Preparation & preliminary Investigation of Inactivated and Live glycoprotein-E negative Bovine Herpes Virus-1 vaccines

Abstract

In this study we prepared three BoHV-1 vaccines .The viruses used were (BoHV-1 Abu hammad virus strain) and (BoHV-1 gE negative virus strain). We identified the two viruses with IFA and PCR testes and the result was confirmed that the two viruses were positive to every test. then the viruses were propagated on MDBK cells and titerated and The virus titre was 8.5 log10 TCID50/ml in case of Abu-Hammad strain. Meanwhile the titre was 6.5 log10 TCID50/ml for modified BHV-1 gE negative virus. then we made the vaccines from the viruses : 1. Inactivated BoHV-1 Vaccine (Abu-Hammad strain) 2. Live Modified BoHV-1 gE negative Vaccine 3. Inactivated Modified BoHV-1 gE negative Vaccine Then three groups of calves (previously proved to seronegative for the presences of antibodies against BoHV-1 viruses) were vaccinated with these 3 vaccines by injection 2 ml of the vaccine for each calf (contain 105.5TCID50 /ml of the virus) by intramuscular route as first dose then the calves were boostered after 3 weeks from the first dose. Then all calves (vaccinated and control) were bled and serum samples were collected at specific times to measure the immune response of the vaccinated calves against BoHV-1 Abu hammad virus by using SNT and ELISA kits.

The results were that all vaccinated calves developed protective virus neutralizing antibody titres higher than the minimal protective level That mean serum neutralizing (SN) antibody titer was significantly increased to 0.71, 0.76, 0.85 log10 TCID50 in groups I, II, III respectively on 3rd week post vaccination, meanwhile on the 3rd week post booster vaccination the mean serum neutralizing (SN) antibody titer was significantly increased to 1.25 ,1.22 ,1.41 log10 TCID50 in groups I, II, III respectively. By using “CHEKIT-Trachitest Serum Screening ELISA Test Kit” for measure the humoral immune response of the calves the results were that the mean ELISA percent increased to 229.67, 114.87, 218.00 % in groups I, II, III on the 3rd week post vaccination respectively. But on the 3rd week post booster vaccination the mean ELISA percent increased to 304.43, 272.70 and 302.13% in groups I, II, III respectively. BoHV-1 gE Antibody ELISA kit was used to detect antibody against gE and the results were that groups vaccinated with gE-negative BoHV-1 vaccines didn’t produce antibodies against gE but these antibodies were detectable within the 1st week of vaccination with abu hammad strain and extend along the period of experiment. Also nasal swabs were collected from groups vaccinated with gE-negative BoHV-1 vaccines on 1st,2nd,3rd and 4th weeks post vaccination weeks post booster vaccination for insure of virus shedding in nasal swabs of the vaccinated calves also IFAT and PCR tests were applied on the swabs and the results were negative for all testes.