Linhui Wang

Application of chicken egg yolk immunoglobulins in the control of terrestrial and aquatic animal diseases: a review.

Abstract Oral administration of chicken egg yolk immunoglobulin (IgY) has attracted considerable attention as a means of controlling infectious diseases of bacterial and viral origin. Oral administration of IgY possesses many advantages compared with mammalian IgG including cost-effectiveness, convenience and high yield. This review presents an overview of the potential to use IgY immunotherapy for the prevention and treatment of terrestrial and aquatic animal diseases and speculates on the future of IgY technology. Included are a review of the potential application of IgY for the treatment of livestock diseases such as mastitis and diarrhea, poultry diseases such as Salmonella, Campylobacteriosis, infectious bursal disease and Newcastle disease, as well as aquatic diseases like shrimp white spot syndrome virus, Yersina ruckeri and Edwardsiella tarda. Some potential obstacles to the adoption of IgY technology are also discussed.

Evaluation of the efficacy of a bacteriophage in the treatment of pneumonia induced by multidrug resistance Klebsiella pneumoniae in mice.

Multidrug-resistant Klebsiella pneumoniae (MRKP) has steadily grown beyond antibiotic control. However, a bacteriophage is considered to be a potential antibiotic alternative for treating bacterial infections. In this study, a lytic bacteriophage, phage 1513, was isolated using a clinical MRKP isolate KP 1513 as the host and was characterized. It produced a clear plaque with a halo and was classified as Siphoviridae. It had a short latent period of 30 min, a burst size of 264 and could inhibit KP 1513 growth in vitro with a dose-dependent pattern. Intranasal administration of a single dose of 2 × 109 PFU/mouse 2 h after KP 1513 inoculation was able to protect mice against lethal pneumonia. In a sublethal pneumonia model, phage-treated mice exhibited a lower level of K. pneumoniae burden in the lungs as compared to the untreated control. These mice lost less body weight and exhibited lower levels of inflammatory cytokines in their lungs. Lung lesion conditions were obviously improved by phage therapy. Therefore, phage 1513 has a great effect in vitro and in vivo, which has potential to be used as an alternative to an antibiotic treatment of pneumonia that is caused by the multidrug-resistant K. pneumoniae.

Characterization of chicken egg yolk immunoglobulins (IgYs) specific for the most prevalent capsular serotypes of mastitis-causing Staphylococcus aureus

The objective of this in vitro study was to evaluate the potential of egg yolk immunoglobulins (IgYs) for treating mastitis caused by Staphylococcus aureus. Specific IgY against type 5 (IgY-T5), type 8 (IgY-T8) and type 336 (IgY-T336) S. aureus strains were obtained by immunizing hens with whole cell vaccines and the IgY produced were then purified to around 80% purity using a water dilution method coupled with salting out and ultra-filtration. Enzyme-linked immunosorbent assay indicated that the IgY specifically targeted the three homologous strains. A growth inhibition assay was performed in Columbia broth (non-encapsulated form) and phosphate-buffered saline (encapsulated form) for an 8h incubation. The results showed that IgY-T336 significantly inhibited (but only 1.5 log units; P<0.01) the growth of all three strains at 15 mg/ml in the Columbia broth. In contrast, the same concentrations of IgY-T5 and IgY-T8 did not show obvious bacteriostatic activity against the two homologous strains. In phosphate buffered saline, no inhibition of the two encapsulated strains was observed with IgY-T5, IgY-T8 and IgY-T336. However, IgY-T336 reduced live bacteria by 1.0 log unit against strain 336 compared with the control. An internalization test indicated that all of the specific IgY (at 5mg/ml) significantly (about 3.0 log units of the control; P<0.01) blocked the internalization of their homologous strains by bovine mammary epithelial cells (MAC-T cells) within 6h. These results suggested that research on the application of IgY as a treatment for mastitis caused by S. aureus should be focused on the internalization inhibition activity rather than on the growth inhibition activity of the IgY.

Protection of pyrroloquinoline quinone against methylmercury-induced neurotoxicity via reducing oxidative stress.

Pyrroloquinoline quinone (PQQ) is a novel redox cofactor and also exists in various foods. In vivo as well as in vitro experimental studies have shown that PQQ functions as an essential nutrient or antioxidant. Methylmercury (MeHg), as a highly toxic environmental pollutant, could elicit central nervous system (CNS) damage. Considering the antioxidant properties of PQQ, this study was aimed to evaluate the effect of PQQ on MeHg-induced neurotoxicity in the PC12 cells. The results showed that, after pre-treatment of PC12 cells with PQQ prior to MeHg exposure, the MeHg-induced cytotoxicity was significantly attenuated and then the percentage of apoptotic cells and the arrest of S-phase in cell cycle were correspondingly reduced. Moreover, PQQ significantly decreased the production of ROS, suppressed the lipid peroxidation and increased the antioxidant enzyme activities in PC12 cells exposed to MeHg. These observations highlighted the potential of PQQ in offering protection against MeHg-induced neuronal toxicity.

Chitosan–Alginate Microcapsules for Oral Delivery of Egg Yolk Immunoglobulin (IgY): Effects of Chitosan Concentration

In our previous study, chitosan–alginate microcapsules were developed to protect egg yolk immunoglobulin (IgY) from gastric inactivation. The present study was undertaken to determine the effect of chitosan concentration (0–0.8%; w/v) on various properties of the microcapsules in order to produce the optimum chitosan–alginate microcapsules for use in the oral delivery of IgY. The properties investigated included microcapsule morphology, loading capacity for IgY (expressed as the IgY loading percentage, w/w, of microcapsules), encapsulation efficiency (EE%), in vitro gastroresistance, and IgY release. IgY loading percentage and EE% were both highest at 0.2% (w/v) chitosan, and, above this level, further increases were not observed. The stability of IgY in simulated gastric fluid (pH 1.2) was significantly improved by encapsulation in alginate microcapsules (IgY retained 43.5% of its activity) and was further improved by including chitosan at any of the chitosan concentrations assessed (IgY retained an average of 69.4% activity) although there was no difference in protection of gastric inactivation among concentrations of chitosan varying from 0.05% to 0.8% (w/v). Higher chitosan concentrations (i.e., ≥0.2%; w/v) prolonged the release of IgY from the microcapsules during simulated intestinal fluid incubation (pH 6.8). However, above the 0.2% (w/v) level, no significant differences were observed. We conclude that the optimum chitosan concentration for microencapsulation is 0.2% (w/v).

Effectiveness of egg yolk immunoglobulin (IgY) against periodontal disease-causing Fusobacterium nucleatum

To evaluate the in vitro and in vivo effectiveness of egg yolk immunoglobulin (IgY) against periodontal disease‐causing Fusobacterium nucleatum.

Chicken egg yolk immunoglobulin (IgY) developed against fusion protein LTB–STa–STb neutralizes the toxicity of Escherichia coli heat‐stable enterotoxins

To obtain a recombinant enterotoxigenic Escherichia coli (ETEC) fusion enterotoxin protein LTB–STa–STb (Bab) that can express the immunogenicity of the haptens STa and STb and induce their corresponding neutralizing antibodies.