Ovine rotavirus strain LLR-85-based bovine rotavirus candidate vaccines: Construction, characterization and immunogenicity evaluation

Abstract

Group A bovine rotaviruses (BRVs) are the most important cause of diarrheal diseases in neonatal calves and cause significant morbidity and mortality in the young animals, and epidemiologic surveillance of bovine rotavirus G genotypes conducted in various cattle populations throughout the world has shown that approximately 90% of the bovine rotavirus isolates belong to G6 and G10. Based on the modified Jennerian approach to immunization, we constructed and characterized a reassortant rotavirus stain, which bears a single bovine rotavirus VP7 gene encoding G genotype 6 specificity while the remaining 10 genes are derived from the ovine attenuated rotavirus LLR-85. The reassortant rotavirus strain, named as R191, and its parental virus strain LLR-85 were combined as bivalent vaccine candidates to inoculate the colostrums-deprived neonatal calves for evaluation of the immunogenicity. The calves were orally inoculated with the reassortant R191 (group 1), the parental rotavirus LLR-85 (group 2), or combined the R191 and LLR-85 (group 3), and serum specimens were detected to determine the immune response of IgG and IgA antibodies. Results showed that seroconversion to positivity for IgG and IgA antibodies occurred at postinoculation day (PID) 10 in all of the inoculated calves, and the highest titers of the serum IgG (range 1:800 to 1:6400) and IgA (range 1:800 to 1:3200) antibodies were obtained at PID 21 for all calves. Meanwhile, virus shedding was detected after inoculation, showing that the inoculated virus was positive in 2 of 77 fecal specimens (2.6%) collected from the inoculated calves during the first 7 days of oral inoculation with the rotavirus vaccine candidates. The results suggested that the rotavirus strains R191 and LLR-85 are promising bivalent vaccine candidates for the prevention of bovine G6 and G10 rotavirus infection.

Molecular Characterization of Bovine Rotaviruses in Pakistan

“…For the confirmation of bovine rotavirus, amplification of both the VP4 and VP6 gene was carried out using primer sets given in Table 1 as mentioned in (4,16,17). For the desired amplification of VP4 gene (880 bp) and VP6 gene (250 bp) of bovine rotavirus, optimization of PCR conditions was done by using the varying concentrations of cDNA, primers and Taq polymerase in PCR reaction mixture.…”

“…The genome is a double stranded RNA having 11 segments, which encodes six structural viral proteins (VP1-4, VP6, and VP7) and six non-structural proteins (NSP1-6) (2, 3). The structural viral proteins VP4, VP6 and VP7 are important as they are used for serological characterization of rotaviruses (4). In reference to the immunity development, VP4 and VP7 are helpful, so information of these genotypes is necessary to develop a vaccine (5).…”

Inhibition of Rotavirus Infectivity by a Neoglycolipid Receptor Mimetic

“…Although it is too early to know whether and to what extent the widespread use of HRV will lead to immune selection of new strains, there is the potential for vaccine-associated collateral infections especially in immunocompromised individuals [ 10 ]. In contrast to attenuated-live vaccines, the use of inactivated or non-replicative virus like particles (VLPs) as vaccine candidates, coupled with new strategies for boosting mucosal immunity, [ 9 , 11 , 12 , 13 , 14 ], and/or direct competition with virus-host cell binding using a dietary nutriceutical approach, may have the greatest potential to provide stable, long-term protection against rotavirus disease in both animals and people. This approach also reduces the possibility of emergence of virus P and G types not represented in the vaccine strains since non-replicative virus particles will not reassort with wild type rotaviruses.…”

“…Despite remarkable progress in rotavirus vaccine development for both animals [ 12 , 13 , 15 , 16 , 17 ] and humans [ 2 , 18 , 19 , 20 , 21 , 22 ], there are no effective commercial vaccines or licensed rotavirus-specific antiviral agents for animals in wide clinical use and no practical method of preventing rotavirus infection in swine herds. In this report, we provide proof of concept that an orally administered, synthetic, neoglycolipid can be used as a therapeutic receptor mimetic for the prevention of Group A rotavirus disease in neonatal piglets.…”