Novel preparation technique of hyperimmune globulins against bovine coronavirus as surrogate of beta coronavirus

Abstract

Consuming time and effort to prepare hyperimmune globulins using Freund’s adjuvant is a sophisticated and harsh technique. In this work, a novel, safe, and rabid method was proposed using monolaurin as an immune-stimulating agent in hyperimmune globulins production against Bovine coronavirus (BCoV). The mentioned virus was used as a surrogate to family Betacoronavirus. Bovine coronavirus (Mabus strain) with titer log10 5.8 tissue culture infective dose infectivity (TCID50)/ml was used in this experiment. The inactivation of the virus was done using 1% ascorbic acid for 24h. Monolaurin emulsion (10% w/v) of was prepared by sonication using tween 20 and water. The inactivated bovine coronavirus was added to the emulsion by 20% of the final volume. The immunoglobulins were prepared by inoculating the inactivated virus with the adjuvant in rabbits and evaluated on the Madin-Darby bovine kidney (MDBK) cell line by virus neutralization test (VNT). The effect of the adjuvant was assessed by histopathological examination of vital organs such as the kidney and liver. The antibody titer against the BCoV was reached its peak, log2 1024 TCID50/ml, at the 3rd-week post-inoculation in the rabbits. The level of the globulin reached a high level and its peak (14.3g/dL) at the end of the experiment. No abnormalities were seen in the livers and kidneys of the negative control group of rabbits. Monolaurin showed a new level of safety and efficacy when used as an adjuvant during the preparation of the immunoglobulins against BCoV.