Hyperimmunized Chickens Produce Neutralizing Antibodies against SARS-CoV-2.

The novel severe acute respiratory syndrome (SARS) coronavirus, SARS-CoV-2, is responsible for the global COVID-19 pandemic. Effective interventions are urgently needed to mitigate the effects of COVID-19 and likely require multiple strategies. Egg-extracted antibody therapies are a low-cost and scalable strategy to protect at-risk individuals from SARS-CoV-2 infection. Commercial laying hens were hyperimmunized against the SARS-CoV-2 S1 protein using three different S1 recombinant proteins and three different doses. Sera and egg yolk were collected at three and six weeks after the second immunization for enzyme-linked immunosorbent assay and plaque-reduction neutralization assay to determine antigen-specific antibody titers and neutralizing antibody titers, respectively. In this study we demonstrate that hens hyperimmunized against the SARS-CoV-2 recombinant S1 and receptor binding domain (RBD) proteins produced neutralizing antibodies against SARS-CoV-2. We further demonstrate that antibody production was dependent on the dose and type of antigen administered. Our data suggests that antibodies purified from the egg yolk of hyperimmunized hens can be used as immunoprophylaxis in humans at risk of exposure to SARS-CoV-2.

Egg yolk immunoglobulin (IgY) targeting SARS-CoV-2 S1 as potential virus entry blocker.

AIMS: COVID-19 pandemic caused by SARS-CoV-2 has become a public health crisis worldwide. In this study, we aimed at demonstrating the neutralizing potential of the IgY produced after immunizing chicken with a recombinant SARS-CoV-2 spike protein S1 subunit. METHODS AND RESULTS: E. coli BL21 carrying plasmid pET28a-S1 was induced with IPTG for the expression of SARS-CoV-2 S1 protein. The recombinant His-tagged S1 was purified and verified by SDS-PAGE, Western blot and biolayer interferometry (BLI) assay. Then S1 protein emulsified with Freund's adjuvant was used to immunize layer chickens. Specific IgY against S1 (S1-IgY) produced from egg yolks of these chickens exhibited a high titer (1:25,600) and a strong binding affinity to S1 (KD  = 318 nmol L-1 ). The neutralizing ability of S1-IgY was quantified by a SARS-CoV-2 pseudotyped virus-based neutralization assay with an IC50  value of 0.99 mg ml-1 . In addition, S1-IgY exhibited a strong ability in blocking the binding of SARS-CoV-2 S1 to hACE2, and it could partially compete with hACE2 for the binding sites on S1 by BLI assays. CONCLUSIONS: We demonstrated here that after immunization of chickens with our recombinant S1 protein, IgY neutralizing antibodies were generated against the SARS-CoV-2 spike protein S1 subunit; therefore, showing the potential use of IgY to block the entry of this virus. SIGNIFICANCE AND IMPACT OF THE STUDY: IgY targeting S1 subunit of SARS-CoV-2 could be a promising candidate for pre- and post-exposure prophylaxis or treatment of COVID-19. Administration of IgY-based oral preparation, oral or nasal spray may have profound implications for blocking SARS-CoV-2.

Chicken IgY Antibodies Provide Mucosal Barrier against SARS-CoV-2 Virus and Other Pathogens.

BACKGROUND: This mini review includes two case descriptions. It introduces the use of chicken egg yolk antibody (IgY) solutions in the prevention and cure of viral and bacterial infections. Application for the protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), rotavirus, and influenza viruses, as well as for the eradication of Pseudomonas aeruginosa, caries, various enteric bacteria and other pathogens, and toxins have been developed. This approach is a fast, reliable, safe, and tested method for producing molecular shield and protection against emerging pathogens and epidemics. In the current pandemic situation caused by coronavirus disease-2019 (COVID-19), this method of passive immunization could be applied for rapid protection against modifiable agents. The specific IgY antibodies start to accumulate into egg yolks about 3 weeks after the immunization of the chicken. The product can be collected safely, as the antigen is not found in the eggs. This method for microbial safety uses natural means and commonly used food substances, which have been tested and could be produced for both blocking epidemics and applying personalized medicine.