Rhabdovirus Infection Induces Public and Private T Cell Responses in Teleost Fish

Abstract

Many viruses induce a strong T cell response that contributes to the elimination of infected cells presenting viral peptides by MHC molecules. The structure and expression of genes encoding molecules homologous to mammalian αβ TCRs have been recently characterized in rainbow trout and in several teleost species, but the αβ T cell response against pathogens has not been directly demonstrated. To study the modifications of the T cell repertoire during an acute viral infection in rainbow trout, we adapted the immunoscope methodology, which consists of spectratyping the complementarity-determining region 3 length of the TCRβ chain. We showed that the naive T cell repertoire is polyclonal and highly diverse in the naive rainbow trout. Using viral hemorrhagic septicemia virus (VHSV), which provokes an acute infection in rainbow trout, we identified skewed complementarity-determining region 3 size profiles for several VβJβ combinations, corresponding to T cell clonal expansions during primary and secondary response to VHSV. Both public and private T cell expansions were shown by immunoscope analysis of spleen cells from several infected individuals of a rainbow trout clone sharing the same genetic background. The public response to VHSV consisted of expansion of Vβ4Jβ1 T cell, which appeared early during the primary response and was strongly boosted during the secondary response.

A Review of Immune System Components, Cytokines, and Immunostimulants in Cultured Finfish Species

“…Consequently, the TCRβ re-gion has been found to undergo recombination and is immensely involved with viral recognition [43]. It was found that large populations of T cells inhabit the thymus, while they are also present in kidney and splenic regions following development [38].…”

Costimulatory Receptors in a Teleost Fish: Typical CD28, Elusive CTLA4

“…We have previously shown that VHSV, a fish rhabdovirus, induced a strong T cell response in rainbow trout (38). To determine whether the expression of rbtCD28 and rbtCTLA4 are modified in vivo, we experimentally infected rainbow trout with an attenuated strain FIGURE 3.…”

“…Autologous cell-mediated specific lysis of virus-infected syngenic target cells has also been reported in cloned goldfish (36,37). Finally, both public and private T cellspecific expansions have been observed in rainbow trout during secondary immune responses to viral hemorrhagic septicemia virus (VHSV), 3 a fish rhabdovirus, using TCR-␤ CDR3-length spectratyping (38). TCR-MHC-peptide interactions induce signaling events through CD3 in mammals and most likely in lower vertebrates because a complete set of CD3 genes, including TCR, CD3⑀, and CD3␥␦, has been found in Pufferfish and Xenopus (39,40).…”

Primary Structure and Complementarity-Determining Region (CDR) 3 Spectratyping of Rainbow Trout TCRβ Transcripts Identify Ten Vβ Families with Vβ6 Displaying Unusual CDR2 and Differently Spliced Forms

“…It results from successive introductions between 1976 and 1983 of several domestic populations from the United States and France, which were pooled and then maintained as a single population by random mating during four to five generations. For the study of the V␤6 response to the VHSV, rainbow trout heterozygous clones (22) were used. Trout were sacrificed by overexposure to 2-phenoxyethanol diluted 1/1000.…”

“…Spectratyping of CDR3 revealed that the rainbow trout naive T cell repertoire is polyclonal and highly diverse. Primary and secondary infection with viral hemorrhagic septicemia virus (VHSV) dramatically skewed the repertoire, and the profiles were reminiscent of the public and private virus-specific T cell responses observed in mammals (22).…”