Chicken Egg Yolk-IgY: Passive Immunization Promising Targeted Therapy of COVID-19 Pandemic

The world is threatened by the lethal effects of Coronaviruses (CoVs) that associated with major respiratory disorders. The CoVs are large, enveloped, positive-stranded RNA and therefore, it is considered a complicated virus structure. The spike (S) is the major protein that exists in CoV's structure regulates the viral access to the host using angiotensin-converting enzyme 2 (ACE2) receptor for both severe acute respiratory syndrome Coronaviruses-2 (SARS-CoV-2) and/or SARS-CoV initiates the animal/human disease and elevated immune responses. The receptor binding domain (RBD) in the S-proteins is essential for the CoVs-gene sequences; however the literature discussed CoV S-protein in relation to receptor-binding is little. Therefore, finding a natural antiviral to limit the spreading of CoVs is important. Herein, Immunoglobulin (Ig) Y is considered a kind of passive immunizations, represents 60% of the egg-yolk and can preventing many infectious diseases due to the particularities of IgY-molecule shape functional bioactivity to combat the pathogens. Comparing IgY to other Ig(s) antibodies, it makes the minimal animal stress, produces the lowest responses to mammalian factors. Besides, IgY is the most cost-effective extraction using the precipitation which is efficient protocol produce about (95% purity) of antibodies. We reported that IgY has a killing power to bacterial infections in broilers which beneficial to produce hygienic meat. Also, IgY-technology has a global application for treatment of viral infections and cancers. Interestingly, the anti-SARS CoV-2 single-chain fragments variable (scFv) IgY-antibodies can separate the virus from the host cell ACE2-and RBD-receptors. The expressed scFv-antibody can be assigned to be a specific-antigen binding for the potential neutralization which make a better understanding of the host-cycle range of SARS-CoV2 to adapt the ACE2 for the SARS-CoV-2 infection. Therefore, we concluded in this review that the IgY is promising to be a therapeutic target of a novel Coronaviruses disease-19 (COVID-19) pandemic.