Results of Pre-Clinical and Clinical Tests of Organic Hydroxyapatite as Adjuvant of Bacterial Vaccine

Abstract

V accination continues to be one of the most effective and safe ways to protect against infectious diseases (Clapp et al., 2011; Clements and Griffiths, 2002). However, the high price of vaccines and their repeated administration throughout the year are serious deterrents to their use in large numbers of animals. Therefore, there is a need to develop new vaccines that have low cost and are used either once or for long periods of time (1-2 years) in order to facilitate the work of both veterinary workers and cattle breeders (Zuhair BI, 2017) Vaccines enhanced with an ad-juvant cause a longer and more intense immune response (Harandi et al., 2009; Peek et al., 2008). The word "adjuvant" comes from the Latin adjuvara, that is, "to help" (He et al., 2000). The adjuvant capacity of minerals was first discovered by Gleny et al. in 1926, after the precipitation of aluminum sulfate suspension of diphtheria toxoid, which increased the immunogenicity of this drug. Later, a large number of inorganic salts were tested, but alum, phosphate, aluminum hydroxide, aluminum hydroxide hydrophosphate and calcium phosphate were only approved. Adjuvants are substances that, in combination research Article Abstract | Vaccination continues to be one of the most effective ways to protect against infectious diseases; therefore, there is a need to develop new vaccines that have low cost and are used either once or for long periods of time.The current study aims to test organic hydroxyapatite in bacterial vaccines on laboratory and farm animals and determine its adjuvant and immunogenic properties. In pre-clinical tests, white mongrel mice weighing 18-20g and rats weighing 250-300g were used. Adjuvant (organic hydroxyapatite) separately and as part of vaccines was administered subcutaneously, intraperitoneally and intramuscularly at a dose of 0.5 ml. Clinical tests of adjuvant were carried out on Holstein-Friesian cows and calves. Experimental vaccines were used: 1) a split-conjugated vaccine against animal brucellosis (as antigens it included the components of brucella (Br. Abortus); 2) a vaccine against mastitis of cows. Results showed that PhA, neutrophils and monocytes in the blood smears of the control group were 1.4 times lower, and twice as much compared to the vaccine without the adjuvant. The maximum PhI(FI) was observed in animals immunized with a split-conjugated vaccine against brucellosis of animals with the adjuvant. The disappearance of vaccine antibody titer in the blood after 30 days was stated, which is positive in the diagnosis of brucellosis. The anti-mastitis vaccine with the adjuvant demonstrates prophylactic properties. In conclusion: Organic hydroxyapatite, obtained from the bones of animals by pyrolysis, displays adjuvant and immunogenic properties when used in bacterial vaccines.