

Effects of Passive Immunization by Anti-Gingipain IgY on the Oral Health of Cats Fed Kibble Diets

Porphyromonas gulae is one of the key microorganisms in biofilm dysbiosis that leads to periodontal disease, a prevalent disease in cats. Gingipains are proteases secreted that promote the disruption of cell adhesion and the differentiation of osteoclasts. The use of anti-gingipain immunoglobulin Y (IgY-GP) has emerged as a promising alternative to conventional prevention and treatment methods. The aim of this study was to evaluate the efficacy of IgY-GP on different parameters related to oral health in cats. Twenty adult mixed-breed cats were divided into 2 groups of 10 cats fed with 2 extruded diets differing only by coating. The control group received a coating of 4 g/kg of powdered egg and the test group received a coating of 4 g/kg of IgY-GP. The experiment followed a crossover design with 2 periods, each lasting 40 days with a washout period of 30 days. The evaluated parameters were plaque, calculus, gingivitis index, and percentage of Porphyromonas gingivalis of the oral cavity (%PG-OC) at baseline and after 40 days of diet consumption. All cats remained healthy throughout the study and no adverse reactions or side effects were observed. After 40 days of IgY-GP consumption, the plaque index was significantly lower compared to the baseline ( P = .0133). There were no significant changes in calculus index, gingivitis index, and %PG-OC between groups after 40 days ( P > .05). The consumption of IgY-GP reduces plaque accumulation, which may lead to an improvement in the oral health of adult cats.

Characterization of Chicken-Derived Single Chain Antibody Fragments against Venom of Naja Naja Atra

Traditional, horse-derived antivenin is currently the most efficient treatment against snake bites. However, it is costly and has unpredictable side effects. Thus, alternative, cost-effective strategies for producing antivenin are needed. In this study, we immunized hens with inactivated NNA venom proteins from the cobra Naja naja atra (NNA). Purified yolk IgY antibodies showed specific anti-NNA binding activity comparable to that of the equine-derived antivenin. We used phage display technology to generate two antibody libraries containing 9.0 × 10⁸ and 8.4 × 10⁸ clones with a short or long linker, respectively. The phage ELISA indicated that anti-NNA clones displaying single-chain variable fragments (scFv) were significantly enriched after biopanning. The nucleotide sequences of the light and heavy chain genes of 30 monoclonal scFv antibodies were determined and classified into six groups with the short linker and nine groups with the long linker. These scFv clones specifically bound to NNA proteins but not to venom proteins from other snakes. Their binding affinities were further determined by competitive ELISA. Animal model studies showed that anti-NNA IgY antibodies exhibited complete protective effects, while a combination of scFv antibodies raised the survival rates and times of mice challenged with lethal doses of NNA venom proteins.

IgY antibodies for the immunoprophylaxis and therapy of respiratory infections

Emergence of drug resistance among the causative organisms for respiratory tract infections represents a critical challenge to the global health care community. Further, although vaccination can prevent disease, vaccine development is impeded by several factors. Therefore, novel approaches to treat and manage respiratory infections are urgently needed. Passive immunization represents a possible alternative to meet this need. Immunoglobulin Y antibodies (IgYs) from the yolk of chicken eggs have previously been used against bacterial and viral infections in human and animals. Their advantages include lack of reaction with mammalian Fc receptors, low production cost, and ease of extraction. Compared to mammalian IgGs, they have higher target specificity and greater binding avidity. They also possess remarkable pathogen-neutralizing activity in the respiratory tract and lungs. In this review, we provide an overview of avian IgYs and describe their potential therapeutic applications for the prevention and treatment of respiratory infections.

Evaluation of lozenges containing egg yolk antibody against Porphyromonas gingivalis gingipains as an adjunct to conventional non-surgical therapy in periodontitis patients: A randomized controlled clinical trial

BACKGROUND

In a previous pilot study, one-time application of anti-Porphyromonas gingivalis gingipain egg yolk immunoglobulin (IgY) into scaling and root planing (SRP)-treated periodontal pockets showed profound improvement of clinical and bacteriological parameters in patients with chronic periodontitis. The present study aims to evaluate the efficacy of daily use of lozenges fortified with the antibody as an adjunct to non-surgical therapy in patients with periodontitis.

METHODS

Sixty-four patients with periodontitis were divided randomly into a test and a placebo group. The groups were treated by SRP followed by a daily use of lozenges containing either specific IgY against P. gingivalis gingipains (test) or a sham-immune IgY (placebo). Gingival bleeding index (GBI), probing pocket depth (PD) and quantitation of P. gingivalis in the gingival pockets were assessed at baseline and 8 weeks after the initiation of treatment and compared by using Wilcoxon signed rank test, Mann-Whitney U-test or t test.

