Innate immune response in common carp (Cyprinus carpio)

A comparative genomic approach was followed in this study to identify and characterize Toll like receptor from common carp fish. TLR7 gene was analyzed with respect to its structure and expression profile. Carp TLR7 cDNA is similar to that of the same family, Cyprinids. The conserved domains of TLR7 were identified in carp. Furthermore, the LRRs of known TLRs have a conserved region, was also found in carp species. The expression analysis of carp TLR7 in the healthy tissues was manifested in intestine, heart, head kidney, skin, muscles, liver, spleen, brain and gills. The TLR7 agonist (imiquimod) was used to recruit the pathway of TLR7 and leading to the production of type1 interferon and other cytokines (IL-1¿, TNF, IL-10, CXC chemokine, IL-12p35, IL-12p40, Mx protein, INF¿1, and INF¿2). In regard to different ligands of TLRs, we used LPS (TLR4 ligand), poly I:C (TLR3 ligand), and imiquimod (TLR7 ligand) to stimulate carp head kidney for different time range, 0, 1, 4, 8, 12, 24, and 48 hours and examined the cytokine genes level in respect to the dose used.