Prospects for developing an intranasal vaccine against respiratory diseases of newborn calves

Respiratory diseases of young animals remain an economically significant problem to this day, causing great damage to cattle breeding in our country. Infectious rhinotracheitis virus (IRV), parainfluenza-3 (PI-3), respiratory syncytial virus (RSV) are recognized as dominant in the development of this pathology, and therefore, developing a vaccine against them is very relevant. Abroad, intranasal vaccination of newborn calves in the first days of life is recognized as economically advantageous, convenient, and labor-saving for specific prevention of infectious diseases caused by these viruses. The feasibility of development is also based on the absence of such a vaccine in the Russian Federation. Live vaccines, regardless of the presence and quantity of circulating antibodies in the blood, unlike inactivated ones, allow for a short period of time to obtain stable, long-term immunity to the disease. In this regard, the development of live highly specific vaccines from attenuated strains of respiratory pathogens is a very urgent task of modern biotechnology. At the first stage, virus strains were selected to create a vaccine, and their infectious, hemagglutinating and hemadsorbing titers were assessed. It was shown that the transplantable line of bovine embryonic lung cell culture (LEC) is permissive for candidate strains. Infectious titers of the strains TK-A(VIEV)-B2 of the IBR virus of bovine, PTK-45/86 of the PG-3 virus of bovine, VR-1339 and Lym-56 of the RSV of bovine were 6.17±0.09, 5.67±0.10, 4.42±0.18 and 4.50±0.18 lg TCID50/cm3, respectively. The titer of PTK-45/86 of the virus in terms of hemadsorption capacity corresponded to 5.33±0.10 lg, in the RGA - 53.33±13.06. High titers of candidate strains indicate the possibility of their use in the development of a technology for the production of a live attenuated import-substituting vaccine against IRT, PG-3, RSI for the prevention of respiratory infections in young animals by intranasal immunization of calves from the first days of life.