RESULTS

Both groups showed significant improvement of all parameters at 8 weeks post treatment (P < 0.001). There was a significant difference in reduction of GBI (P < 0.001) and P. gingivalis cell counts (P < 0.05) in the test group compared with the placebo group. The reduction of PD was greater in the test group compared with the placebo group although there was no statistically significant difference between the two groups.

CONCLUSIONS

The adjunctive use of lozenges containing IgY antibody against gingipains from P. gingivalis resulted in clinical and microbiological benefits in the treatment for chronic periodontitis. Additional investigations are needed to examine if the IgY brings benefits to case patients who do not receive SRP.

Clinical and microbiological effects of egg yolk antibody against Porphyromonas gingivalis as an adjunct in the treatment of moderate to severe chronic periodontitis: a randomized placebo-controlled clinical trial

Purpose

To evaluate the clinical and microbiological effects of the local use of egg yolk immunoglobulin against Porphyromonas gingivalis (anti-P.g. IgY) as an adjunct to scaling and root planing (SRP) in the treatment of moderate to severe chronic periodontitis.

Methods

This was a randomized, placebo-controlled, double-blind trial involving 60 systematically healthy patients with moderate to severe chronic periodontitis. Subjects (n=20/group) were randomly assigned to receive SRP combined with subgingival irrigation of anti-P.g. IgY and anti-P.g. IgY mouthwash, subgingival irrigation of 0.2% chlorhexidine and 0.2% chlorhexidine mouthwash, or subgingival irrigation of placebo and placebo mouthwash for 4 weeks. Probing pocket depth, clinical attachment level, bleeding on probing, and the plaque index were evaluated at baseline and at 4 weeks. Subgingival plaque, gingival crevicular fluid, and saliva were simultaneously collected for microbiological analysis.

Results

Our results showed that anti-P.g. IgY mouthwash was as effective as chlorhexidine at improving clinical parameters over a 4-week period. All the groups showed a significant reduction in levels of P.g. at 4 weeks. No significant difference was observed in the test group when compared to placebo regarding the reduction in the levels of P.g. Anti-P.g. IgY significantly suppressed the numbers of red complex bacteria (RCB) in subgingival plaque and saliva in comparison with placebo. No adverse effects were reported in any of the subjects.

Conclusions

Within the limitations of the study, the present investigation showed that passive immunization with anti-P.g. IgY may prove to be effective in the treatment of chronic periodontitis due to its ability to improve clinical parameters and to reduce RCB. No significant differences were found between the anti-P.g. IgY and placebo groups in the reduction of P.g.

Chicken Egg Yolk Antibodies (IgY) for Prophylaxis and Treatment of Rotavirus Diarrhea in Human and Animal Neonates: A Concise Review

The rotavirus-induced diarrhea of human and animal neonates is a major public health concern worldwide. Until recently, no effective therapy is available to specifically inactivate the rotavirion particles within the gut. Passive immunotherapy by oral administration of chicken egg yolk antibody (IgY) has emerged of late as a fresh alternative strategy to control infectious diseases of the alimentary tract and has been applied in the treatment of diarrhea due to rotavirus infection. The purpose of this concise review is to evaluate evidence on the properties and performance of anti-rotavirus immunoglobulin Y (IgY) for prevention and treatment of rotavirus diarrhea in human and animal neonates. A survey of relevant anti-rotavirus IgY basic studies and clinical trials among neonatal animals (since 1994-2015) and humans (since 1982-2015) have been reviewed and briefly summarized. Our analysis of a number of rotavirus investigations involving animal and human clinical trials revealed that anti-rotavirus IgY significantly reduced the severity of clinical manifestation of diarrhea among IgY-treated subjects relative to a corresponding control or placebo group. The accumulated information as a whole depicts oral IgY to be a safe and efficacious option for treatment of rotavirus diarrhea in neonates. There is however a clear need for more randomized, placebo controlled and double-blind trials with bigger sample size to further solidify and confirm claims of efficacy and safety in controlling diarrhea caused by rotavirus infection especially among human infants with health issues such as low birth weights or compromised immunity in whom it is most needed.

