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

Abstract

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.

Keywords: IgY; Staphylococcus aureus; adjuvant; atopic dermatitis; λ-carrageenan.

Fig. 1.

Structures of (A) κ-, (B) ι-, and λ-carrageenan (C).

Fig. 2.

Changes in anti-S. aureus IgY activity in Egg Yolk. The changes of IgY activity in diluted egg yolk by ELISA of three individual hens are shown as -×-, -■- and -▲- in each group. The arrows indicate the times of immunization. FIA: Freund's incomplete adjuvant, FCA: Freund's complete adjuvant, λCarra: λ-carrageenan. The bar () indicates the period in which hen egg yolk was pooled (-×-) and used for IgY purification.

Fig. 3.

Reactivity of each purified IgY with S. aureus (by ELISA). Data represent means±SD (n=3).

Fig. 4.

Changes in S. aureus growth monitored by turbidity (A) and ATP luminescence activity (B). The amount of S. aureus incubated with each individual IgY was measured by turbidity and luminescence ATP activity. Data represent mean±SD (n=3). Different letters indicate statistically significant differences.