Molecular and immunogenic characterization of BHK-21 cell line adapted CVS-11 strain of rabies virus and future prospect in vaccination strategy

Abstract

Development of a cost effective quality vaccine is a key issue in rabies control programme in developing countries. With this perspective, in the present study, challenge virus standard (CVS)-11 strain of rabies virus was adapted to grow in BHK-21 cells, characterized, compared with other viruses including global vaccine strains and field isolates from Indian subcontinent and China at molecular level. This cell adapted virus was evaluated for the production of cost effective veterinary vaccine. The maximum virus titre achieved was 10 7 fluorescent focus unit (FFU)/mL at 10th passage level. There was no nucleotide difference in the nucleoprotein (N) and glycoprotein (G) genes after adaptation in cell line. Phylogenetic analysis showed that adapted virus was grouped with global vaccine strains, closest being with other CVS strains but distinct from the Indian field isolates. Global vaccine strains including cell adapted CVS-11 virus have 83-87 % identity at nucleotide level of G gene with Indian field viruses. Growth kinetics of cell culture adapted virus showed that the optimum virus titer (around 10 7 FFU/mL) could be obtained at around 48 h post infection by cocultivation method using 0.1 multiplicity of infection inoculums at 37°C. These findings can be used for up scaling of vaccine production. The protective efficacy of test vaccine produced using 10 6.95 FFU/mL cell culture harvest showed 1.17 IU/mL relative potency by NIH test. Further, adapted virus was found to be suitable for use in rapid fluorescent focus inhibition test.

Protective antibody response of Balb/c mice to Bali rabies virus isolate propagated in BHK-21 cells

“…1B ), without an observable CPE. The result was similar to the previous finding that RABV infections can persist for prolonged periods in cell cultures without causing an observable CPE [ 22 ]. The use of simple and rapid detection methods such as IIFA and ICC is important to detect RABV infection in BHK-21 cells following inoculation with the Bali RABV isolate ( Fig.…”

“…Generally, RABV replicates in many cell lines including BHK-21 and Vero cells [ 7 , 21 , 22 , 31 ], without producing any observable cytopathic effect (CPE) [ 22 ]. The replication of the virus in many types of cell cultures has enabled the mass production of RABV for use in the preparation of antigens for diagnostic and vaccine purposes.…”

Generation of a recombinant rabies virus expressing green fluorescent protein for a virus neutralization antibody assay

“…The conventional FAVN method uses CVS-11 as the standard RABV [ 7 ]. CVS-11 was adapted in mice, is recommended for use in FAVN method, and is used worldwide as a challenge virus [ 21 ]. In this study, 4-week-old mice were inoculated intracranially with a high titer of ERAGS-GFP, which was safe for 16 days and did not cause loss of body weight in mice.…”

Effect of mineral supplementation on humoral immunity against rabies vaccine in dog pups

“…After the virus neutralization, 32 µL of BHK-21 cells was added in all wells and incubated at 37ºC for 24 hrs in humidified chamber at 5% CO 2 tension. Cell monolayer was washed with PBS and fixed with 80% chilled acetone (80/ 20 in PBS) and stained with rabies anti-nucleocapsid FITC (Fluorescein isothiocyanate) conjugate (Patel et al 2015). Antibody titre in both the groups was calculated and compared.…”