A therapeutic Porphyromonas gingivalis gingipain vaccine induces neutralising IgG1 antibodies that protect against experimental periodontitis

Porphyromonas gingivalis infected mice with an established P. gingivalis-specific inflammatory immune response were protected from developing alveolar bone resorption by therapeutic vaccination with a chimera (KAS2-A1) immunogen targeting the major virulence factors of the bacterium, the gingipain proteinases. Protection was characterised by an antigen-specific IgG1 isotype antibody and Th2 cell response. Adoptive transfer of KAS2-A1-specific IgG1 or IgG2 expressing B cells confirmed that IgG1-mediated protection. Furthermore, parenteral or intraoral administration of KAS2-A1-specific polyclonal antibodies protected against the development of P. gingivalis-induced bone resorption. The KAS2-A1-specific antibodies neutralised the gingipains by inhibiting: proteolytic activity, binding to host cells/proteins and co-aggregation with other periodontal bacteria. Combining key gingipain sequences into a chimera vaccine produced an effective therapeutic intervention that protected against P. gingivalis-induced periodontitis.

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.

Antibodies against Venom of the Snake Deinagkistrodon acutus

Snake venom protein from Deinagkistrodon acutus (DA protein), one of the major venomous species in Taiwan, causes hemorrhagic symptoms that can lead to death. Although horse-derived antivenin is a major treatment, relatively strong and detrimental side effects are seen occasionally. In our study, yolk immunoglobulin (IgY) was purified from eggs, and DA protein was recognized using Western blotting and an enzyme-linked immunosorbent assay (ELISA), similar to therapeutic horse antivenin. The ELISA also indicated that specific IgY antibodies were elicited after the fifth booster, plateaued, and lasted for at least 3 months. To generate monoclonal single-chain variable fragment (scFv) antibodies, we used phage display technology to construct two libraries with short or long linkers, containing 6.24 × 10(8) and 5.28 × 10(8) transformants, respectively. After four rounds of biopanning, the eluted phage titer increased, and the phage-based ELISA indicated that the specific clones were enriched. Nucleotide sequences of 30 individual clones expressing scFv were analyzed and classified into four groups that all specifically recognized the DA venom protein. Furthermore, based on mass spectrometry, the scFv-bound protein was deduced to be snake venom metalloproteinase proteins. Most importantly, both IgY and mixed scFv inhibited the lethal effect in mice injected with the minimum lethal dosage of the DA protein. We suggest that together, these antibodies could be applied to the development of diagnostic agents or treatments for snakebite envenomation in the future.

Extract from Rumex acetosa L. for prophylaxis of periodontitis: inhibition of bacterial in vitro adhesion and of gingipains of Porphyromonas gingivalis by epicatechin-3-O-(4β→8)-epicatechin-3-O-gallate (procyanidin-B2-Di-gallate)

BACKGROUND

The aerial parts of Rumex acetosa L. have been used in traditional European medicine for inflammatory diseases of the mouth epithelial tissue. The following study aimed to investigate the influence of a proanthocyanidin-enriched extract from R. acetosa extract against the adhesion of Porphyromonas gingivalis (P. gingivalis), a pathogen strongly involved in chronic and aggressive periodontitis. A further goal was to define the bioactive lead structures responsible for a potential antiadhesive activity and to characterize the underlying molecular mechanisms of the antiadhesive effects.

METHODOLOGY

An extract of R. acetosa (RA1) with a defined mixture of flavan-3-ols, oligomeric proanthocyanidins and flavonoids, was used. Its impact on P. gingivalis adhesion to KB cells was studied by flow cytometry, confocal laser scanning microscopy and in situ adhesion assay using murine buccal tissue. RA1 and its compounds 1 to 15 were further investigated for additional effects on gingipain activity, hemagglutination and gene expression by RT-PCR.

PRINCIPAL FINDINGS

RA1 (5 to 15 μg/mL) reduced P. gingivalis adhesion in a dose-dependent manner to about 90%. Galloylated proanthocyanidins were confirmed to be responsible for this antiadhesive effect with epicatechin-3-O-gallate-(4β,8)-epicatechin-3'-O-gallate (syn. procyanidin B2-di-gallate) being the lead compound. Ungalloylated flavan-3-ols and oligomeric proanthocyanidins were inactive. RA1 and the galloylated proanthocyanidins strongly interact with the bacterial virulence factor Arg-gingipain, while the corresponding Lys-gingipain was hardly influenced. RA1 inhibited also hemagglutination. In silico docking studies indicated that epicatechin-3-O-gallate-(4β,8)-epicatechin-3'-O-gallate interacts with the active side of Arg-gingipain and hemaglutinin from P. gingivalis; the galloylation of the molecule seems to be responsible for fixation of the ligand to the protein. In conclusion, the proanthocyanidin-enriched extract RA1 and its main active constituent procyanidin B2-di-gallate protect cells from P. gingivalis infection by inhibiting bacterial adhesion to the host cell. RA1 and procyanidin B2-di-gallate appear to be promising candidates for future cytoprotective preparations for oral mouth care products.

