Abstract
Here we report the first experimental validation of the possibility for obtaining immune milk with neutralizing antibodies against SARS-CoV-2 from vaccinated cow and goat using recombinant protein human vaccine, ZF-UZ-VAC2001. In the period of two weeks after first vaccination, we detected the neutralizing antibodies against coronavirus in the blood serum of vaccinated animals. The neutralizing activity, in its peak on the 21st days after receiving the third dose (77th day from first dose), was effective in Neutralization Test using a live SARS-CoV-2 in Vero E6 cells, even after 120-fold serum titration. Colostrum of the first day after 3rd dose vaccinated cow after calving had a greater activity to neutralize the SARS-CoV-2 compared to colostrum of subsequent three days (4.080 µg/ml vs 2.106, 1.960 and 1.126 µg/ml), goat milk (1,486 µg/ml), and cow milk (0.222 µg/ml) in MAGLUMI® SARS-CoV-2 neutralizing antibody competitive chemiluminescence immunoassay. We observed a positive correlation of receptor-binding domain (RBD)-specific IgG antibodies between the serum of actively immunized cow and milk-feeding calf during the entire course of vaccination (r = 0.95, p = 0.027). We showed an optimal regime for immune milk pasteurization at 62.5°C for 30 min, which retained specific neutralizing activity to SARS-CoV-2, potentially useful for passive immunization against coronavirus infection threats.
Competing Interest Statement
The authors declare that the study concept and results are filed for patenting at the Intellectual Property Agency under the Ministry of Justice of the Republic of Uzbekistan with pending application № IAP 2021 0365.
Abbreviations
- ACE2
- angiotensin-converting enzyme 2
- COVID-19
- coronavirus disease
- ELISA
- enzyme-linked immunosorbent assay
- HRP
- horseradish peroxidase
- IgG, IgA, IgM
- immunoglobulin G, A, M
- nAbs
- neutralizing antibodies
- NT
- Neutralization test
- OD
- optical density
- RBD
- receptor-binding domain
- S
- spike protein
- S1
- spike protein receptor-binding subunit
- SARS
- severe acute respiratory syndrome
- VOC
- variants of concern
- CLIA
- chemiluminescence immunoassay
- EUA
- emergency use approval
- ZF-UZ-VAC2001
- Zhifei (ZF) – Uzbekistan (UZ) –Vaccine (VAC) project started in January of 2020 (20/01)