The testing of antibodies raised against poultry red mite antigens in an in vitro feeding assay; preliminary screen for vaccine candidates

Abstract

Dermanyssus gallinae (De Geer), the poultry red mite, is a blood-feeding ectoparasite that infests many bird species. We have used an in vitro feeding assay to allow the identification of protective D. gallinae antigens that may have potential as vaccine candidates. Homogenised mites were extracted sequentially with PBS, Tween 20, Triton X100 and urea giving four protein fractions. Five experimental groups of Lohmann Brown hens were used to generate antibodies; four groups were injected with one of each of the protein fractions in QuilA adjuvant and a control group was injected with adjuvant only. Booster injections were administered 2 and 4 weeks after initial immunisation. Eggs were collected throughout the experiment and soluble IgY antibodies were extracted from a pool of egg yolks collected at week six post-injection. Western blots, performed using post vaccination antibodies from test and control groups, revealed a strong antibody response against a range of injected proteins. Fresh chicken blood, supplemented with antibodies raised against these protein fractions, was fed to mites in an in vitro feeding assay in order to determine whether the antibodies had an anti-mite effect. Although there was variability in the numbers of feeding mites, it was found that the strongest anti-mite effect was seen with the PBS protein fraction, which had a cumulative average mortality of 34.8% 14 days after feeding compared with 27.3% for the control group (P = 0.043).

Assessment of cathepsin D and L-like proteinases of poultry red mite,Dermanyssus gallinae(De Geer), as potential vaccine antigens

“…These data indicate that the miticidal effect of ingested antibodies occurs rapidly, in the first 24 h following ingestion. The rapid effect of ingested antibodies was also observed in mites fed with antirDg-CatD-1 IgY (P F < 0·001) and similarly with other anti-mite antibodies Wright et al 2009). …”

“…It is now recognized that vaccines to bloodfeeding ectoparasites can result in effective and sustainable control (de la Fuente and Kocan, 2003;Willadsen, 2004), including the commercial tick vaccine developed using the protective Bm86 immunogen (Willadsen, 2004). Our previous work Wright et al 2009) along with work published from other research groups (e.g. Harrington et al 2009a,b) has clearly established that vaccination against the poultry red mite, using both native and recombinant antigens, is a feasible objective.…”

“…The in vitro feeding device described by McDevitt et al (2006), as modified by Wright et al (2009), was employed to test the effect of ingested antibodies on mite survival. Briefly, starved, conditioned mites were fed with fresh, heparinized chicken blood (36 USP-units of heparin sodium salt (Sigma) ml − 1 blood) enriched with purified polyclonal chicken IgY (2 mg ml − 1 ) generated against rDg-CatD-1 and rDgCatL-1 or with IgY from a negative control hen (no immunization with recombinant proteins) which was housed in a mite-free environment.…”

Opportunities for integrated pest management to control the poultry red mite, Dermanyssus gallinae

“…Arkle et al (2008) found no significant difference in D. gallinae mortality when fed in vitro on blood from birds immunised with D. gallinae proteins and controls. However, both Wright et al (2009) and Harrington et al (2009a) reported a significant 7.5% or 50.6%, respectively, increase in in vitro mite mortality when fed blood spiked with eggextracted antibodies from D. gallinae immunised birds. However, both authors used different methods of protein extraction; Harrington et al (2009a) used a urea-based method, whilst Wright et al (2009) identified significant mite mortality using PBSextracted proteins but reported no significant effect of urea-extracted D. gallinae proteins on mite mortality.…”

Immune responses of the domestic fowl to Dermanyssus gallinae under laboratory conditions

“…These observations of D. gallinae-infested poultry flocks suggest that infested birds do not develop immunological resistance to D. gallinae, despite prolonged exposure to mites. However, mite-induced immunomodulation is a possibility (Jackson et al 2009) and is observed in other mites such as the northern fowl mite (Ornithonyssus sylviarum) (DeVaney and Ziprin 1980) and such issues are important for vaccine design, especially where vaccination has been proposed as a control measure for D. gallinae (Harrington et al 2009;Wright et al 2009), but there is a lack of understanding of how D. gallinae stimulates and/or modulates host immunity.…”