Inactivated infectious haematopoietic necrosis virus (IHNV) vaccines

Abstract

The inactivation dynamics of infectious haematopoietic necrosis virus (IHNV) by b-propiolactone (BPL), binary ethylenimine (BEI), formaldehyde or heat and the antigenic and immunogenic properties of the inactivated vaccines were evaluated. Chemical treatment of IHNV with 2.7 mm BPL, 1.5 mm BEI or 50 mm formaldehyde abolished virus infectivity within 48 h whereas heat treatment at 50 or 100 degrees C rendered the virus innocuous within 30 min. The inactivated IHNV vaccines were recognized by rainbow trout, Oncorhynchus mykiss, IHNV-specific antibodies and were differentially recognized by antigenic site I or antigenic site II IHNV glycoprotein-specific neutralizing monoclonal antibodies. The BPL inactivated whole virus vaccine was highly efficacious in vaccinated rainbow trout challenged by waterborne exposure to IHNV 7, 28, 42 or 56 days (15 degrees C) after immunization. The formaldehyde inactivated whole virus vaccine was efficacious 7 or 11 days after vaccination of rainbow trout but performed inconsistently when tested at later time points. The other vaccines tested were not efficacious.

Inactivated virus vaccines from chemistry to prophylaxis: merits, risks and challenges

“…In another study, HNV inactivated at 50°C did not protect fish against challenge. The percentage mortality of fish in the vaccinated groups was not statistically different compared with the mortality of fish in either the mock-vaccinated or unhandled control groups [67].…”

“…After vaccination of pigs with BEI-inactivated PRRSV, they induced a virus-specific and virus-neutralize antibody response, which was able to reduce viremia after challenge [79]. However, rainbow trout vaccinated with BEI-inactivated HNV and challenged with live HNV showed no statistically significant differences between the cumulative percentage mortality in the group of fish immunized with the BEI vaccines and the mortality of fish in the mock-vaccinated control groups when tested 28 or 56 days after vaccination [67].…”

“…However, BPL-inactivated influenza showed reduced hemagglutinin and neuraminidase activity [62]. Vaccines based on BPL-inactivated virus against SARS-CoV [64], hematopoietic necrosis virus (HNV) [67] and influenza [65], were able to protect on challenge.…”

“…Heat inactivation has been studied as a method to develop a KV vaccine for SARS-CoV [30], HIV [87] and HNV (Table 7) [67]. To test the ability of heat to inactivate the SARS-CoV, Darnell et al incubated the virus at three temperatures (56, 65 and 75°C) for increasing periods of time [30].…”

“…BEI is used for the inactivation of many viruses, such as FMDV [70], RRV [75], sheep pox [76], HIV [77], Nipah virus [78], HNV [67] and PRRSV (Table 6) [79].…”