Immunoglobulin Yolk (IgY) Targeting S1, RBD of Spike Glycoprotein and Nucleocapsid of SARS-CoV-2 Blocking RBD-ACE2 Binding Interaction

Coronavirus disease (COVID)-19 caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection has become global pandemic disease causing social and economic chaos. An alternative mitigation method is utilization of specific immunoglobulin (Ig)-Y derived from chicken egg. Our study aimed to evaluate the neutralizing potential of specific IgY targeting S1,RBD of spike glycoprotein and nucleocapsid (N) of SARS-CoV-2 to inhibit receptor-binding-domain (RBD) and angiotensin-converting-enzyme-2 (ACE2) binding interaction. Hy-Line Brown laying hens were immunized with recombinant S1, RBD spike glycoprotein and nucleocapsid (N) of SARS-CoV-2. The presence of spesific S1,RBD,N-IgY in serum and egg yolk were verified by indirect enzyme-linked immunosorbent assay (ELISA). Spesific S1,RBD,N-IgY were purified and characterized from egg yolk by using sodium-dodecyl-sulfate-polyacrylamide-gel-electrophoresis (SDS-PAGE) and evaluated for inhibition of RBD-ACE2 binding interaction in vitro. Spesific IgY were present in serum at 1 week post-initial-immunization (p.i.i), whilst present in egg yolk at 4 weeks p.i.i. Specific S1,RBD,N-IgY in serum were able to inhibit RBD-ACE2 binding interaction starting at 4 until 15 weeks p.i.i. The results of the SDS-PAGE obtained bands at molecular weight of 180 kDa, indicating the presence of whole IgY. Our results showed that S1,RBD,N-IgY were able to inhibit RBD-ACE2 binding interaction in vitro, indicating the potential use of this specific IgY to block virus entry. Our study also demonstrated the proof-of-concept that laying hens were able to produce this specific IgY, which able to block the viral binding and large production of specific IgY, is feasible.