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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #244440
Title: T-cell receptor accessory and co-receptor molecules in channel catfish

Author
item Quiniou, Sylvie
item SAHOO, M - University Of Mississippi Medical Center
item BENGTEN, E - University Of Mississippi Medical Center
item WILSON, M - University Of Mississippi Medical Center

Submitted to: Society of Developmental Comparative Immunology
Publication Type: Abstract Only
Publication Acceptance Date: 5/28/2009
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: T cell receptor (TCR) associated invariant chains CD3gamma/delta,epsilon, and zeta as well as TCR co-receptors CD8alpha and CD8beta were isolated from the channel catfish, Ictalurus punctatus, at both the gene and cDNA levels. All of catfish CD3 sequences encode for proteins that resemble their respective teleost and mammalian counterparts. CD3 gamma/delta and CD3epsilon each contain a single immune-receptor tyrosine-based activation motif (ITAM) in their cytoplasmic tails (CYT), while the CYT of CD3zeta has three ITAMs. As expected, sequence and phylogenetic analyses show that catfish CD3gamma/delta, CD3epsilon, and CD3zeta cluster at high bootstrap values with their respective teleost counterparts and message for all three of the CD3 chains are expressed in catfish clonal T cell lines, but not in catfish clonal B cells or macrophages. Furthermore, as a complement to this T cell marker study, the genes encoding catfish CD8alpha and CD8beta were also identified using degenerate PCR protocols and “Positional degenerate sequencing” on Bacterial Artificial Chromosome (BAC). As above, both encode for proteins that resemble other teleost and mammalian CD8alpha and CD8beta proteins, respectively. The catfish CD8 molecules each contain a typical leader peptide, an extracellular immunoglobulin domain and hinge, followed by a transmembrane region and CYT. As noted previously for teleost CD8 molecules, the catfish CD8alpha and CD8beta hinge regions are predicted to be O-glycosylated and their CYTs each contain a C-X-H amino acid motif, instead of the typical tyrosine kinase p56lck interacting C-X-C motif found in mammals. Preliminary studies using RT-PCR analyses demonstrate that catfish CD8alpha and CD8beta message is highly expressed in thymus, spleen, pronephros, gills. Together the identification of these important T cell molecules will allow for the development of needed pan and subtype specific anti-catfish T cell monoclonal antibodies.