Cell-mediated cytotoxicity in rainbow trout, Oncorhynchus mykiss, infected with viral haemorrhagic septicaemia virus.
Mammalian cytotoxic T cells as part of the adaptive immune system recognize virus-infected target cells by binding of their T-cell receptors (TCR) to classical MHC class I molecules loaded with viral peptides. Our previous studies have shown that the allele of the single dominant polymorphic classical MHC class I locus Onmy-UBA is identical in the rainbow trout clone C25 and in the permanent rainbow trout cell line RTG-2. This enabled us to develop an assay to measure antiviral cytotoxicity in rainbow trout using a system of MHC class I-matched effector and target cells. Peripheral blood leucocytes (PBL) isolated from low dose viral haemorrhagic septicaemia virus (VHSV)-infected rainbow trout killed MHC class I-matched and later also xenogeneic MHC class I-mismatched VHSV-infected cells. When compared to PBL from uninfected control fish PBL from infected fish showed a higher transcriptional level of the CD8alpha gene which is a typical marker for mammalian cytotoxic T cells. Concurrently, the expression of the natural killer cell enhancement factor (NKEF)-like gene was enhanced as measured by real-time RT - PCR. Taken together, these results suggest that both innate and adaptive cell-mediated immune responses represented by NK and cytotoxic T cells, respectively, are triggered after VHSV infection. PBL that were able to kill VHSV-infected MHC class I-mismatched xenogeneic cells were generated later during infection than PBL capable of lysing VHSV-infected MHC class I-matched targets. This is contradictory to the generally accepted rule that innate immune mechanisms represent the first line of defence after viral infections.
Utke
Katrin
K
Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, D-17493 Greifswald-Insel Riems, Germany.
Bergmann
Sven
S
Lorenzen
Niels
N
Köllner
Bernd
B
Ototake
Mitsuru
M
Fischer
Uwe
U
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001798:Blood Proteins / Q000096:biosynthesis; D016827:CD8 Antigens / Q000096:biosynthesis; D002460:Cell Line; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D005393:Fish Diseases / Q000276:immunology* / Q000821:virology; D005805:Genes, MHC Class I / Q000276:immunology; D007962:Leukocytes / Q000166:cytology; D029141:Novirhabdovirus / Q000276:immunology*; D017686:Oncorhynchus mykiss / Q000276:immunology*; D018353:Rhabdoviridae Infections / Q000276:immunology / Q000662:veterinary*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D013997:Time Factors
D000914:Antibodies, Viral; D001798:Blood Proteins; D016827:CD8 Antigens