Role of Specific Cell-Mediated Cytotoxicity in Protecting Fish from Viral Infections

Abstract

We report the in vivo role of specific cytotoxic cells in protecting fish from acute viral infections. Specifically, we found that (1) there is an inverse relationship between cytotoxic activities and viral load and (2) adoptive transfer of immune leukocytes prevented viral infection. Crucian carp hematopoietic necrosis virus (CHNV), which has a virulence to ginbuna crucian carp, was recently found and identified in Japan. Specific cell-mediated cytotoxicity of ginbuna leukocytes against CHNV-infected syngeneic cells was induced as a result of intraperitoneal inoculation with CHNV. This cytotoxicity was not induced against either virus-infected allogeneic cells or eel rhabidovirus- (EVA) infected syngeneic cells. In these respects, the cytotoxic activity was similar to that of mammalian cytotoxic T-lymphocyte (CTL) activity. Viral titers of tissues from infected fish were remarkably reduced 8 days after infections, when specific cytotoxic activity reached a peak. This result suggested that specific cytotoxic cells were responsible for the early control of CHNV replication. On the other hand, CHNV-specific antibody was greatly increased when the virus was eliminated by cytotoxic activities. The effectiveness of the virus-specific cytotoxicity was evaluated using adoptive cell transfer. Recipients that received leukocytes from immune syngeneic donors escaped CHNV infection. These findings suggest that virus-specific cytotoxic cells have a role in controlling viral infections in a fish.

Histologic, immunologic and endocrine biomarkers indicate contaminant effects in fishes of the Ashtabula River

“…This cell population is most known for activity against parasites and virally infected cells (Jaso-Freidmann et al 2000;Somamoto et al 2002). However, they are also tumoricidal in fish (Cuesta et al 2003).…”

Cell-mediated cytotoxicity in rainbow trout, Oncorhynchus mykiss, infected with viral haemorrhagic septicaemia virus

“…Allospecific cytotoxic cells were found in ginbunas, rainbow trout and channel catfish [4] and more strikingly, allogeneity between shark siblings appeared to be co-segregating with MHC class I alleles [26]. Further, specific CMC was shown against virus-infected autologous [12] and syngeneic [27] cells, but these studies lacked a concomitant characterization of the MHC class I sequences.…”

Characterization of Primary and Memory CD8 T-Cell Responses against Ranavirus (FV3) inXenopus laevis

“…However, not a lot is known about specific antiviral T-cell responses and their involvement in viral clearance and immunological memory in the lower vertebrates. For fish, T-cell receptors and MHC class I molecules have been characterized (19,23,32,34) and antiviral immune responses were shown to involve cytotoxicity mediated by peripheral blood lymphocytes of virusinfected cells (31,35). However, in the absence of MHCdefined strains, the evidence of the antigen specificity and MHC restriction of these lymphocytes is missing.…”