Intravenous anti-P. aeruginosa IgY-antibodies do not decrease pulmonary bacterial concentrations in a porcine model of ventilator-associated pneumonia.

Ventilator associated pneumonia (VAP) caused by P. aeruginosa is a cause of morbidity and mortality in critically ill patients. The spread of pathogens with anti-microbial resistance mandates the investigation of novel therapies. Specific polyclonal anti-P. aeruginosa IgY-antibodies (Pa-IgY) might be effective for VAP caused by P. aeruginosa. The objective of this study was to investigate if intravenous Pa-IgY decreases the lower airway concentration of P. aeruginosa in VAP. We used a double blind randomized placebo controlled porcine model of VAP caused by P. aeruginosa. Eighteen pigs were randomized to either receive intravenous Pa-IgY or placebo. Repeated registration of physiological parameters and sampling was performed for 27 h. Concentration of P. aeruginosa in BAL-cultures was similar in both groups with 104.97 ± 102.09 CFU/mL in the intervention group vs 104.37 ± 102.62 CFU/mL in the control group at the end of the experiment. The intervention group had higher heart rate, cardiac index, oxygen delivery and arterial oxygen tension/fraction of inspired oxygen-ratio, but lower plasma lactate and blood hemoglobin levels than the control group. In summary, in an anesthetized and mechanically ventilated porcine model of VAP, Pa-IgY at the dose used did not decrease concentrations of P. aeruginosa in the lower airways.

Correction to: Inhalation of specific anti-Pseudomonas aeruginosa IgY antibodies transiently decreases P. aeruginosa colonization of the airway in mechanically ventilated piglets.

Following publication of the original article [1], the authors flagged that an incorrect piece of data is given in the Materials and Methods section of the article.

Inhalation of specific anti-Pseudomonas aeruginosa IgY antibodies transiently decreases P. aeruginosa colonization of the airway in mechanically ventilated piglets.

BACKGROUND: P. aeruginosa is a pathogen frequently resistant to antibiotics and a common cause of ventilator-associated pneumonia (VAP). Non-antibiotic strategies to prevent or treat VAP are therefore of major interest. Specific polyclonal avian IgY antibodies have previously been shown to be effective against pneumonia caused by P. aeruginosa in rodents and against P. aeruginosa airway colonization in patients. OBJECTIVES: To study the effect of specific polyclonal anti-P. aeruginosa IgY antibodies (Pa-IgY) on colonization of the airways in a porcine model. METHOD: The pigs were anesthetized, mechanically ventilated, and subject to invasive hemodynamic monitoring and allocated to either receive 109 CFU nebulized P. aeruginosa (control, n = 6) or 109 CFU nebulized P. aeruginosa + 200 mg Pa-IgY antibodies (intervention, n = 6). Physiological measurement, blood samples, and tracheal cultures were then secured regularly for 27 h, after which the pigs were sacrificed and lung biopsies were cultured. RESULTS: After nebulization, tracheal growth of P. aeruginosa increased in both groups during the experiment, but with lower growth in the Pa-IgY-treated group during the experiment (p = 0.02). Tracheal growth was 4.6 × 103 (9.1 × 102-3.1 × 104) vs. 4.8 × 104 (7.5 × 103-1.4 × 105) CFU/mL in the intervention group vs. the control group at 1 h and 5.0 × 100 (0.0 × 100-3.8 × 102) vs. 3.3 × 104 (8.0 × 103-1.4 × 105) CFU/mL at 12 h in the same groups. During this time, growth in the intervention vs. control group was one to two orders of ten lower. After 12 h, the treatment effect disappeared and bacterial growth increased in both groups. The intervention group had lower body temperature and cardiac index and higher static compliance compared to the control group. CONCLUSION: In this porcine model, Pa-IgY antibodies lessen bacterial colonization of the airways.

IgY stability in eggs stored at room temperature or at +4°C.

1. The aim of this study was to investigate the stability of immunoglobulin-Y (IgY) in stored eggs from immunised hens. 2. Eggs from individual hens were randomised and stored for up to one month at room temperature, or for up to 6 months at +4°C. IgY was extracted from the egg yolks and the antibody activities were tested by ELISA. 3. There was no significant reduction in antibody titres with egg storage under these conditions. 4. Egg yolks of immunised chickens provide an inexpensive source of large amounts of polyclonal antibodies for use in immunotherapy and immunoassays. By collecting eggs from different immunised hens and pooling their yolks, it should be possible to reduce batch-to-batch variation.

Alkylaminopropenones and alkylamino-propenoates as efficient and versatile synthons in microwave-assisted combinatorial synthesis.

A simple and fast one-pot method using microwave irradiation for the synthesis of a number of small libraries of diverse heterocycles is described in this paper. The two-step one-pot method includes the formation of alkylaminopropenones or alkylaminopropenoates in 5 min at 180 degrees C and a subsequent treatment with dinucleophiles for 3 to 5 min at 150 degrees C to 180 degrees C to form a variety of biologically interesting heterocycles in a cascade-type reaction. The combination of combinatorial chemistry and microwave-assisted synthesis was found to be very efficient.

Extraction of IgY from egg yolk using a novel aqueous two-phase system and comparison with other extraction methods.

Egg yolk is an important source of antibodies. The biggest obstacle for isolation of chicken antibodies (IgY) is the removal of lipids, which are present in abundance in egg yolk. We have used a two-phase system to separate egg yolk. The use of an aqueous two-phase system with phosphate and Triton X-100 made separation of lipids and water-soluble proteins possible. Lipids are extracted into the detergent-enriched top-phase, whereas IgY is isolated in the phosphate-enriched bottom-phase. The phosphate:triton system was characterised and optimised using various experimental designs. For the optimised model, the yield of IgY was kept above 97% (11.1-14.9 mg IgY/g egg yolk recovered). The amount of lipids in the bottom-phase was kept below 25% of the total content in the egg yolk added. Hence, the model described provides a method for extracting the IgY-fraction with a high yield and relatively low lipid content.

Chicken antibodies: a clinical chemistry perspective.

The chicken immune system has been studied for many years and these studies have contributed substantially to our understanding of the fundamental concepts of immunology and the development of different immunoglobulin classes. It is thus surprising that only a small fraction of the antibodies presently used in laboratories are of avian origin. A laying hen produces more yolk antibodies than a rabbit can produce during the same time period, and the animal care costs are lower for the chicken compared to the rabbit. Chicken antibodies offer many advantages to the traditional mammalian antibodies when used for the detection of mammalian antigen. Due to the evolutionary difference chicken IgY will react with more epitopes on a mammalian antigen, which will give an amplification of the signal. Chicken antibodies can also be used to avoid interference in immunological assays caused by the human complement system, rheumatoid factors, human anti-mouse IgG antibodies (HAMA) or human and bacterial Fc-receptors. The antibodies can be purified in large amounts from egg yolk, making laying hens highly efficient producers of polyclonal antibodies.