Abstract:

Senecavirus A (SVA) has the ability to form intact virions and empty capsids during replication; however, the conditions for isolating them and their differences in antibody response are still unknown. In this study, we utilized guanidine hydrochloride to generate SVA empty capsids and determined the optimal conditions for separating SVA intact virions and empty capsids. This was achieved through ultracentrifugation using different density gradients, media, rotation rates, and durations. Subsequently, SVA intact virions and empty capsids were intramuscularly immunized into BALB/c mice at a dosage of 12.5 μg per mouse. Specific and neutralizing antibodies were then monitored 1-7 weeks post-immunization. The findings indicated that the addition of 100 mmol·L^-1 guanidine HCl for 2 hours in infected cells at MOI=1 of SVA resulted in the complete formation of empty capsids. The most effective method for distinguishing SVA intact virions from empty capsids was centrifugation at 36 000 r·min^-1 for 2.5 hours, using a cesium chloride gradient ranging from 10% to 50%. Furthermore, the specific and neutralizing antibody levels for SVA intact virions were comparable to those of empty capsids. This study provides a new reference for the isolation and purification of the complete and empty capsid of Seneca virus A, as well as for the development of recombinant SVA virus-like particle vaccines.

Key words: Senecavirus A, intact particle, empty capsid, separation conditions, immunogenicity