IDENTIFICATION OF TOLL-LIKE RECEPTOR LIGANDS IN CHANNEL CATFISH

The major goal of this study is to identify channel catfish TLR MAMPs. For this project we have taken advantage of a mammalian cell reporter system. We have successfully expressed catfish TLR7 in mammalian cells and shown that NF-kB activation occurs after stimulation with imiquimod, a known mammalian TLR7 agonist. My goal is to continue to transfect other catfish TLRs into this reporter cell line and determine their ligands. In addition, it is known in mammals that TLR2 and TLR6 have the ability to heterodimerize. This allows for recognition of different MAMPs than those recognized by either TLR2 or TLR6 when they homodimerize. It is also hypothesized that the TLR1 family, which is expanded in catfish, has a similar ability to heterodimerize. Catfish TLRs 1, 18, and 25 are all thought to have the potential to heterodimerize with TLR2 in catfish, which would allow the recognition of alternative ligands. This leads to our other goal, which is to expand the knowledge of catfish TLRs heterodimerization patterns and identify additional MAMPs that can be recognized through these combinations.