Hirame rhabdovirus (HIRRV) is one of the four recognized species within the Novirhabdovirus genus, represented by the type species Infectious Haematopoietic Necrosis (IHNV). HIRRV was first isolated during an outbreak on cultured flounder (Paralichthys olivaceus) and ayu (Plecoglossus altivelis) in Japan. It was also found on other marine fish in Asia, such as stone flounder (Kareius bicoloratus) in China. Furthermore, it was shown to be pathogenic for a range of salmonids species, including rainbow trout, experimentally challenged in freshwater. The major clinical signs of HIRRV infection were congestion of the gonads, focal hemorrhages of the skeletal muscle and fins and ascitic fluid collection (Borzym et al., 2012).
Vaccination Protocol:
Five groups of forty flounder fry with a mean weight of 3 g were prepared for injection with pcDNA-G, pcDNA-N, a pcDNA-G and pcDNA-N mixture, pcDNA3.1(+) vector, or PBS (Seo et al., 2006).
Vaccine Immune Response Type:
VO_0003057
Immune Response:
Both cellular and humoral immune responses are involved in the protection of fish immunized with DNA vaccine. Induction of specific antibody response has been observed from rainbow trout immunized with rhabdovirus G protein constructs. However, despite high levels of protection, neutralizing antibodies could not be detected in all vaccinated fish at the time of challenge, or survivors of the challenge (Seo et al., 2006).
Challenge Protocol:
At 21 days post vaccination, flounder fry injected with different DNA vaccines were challenged by immersion in water containing 1.2 × 104 TCID ml−1 HIRRV (Seo et al., 2006).
Efficacy:
Groups injected with the pcDNA-G showed only 5% cumulative mortality. Control groups injected with plasmid only or PBS only showed at least 95% mortality. These results demonstrated the protective effect of this DNA vaccine against HIRRV infection (Seo et al., 2006).
Vaccination Protocol:
Five groups of forty flounder fry with a mean weight of 3 g were prepared for injection with pcDNA-G, pcDNA-N, a pcDNA-G and pcDNA-N mixture, pcDNA3.1(+) vector, or PBS (Seo et al., 2006).
Vaccine Immune Response Type:
VO_0003057
Immune Response:
Both cellular and humoral immune responses are involved in the protection of fish immunized with DNA vaccine. Induction of specific antibody response has been observed from rainbow trout immunized with rhabdovirus G protein constructs. However, despite high levels of protection, neutralizing antibodies could not be detected in all vaccinated fish at the time of challenge, or survivors of the challenge (Seo et al., 2006).
Challenge Protocol:
At 21 days post vaccination, flounder fry injected with different DNA vaccines were challenged by immersion in water containing 1.2 × 10^4 TCID ml−1 HIRRV (Seo et al., 2006).
Efficacy:
Groups injected with the mixed pcDNA-N+pcDNA-G vaccine showed only 2.5% cumulative mortality. Control groups injected with plasmid only or PBS only showed at least 95% mortality. These results demonstrated the protective effect of this DNA vaccine against HIRRV infection (Seo et al., 2006).
3. H. rhabdovirus DNA vaccine pHRV-G encoding HIRRV and VHSV G proteins
Immune Response:
A type I IFN system was stimulated by vaccination with pHRV-G in the Japanese flounder, which contributes not only to innate immunity but also to acquired immunity. In addition, type I IFN plays a role in Th1 polarization of the immune response induced by DNA vaccination (Yasuike et al., 2007).
Efficacy:
Fourteen days after the HIRRV challenge, cumulative mortalities of the fish injected with pHRV-G was 13%, as compared to the cumulative mortalities of the control group which was at 98%. This confirmed previous protection studies which demonstrated the efficacy of this vaccine (Yasuike et al., 2007).
2. Seo et al., 2006: Seo JY, Kim KH, Kim SG, Oh MJ, Nam SW, Kim YT, Choi TJ. Protection of flounder against hirame rhabdovirus (HIRRV) with a DNA vaccine containing the glycoprotein gene. Vaccine. 2006; 24(7); 1009-1015. [PubMed: 16176849].
3. Yasuike et al., 2007: Yasuike M, Kondo H, Hirono I, Aoki T. Difference in Japanese flounder, Paralichthys olivaceus gene expression profile following hirame rhabdovirus (HIRRV) G and N protein DNA vaccination. Fish & shellfish immunology. 2007; 23(3); 531-541. [PubMed: 17449275].
