Takami Ikuo, Kwon Se Ryun, Nishizawa Toyohiko, Yoshimizu Mamoru
Nagasaki Prefectural Institute of Fisheries, Taira, Nagasaki 851-2213, Japan.
Dis Aquat Organ. 2010 Mar 9;89(2):109-15. doi: 10.3354/dao02185.
In immunization of fish with polyinosinic-polycytidylic acid (poly[I:C], a synthetic double-stranded RNA, injection of Poly(I:C) followed by challenge with a live virus induces a transient, non-specific antiviral state by interferon activity. When exposed to a virus while in this antiviral state, the fish acquire a specific and protective immunity against the corresponding viral disease and survive. In the present study, the effiacy of Poly(I:C) immunization was investigated in japanese flounder Paralichthys olivaceus using viral hemorrhagic septicemia virus (VHSV) as a model; the minimum dose of Poly(I:C) required for inducing protection and the duration of the antiviral state were determined, and a potentially curative effect of Poly(I:C) administration was assessed. The antiviral state was induced by administration of Poly(I:C) doses ranging from 12.5 to 200 microg fish(-1). Minimum dose to induce the antiviral state (relative percentage survival, RPS: 90%) was 12.5 microg fish(-1). No curative effect of Poly(I:C) was observed in fish pre-infected with VHSV. Fish injected with 200 microg Poly(I:C) fish(-1) were highly protected (RPS: 100%) from an artificial challenge with VHSV, and specific antibodies against VHSV were detected. The corresponding high level of antiviral state against VHSV was attained 1 d post Poly(I:C) injection, lasted for 6 d and susequently decreased. Moreover, the surviving fish were highly protected from re-challenge with VHSV (RPS: 100%). Thus, it was considered that an immunity against viral hemorrhagic septicemia was induced in the Japanese flounder by injecting live VHSV following Poly(I:C) administration.
用聚肌苷酸-聚胞苷酸（poly[I:C]，一种合成双链RNA）对鱼类进行免疫时，注射poly[I:C]后再用活病毒攻击，可通过干扰素活性诱导短暂的非特异性抗病毒状态。处于这种抗病毒状态时，鱼类接触病毒后可获得针对相应病毒性疾病的特异性保护性免疫并存活。在本研究中，以病毒性出血性败血症病毒（VHSV）为模型，研究了poly[I:C]免疫对日本牙鲆（Paralichthys olivaceus）的效果；确定了诱导保护所需的poly[I:C]最小剂量以及抗病毒状态的持续时间，并评估了poly[I:C]给药的潜在治疗效果。通过给予12.5至200微克/鱼（-1）剂量的poly[I:C]诱导抗病毒状态。诱导抗病毒状态的最小剂量（相对存活率，RPS：90%）为12.5微克/鱼（-1）。在预先感染VHSV的鱼中未观察到poly[I:C]的治疗效果。注射200微克/鱼（-1）poly[I:C]的鱼对VHSV人工攻击具有高度保护作用（RPS：100%），并检测到针对VHSV的特异性抗体。注射poly[I:C]后1天达到针对VHSV的相应高水平抗病毒状态，持续6天，随后下降。此外，存活的鱼对VHSV再次攻击具有高度保护作用（RPS：100%）。因此，认为通过在给予poly[I:C]后注射活VHSV，可在日本牙鲆中诱导针对病毒性出血性败血症的免疫。