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.

Use of Candida-specific chicken egg yolk antibodies to inhibit the adhering of Candida to denture base materials: prevention of denture stomatitis

OBJECTIVES

Polyclonal anti-Candida chicken egg yolk antibodies (anti-IgY) were used to investigate the prevention of adherence of Candida species to denture base material in vitro.

BACKGROUND

Candida is a potential virulence factor that can cause systemic infection and even death in immunocompromised individuals. Because long-term antifungal treatment may lead to the emergence of drug-resistant strains, it is necessary to develop novel preventive measures and treatments for candidiasis.

MATERIALS AND METHODS

Three types of chicken egg yolk antibodies were used in this study: non-specific antibody (control IgY), Candida albicans-specific antibody (anti-C.a.IgY) and Candida glabrata-specific antibody (anti-C.g.IgY). A mixture of different dilutions of each antibody with a suspension of Candida species and denture base material was incubated for 3 h, and then the colony-forming units of Candida on the denture base material were counted.

RESULTS

Compared with control IgY, anti-C.a.IgY and anti-C.g.IgY significantly inhibited the adherence of C. albicans, but anti-C.a.IgY tended to be more potent than anti-C.g.IgY. The adherence of C. glabrata was also inhibited significantly by anti-C.a.IgY and anti-C.g.IgY with almost equivalent potency, indicating that their actions against C. glabrata were comparable.

CONCLUSIONS

This study revealed the inhibitory effects of anti-C.a.IgY and anti-C.g.IgY against the adherence of C. albicans and C. glabrata to denture base material. This finding indicates the possibility of a beneficial effect of IgYs for the prevention of denture stomatitis and candidiasis in clinical settings.

Strategies for the inhibition of gingipains for the potential treatment of periodontitis and associated systemic diseases

Gingipains are the major virulence factors of Porphyromonas gingivalis, the main periodontopathogen. It is expected that inhibition of gingipain activity in vivo could prevent or slow down the progression of adult periodontitis. To date, several classes of gingipain inhibitors have been recognized. These include gingipain N-terminal prodomains, synthetic compounds, inhibitors from natural sources, antibiotics, antiseptics, antibodies, and bacteria. Several synthetic compounds are potent gingipain inhibitors but inhibit a broad spectrum of host proteases and have undesirable side effects. Synthetic compounds with high specificity for gingipains have unknown toxicity effects, making natural inhibitors more promising as therapeutic gingipain blockers. Cranberry and rice extracts interfere with gingipain activity and prevent the growth and biofilm formation of periodontopathogens. Although the ideal gingipain inhibitor has yet to be discovered, gingipain inhibition represents a novel approach to treat and prevent periodontitis. Gingipain inhibitors may also help treat systemic disorders that are associated with periodontitis, including cardiovascular disease, rheumatoid arthritis, aspiration pneumonia, pre-term birth, and low birth weight.

Effects of oral moisturising gel containing egg yolk antibodies against Candida albicans in older people

OBJECTIVE

The aim of this study was to evaluate the inhibitory effects of oral moisturising gel containing egg yolk antibody against Candida albicans (anti-CA IgY) in older people. Therefore, we measured the number of Candia CFU present on oral swabs at baseline and after using the gel.

METHODS

A randomised, double-blind, placebo-controlled trial was conducted among volunteers living in a nursing home in Japan. The participants were divided into two groups. The group 1 participants received oral care using an experimental oral moisturising gel with anti-CA IgY, and those in group 2 received oral care using a placebo oral moisturising gel without anti-CA IgY. The oral care was performed by care workers three times a day for 4 weeks. The participants' tongues were sampled using a swab method at baseline and after 2 and 4 weeks of using the oral gel, and the number of C. albicans, Candida tropicalis and Candida krusei colonies was counted.

RESULTS

The baseline oral condition of the participants in the two groups did not differ significantly. The experimental gel significantly reduced the number of C. albicans colonies from baseline to after 4 weeks of using the oral gel; however, no significant reductions were observed in the number of C. tropicalis or C. krusei colonies.

CONCLUSION

The use of oral moisturising gel containing anti-CA IgY for 1 month significantly reduces the number of C. albicans CFU present on swabs in older people.

