John D. Hansen

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During the analysis of Ig superfamily members within the available rainbow trout (Oncorhynchus mykiss) EST gene index, we identified a unique Ig heavy-chain (IgH) isotype. cDNAs encoding this isotype are composed of a typical IgH leader sequence and a VDJ rearranged segment followed by four Ig superfamily C-1 domains represented as either membrane-bound or(More)
The DNA vaccine based on the glycoprotein gene of Infectious hematopoietic necrosis virus induces a non-specific anti-viral immune response and long-term specific immunity against IHNV. This study characterized gene expression responses associated with the early anti-viral response. Homozygous rainbow trout were injected intra-muscularly (I.M.) with vector(More)
One of the most unexpected discoveries in MHC genetics came from studies dealing with the teleost MHC. Initially discovered in zebrafish, the MHC class I and II regions of all bony fish are not linked. Previous segregation analysis in trout suggested that the class I and II regions reside on completely different chromosomes. To learn more about MHC genomics(More)
A large multigene family of NOD-like receptor (NLR) molecules have been described in mammals and implicated in immunity and apoptosis. Little information, however, exists concerning this gene family in non-mammalian taxa. This current study, therefore, provides an in-depth investigation of this gene family in lower vertebrates including extensive(More)
The gene encoding IgH δ has been found in all species of teleosts studied to date. However, catfish (Ictalurus punctatus) is the only species of fish in which a secretory form of IgD has been characterized, and it occurs through the use of a dedicated δ-secretory exon, which is absent from all other species examined. Our studies have revealed that rainbow(More)
Members of the bacterial genus Francisella are highly virulent and infectious pathogens. New models to study Francisella pathogenesis in evolutionarily distinct species are needed to provide comparative insight, as the mechanisms of host resistance and pathogen virulence are not well understood. We took advantage of the recent discovery of a novel species(More)
The rainbow trout (Oncorhynchus mykiss) is one of the most widely studied of model fish species. Extensive basic biological information has been collected for this species, which because of their large size relative to other model fish species are particularly suitable for studies requiring ample quantities of specific cells and tissue types. Rainbow trout(More)
This brief review is intended to provide a concise overview of the current literature concerning T cells, advances in identifying distinct T cell functional subsets, and in distinguishing effector cells from memory cells. We compare and contrast a wealth of recent progress made in T cell immunology of teleost, elasmobranch, and agnathan fish, to knowledge(More)
 One component of antigen receptor diversity shared by all gnathostomes characterized to date is mediated by a unique DNA polymerase, terminal deoxynucleotidyl transferase (TdT), which generates significant functional diversity during immunoglobulin and T-cell receptor rearrangement. To gain further insight into the evolutionary origin(s) of this unique(More)
CD28 family of costimulatory receptors is comprised of molecules with a single V-type extracellular Ig domain, a transmembrane and an intracytoplasmic region with signaling motifs. CD28 and cytotoxic T lymphocyte antigen-4 (CTLA4) homologs have been recently identified in rainbow trout. Other sequences similar to mammalian CD28 family members have now been(More)