Role of stabilizers in preparation of a potent sheep pox vaccine

Production of live attenuated sheep pox vaccine sustained the elevated temperatures during freeze-drying, transportation storage and vaccination in unequipped tropical and subtropical zones of the world, is highly recommended. For this reason, eight stabilizer formulas were individually used for preparation of eight sheep pox vaccines, which were lyophilized and then titrated and accordingly four vaccine formulas were eventually selected that should be tested for thermoprotectivity to select the best stabilized vaccine. These selected vaccines were tested for sterility; potency [vaccination and challenge] and safety in susceptible sheep. The collected blood sera were subject to serological examination for estimating the antibody response by ELISA. The results proved transcendence of sheep pox vaccines stabilized with 10% trehalose alone or in combination with 5% lactalbumin hydrolyste in the thermoprotectivey, thereby improvement vaccination efficacy

Protective immunity induced by co-injection of mixture of Mannan and B-glucan immunostimulant substances with the inactivated Bivalent Al-ND vaccine in broiler chickens

In the present study, the effect of a mixture of some immunostimulant substances on the immune response of broiler chicks to bivalent Al-ND vaccine was determined. Four groups of chicks were used. Group .1 was vaccinated with one dose of Al-ND vaccine and simultaneously injected with the mixture of immunostimulant substances. Group 2 was vaccinated with one dose of the bivalent AI.-ND vaccine. Group 3 was vaccinated with 2 doses of live ND vaccines [Hitchner then Lasota drains] and group 4 was kept none vaccinated control chicb. All birds were monitored weekly for the humoral and cellular immune response then challenged with the virulent NDV at 35 days of age. HI test was used for titration of antibodies for both AIV and NDV, phagocytic activity, Nitric oxide; Lysozyme activity and total antioxidant in serum were used to determine the cellular immune response of the chicks. Protective immunity induced in the vaccinated groups varied. The injected immunostimulant mixture demonstrates its effect on the immune response to the bivalent Al-ND vaccine in group 1 with 100% protection against the challenge NDV. Whereas, 80 and 60% protection were obtained in chicks vaccinated either. with Al-ND vaccine [group 2] or live ND vaccines [group 3]; respectively. The present study reports the effect of injection of some immunostimulant substances in augmentation of the immune response to the inactivated vaccines

Construction of a recombinant baculovirus expressing the major capsid protein [VP6] of bovine rotavirus

The present study reports the expression of VP6, the major inner capsid protein of bovine rotavirus Nebraska calf diarrhea virus [NCDV] strain in a baculovirus expression system. The full-length DNA copies of RNA segment 6 [coding for VP6 protein] of NCDV were inserted into a baculovirus expression vector. A recombinant baculovirus carrying the VP6 gene was constructed through homologous recombination between the baculovirus recombinant plasmid carrying the VP6 gene and Autographa californica nuclear polyhedrosis virus [AcNPV] under the control of the polyhedrin promotor. Infection of Spodoptera frugiperda [Sf9] cells with the recombinant baculovirus expressing VP6 protein revealed a high-level of expression when tested by immunoflurescence and solid phase ELISA tests using BRV-specific polyclonal antibodies. The VP6 expressed protein was detected in Coomassie blue stained SDS-PAGE and produced a detectable band in Western blot assay. The high degree of reactivity with BRV-specific polyclonal antibodies confirmed that the antigenic determinants of the expressed protein were unaltered. The use of the in vitro expressed VP6 protein in the field diagnosis and vaccine development to control rotavirus infection is of considerable intere

Expression of the bovine coronavirus spike glycoprotein subunits in insect cells using recombinant baculoviruses

In the present study, the bovine coronavirus [BCV] spike glycoprotein cleavage products [S1 and S2] were individually expressed in Spodoptera frugiperda [Sf9] insect cells, using a baculovirus expression system. The coding sequence of S1 and S2 gene fragments were amplified by RT-PCR and cloned into the baculovirus shuttle vector pBlueBac4.5/V5-His TOPO [R] TA. The cloned fragments were inserted into the genome of Autographa californica nuclear polyhydrosis virus [AcMNPV] under control of the polyhedrin promoter, through a process of homologous recombination between the shuttle vector and a linearized replication-defective baculovirus DNA [Bac-N-Blue[TM]]. Recombinant baculoviruses were selected by plaque purification; verified for the presence of target sequences using PCR and propagated for generation of high-titer viral stocks. Infection of insect cells with the recombinant baculoviruses revealed high-level expression of the target proteins as indicated by immunofluoresent test and solid phase ELISA using BCV-specific polyclonal antiserum

Growth curve of BVD viral infectivity and antigens as measured by some recent techniques

The present study deals with the growth behaviour of BVD [Singer strain] virus in primary BK cells with regard to the rate of virus increase in cell free and cell associated virus, as well as detection of viral protein as assayed by Dot-ELISA, FAT and IPT. The results revealed the following: The optimum time to harvest the cell free virus was at 72 hours PI with titer [10[4.6]] while for cell associated virus part its peak [10[4]] was at 48 hours PI.The maximal development of viral antigens could be traced and titrated by Dot-ELISA. The most extensive reactions had been given by the cell free viral antigen 72 hours, its titer was found to be higher [2[6]] than the intracellular [2[5]] virus harvest 48 hours PI.The FAT proved to be sensitive and reliable technique for detecting and tracing the development of viral antigens. The best time to detect clear intracytoplasmic fluorescence in BK cells was at 48 hours PI.Regarding the comparative sequential studies between IPT and FAT it was found that both tests ran parallel concerning their sensitivity for detection and tracing of BVD viral antigens

Validity of SPA in quantal assay of antibodies to BVD virus in field serum samples

76 bovine serum samples were collected from different farms and tested for the presence of antibodies to BVD virus. For this purpose, the SPA-agllutination test has been introduced as a new approach in comparison with the serum neutralization test [SNT] and the immunodiffusion [ID] technique. Therefore, the samples have been categorized in four groups according to their titers in the SNI: 1st group included positive sera with high antibody titer [32 to 64]; 2nd group included positive sera with medium antibody titer [8 to 16]; 3rd group contained cytotoxic samples and the 4th group comprised all negative samples. The obtained data could prove that the SPA test as a binding assay is relatively more sensitive than the SNT in detecting antibodies to BBVD virus giving end titers ranged from 16 to 128. The SPA test could also detect anti-BVD antibodies in cytotoxic serum samples. Although the ID test is a simple technique for detection of antibodies yet it was of relative lower sensitivity than the SNT and SPA agglutination tests, and showed itself in this work non-suitable for screening of antibodies to BVD virus