Host modulation therapy: An indispensable part of perioceutics

Traditionally, only antimicrobials have been used as the chemotherapeutic modality for the treatment of periodontitis. Though bacteria are the primary etiologic factors of periodontal diseases, yet the extent and severity of tissue destruction seen in periodontitis is determined by the host immuno-inflammatory response to these bacteria. This increasing awareness and knowledge of the host-microbial interaction in periodontal pathogenesis has presented the opportunity for exploring new therapeutic strategies for periodontitis by means of targeting host response via host-modulating agents. This has lead to the emergence of the field of "Perioceutics" i.e. the use of parmacotherapeutic agents including antimicrobial therapy as well as host modulatory therapy for the management of periodontitis. These host-modulating agents used as an adjunct tip the balance between periodontal health and disease progression in the direction of a healing response. In this article the host-modulating role of various systemically and locally delivered perioceutic agents will be reviewed.

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.

Effectiveness of egg yolk antibody against shiga toxin II variant toxicity in vitro and in vivo

We prepared anti-Shiga toxin II variant (Stx2e) and anti-Stx2e B antibodies in chicken egg yolk and investigated their effectiveness in vitro and in vivo. Both Egg yolk antibodies (IgY) reduced the cytotoxic effects of Stx2e to Vero cells. The protective efficacy of anti-Stx2e IgY and anti-Stx2e B IgY was investigated in clean Kunming mice, which were experimentally induced with Stx2e. Peritoneal injection of anti-Stx2e IgY and anti-Stx2e B IgY apparently reduced the lethal effect of Stx2e to mice. These results indicate that both anti-Stx2e IgY and anti-Stx2e B IgY could protect mice from Stx2e challenge. Therefore, anti-Stx2e IgY or anti-Stx2e B IgY might be considered as potential candidate for therapeutics for porcine edema disease.

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.

Biological plaque control: novel therapeutic approach to periodontal disease

Despite its important role in the control of periodontal disease, mechanical plaque control is not properly practiced by most individuals. Therefore, adjunctive chemical plaque control using chlorhexidine and antibiotics has also been suggested as an additional therapeutic strategy to augment mechanical plaque control. However, the additional effects of adjunctive antibiotic therapy are small, and topical chlorhexidine therapy is not without side effects. Given current limitations, new approaches for the control of biofilm are required. The new therapeutic approaches discussed in this review are divided into two categories: probiotics and vaccines. Probiotics is an interesting new field of periodontology research that aims to achieve biological plaque control by eliminating pathogenic bacteria. In addition, passive immunization using egg yolk antibody raised against periodontal pathogens may be an effective approach for the treatment of periodontitis. Further study to evaluate the possible effects of these biological plaque control methods against periodontal disease is warranted.

Slit-Robo: a potential way to treat periodontitis

Slit is a secreted protein known to function through the Roundabout (Robo) receptor. Slit has recently been shown to be an endogenously available inhibitor of leukocyte chemotaxis and as a chemoattractant to recruit vascular endothelial cells to sites for angiogenesis both in vivo and in vitro. The initiation and progression of periodontal diseases, is the result of complex interactions between the colonizing bacteria in the periodontal pockets and host immune and inflammatory responses. Antibiotics such as tetracyclines are commonly used in the management of periodontal infections and yet, have shown modest success in reducing neutrophil-mediated injury. Angiogenesis is important for the maintenance of homeostatus of periodontal tissues. However, few studies have been reported about angiogenesis targeted treatment for periodontitis. Based on its angiogenesis promoting effect and leukocyte chemotaxis inhibition effect, we hypothesize that Slit can be an effective immunotherapeutic agent in the treatment of periodontitis.

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.

In vitro and in vivo effectiveness of egg yolk antibody against Candida albicans (anti-CA IgY)

We prepared anti-Candida albicans antibody in chicken egg yolk (anti-CA IgY) and investigated its in vitro and in vivo effectiveness. Anti-CA IgY significantly reduced the adherence capacity of C. albicans to FaDu cells (human pharynx carcinoma cells) in a dose-dependent manner. The protective efficacy of anti-CA IgY was investigated in experimentally induced oral candidiasis in immunosuppressed mice. Oral administration of anti-CA IgY significantly reduced the number of C. albicans and the scores of the tongue lesions. Moreover, anti-CA IgY reduced the colonization of C. albicans in mice organs. These results indicate that anti-CA IgY has a protective effect against the oral candidiasis of experimentally infected mice and reduces the dissemination of C. albicans. Putting together, these results indicate that anti-CA IgY is effective against C. albicans. This effect might be due to the blocking of the binding of C. albicans to the host cells. Therefore, anti-CA IgY might be considered as a prophylactic immunotherapy or possibly an adjunctive antifungal therapy.