IgY technology: Methods for developing and evaluating avian immunoglobulins for the in vitro detection of biomolecules

Abstract

The term “IgY technology” was introduced in the literature in the mid 1990s to describe a procedure involving immunization of avian species, mainly laying hens and consequent isolation of the polyclonal IgYs from the “immune” egg yolk (thus avoiding bleeding and animal stress). IgYs have been applied to various fields of medicine and biotechnology. The present article will deal with specific aspects of IgY technology, focusing on the currently reported methods for developing, isolating, evaluating and storing polyclonal IgYs. Other topics such as current information on isolation protocols or evaluation of IgYs from different avian species are also discussed. Specific advantages of IgY technology ( e.g. , novel antibody specificities that may emerge via the avian immune system) will also be discussed. Recent in vitro applications of polyclonal egg yolk-derived IgYs to the field of disease diagnosis in human and veterinary medicine through in vitro immunodetection of target biomolecules will be presented. Moreover, ethical aspects associated with animal well-being as well as new promising approaches that are relevant to the original IgY technology ( e.g. , development of monoclonal IgYs and IgY-like antibodies through the phage display technique or in transgenic chickens) and future prospects in the area will also be mentioned.

Preclinical Assessment of IgY Antibodies Against Recombinant SARS-CoV-2 RBD Protein for Prophylaxis and Post-Infection Treatment of COVID-19

“…Another relevant finding concerning costs is that antibody levels were mostly the same regardless of the dose of antigen used when testing from 5 to 50 ug of rRBD ( Figure 2A ). According to previous reports, at doses between 10-100 ug of antigen per individual, adequate levels of specific IgY are obtained, under ELISA assay ( 25 , 55 , 56 ). Moreover, IgY antibody response to doses in the range of 1 to 100 ug of bovine serum albumin was proven to be similar from the sixth week after prime dose ( 57 ).…”

Recent Developments in the Field of Optical Immunosensors Focusing on a Label-Free, White Light Reflectance Spectroscopy-Based Immunosensing Platform

“…Other features of avian IgYs, such as higher molecular weight in comparison with that of their mammalian counterparts (180 kDa vs. 150 kDa), may prove to be advantageous for application to certain types of sensors, e.g., label-free reflectrometric immunosensors, in which the thickness of the analyte–antibody adlayer is of critical importance. Other qualities of avian IgYs, such as high robustness and low cost, as well as avoidance of animal bleeding, which offers better compliance with the “3Rs” ethical principle governing research with animals (Replacement—Reduction—Refinement) [ 68 , 106 ], may help IgYs to become more widely applied as biorecognition molecules in optical immunosensors. Moreover, in accordance with the recommendation of the European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM) [ 107 ], non-animal-derived antibodies might be eventually applied to immunosensors along with other products of synthetic biology, such as aptamers or molecular imprinted polymers [ 108 , 109 ], provided that current problems related to high cost, low availability, and often poor analytical features of the latter can be solved.…”

Mini-review: The market growth of diagnostic and therapeutic monoclonal antibodies – SARS CoV-2 as an example

“…In addition, IgY does not cause allergic reaction for human use because it doesn't cause complement stimulation, so IgY can be used for detection, prevention and treatment of human and animal infection. The in vitro applications of egg yolkderived IgYs to the field of disease diagnosis in human and veterinary medicine through in vitro immunodetection of target biomolecules is highly promising [3]. Moreover, it is reported that IgY is used as a therapeutic agent for neutralization of viral antigens [4].…”