Avian vs mammalian antibodies
Gentian has developed immunoassays using avian antibodies since the start of our development of our Cystatin C Immunoassay in early 2000. Today mammalian immunoglobulin G (IgG) antibodies are the most widely used antibodies in immunoassays, but the interest for avian immunoglobulin Y (IgY) antibodies increases.
Several advantages of avian antibodies over mammalian antibodies are described in the literature. The phylogenetic distance between mammalia and aves ensures that avian antibodies will not react with human rheumatoid factor. Neither will they activate the human complement system. For these reasons, IgY based immunoassays are expected to be associated with less interference from human samples. To highlight, since the human complement system is not activated by the avian antibodies [1], there will be no interference from mammalian antibodies like HAMA or HAAA.
Hansson et al’s publication from 2008 even demonstrates that IgY coated particles give higher signal than particles coated with IgG [2]. IgY coated polystyrene particles seems more colloidal stable compared to its IgG counterpart [3].Several advantages of avian antibodies over mammalian antibodies are described in the literature. The phylogenetic distance between mammalia and aves ensures that avian antibodies will not react with human rheumatoid factor. Neither will they activate the human complement system. For these reasons, IgY based immunoassays are expected to be associated with less interference from human samples.
Hansson et al’s publication from 2008 even demonstrates that IgY coated particles give higher signal than particles coated with IgG [2]. IgY coated polystyrene particles seems more colloidal stable compared to its IgG counterpart [3].
Chicken antibodies production
For antibodies found in eggs, immunoglobulin M (IgM) and A (IgA) are present in the egg white, while IgY is only present in the yolk [4]. IgY is the chicken’s equivalence to the mammalian IgG [5]. Avian antibodies are produced by immunising hens with the specific antigen [6]. The IgY transfers from the serum of the mother hen into the egg yolk [7]. The egg yolk is then separated from the egg white, and the preferred IgY can be isolated by preferred techniques.
Moreover, in the production of avian antibodies, only the egg yolk is collected. As a result, there are no blood collection of animals involved.
Gentian products with avian antibodies
Avian antibodies applied in PETIA
(Particle-Enhanced Turbidimetric Immunoassay)
Phd Tom Nilsen, Product Development Director at Gentian, has used polyclonal antibodies raised in hens immunised with purified calprotectin in his Phd project Avian antibodies applied in particle enhanced turbidimetric immunoassay. Development of serum/plasma calprotectin immunoassay and its clinical performance as a marker for bacterial infections.
The project has established a method for purifying calprotectin antigen from human granulocytes to be used for immunisation of hens to raise antibodies reacting specific to calprotectin and to be used in calibrators and controls.
The prototype assay developed in this PhD project has later been formally developed and launched by Gentian.
References
- Larsson A et al. Chicken antibodies: a tool to avoid interference by complement activation in ELISA. J Immunol Methods. 1992.
- Hansson LO et al. Comparison between chicken and rabbit antibody based particle enhanced cystatin C reagents for immunoturbidimetry. J Immunoassay Immunochem. 2008.
- Dávalos-Pantoja L et al. A comparative study between the adsorption of IgY and IgG on latex particles. J Biomater Sci Polym Ed. 2000.
- Rose ME et al. Immunoglobulin classes in the hen's egg: their segregation in yolk and white. Eur J Immunol. 1974.
- Warr GW et al. IgY: clues to the origins of modern antibodies. Immunol Today. 1995.
- Carlander, D. 2002. “Avian IgY Antibody. In Vitro and In Vivo.” Edited by Larsson. A., Phd, Uppsala University.
- Losch, U. 1996. “How Do the Antibodies Get into the Chicken Egg?” ALTEX 13. http://www.altex.ch/resources/altex_1996_Supp_1_15_17_Loesch.pdf.
