Carp interleukin-1β in the role of an immuno-adjuvant

The transforming growth factor (TGFβ) family of proteins are a set of pleiotropic secreted signalling molecules with unique and potent immunoregulatory properties. In this study the molecular cloning of carp TGFβ1is reported. A partial cDNA of the TGFβ protein was initially identified from a cDNA pool, obtained by subtracting the cDNAs from Con A-induced carp head kidney leucocytes from uninduced carp head kidney leucocyte cDNA. The entire coding sequence was assembled by sequencing both ends of the cDNA clone by using an anchored PCR reaction. Sequence analysis revealed an ORF encoding a protein of 376 amino acids, containing the similar unique pattern of conserved cysteines (seven out of nine) in the cysteine knot structure which exists in all known TGFβ proteins. Compared with other animal TGFβs, the cDNA clone shows approximately 59–42, 40–38 and 37–36% amino acid identity with TGFβ1, TGFβ3and TGFβ2respectively. Carp TGFβ1is expressed at low levels in carp head kidney, spleen, egg and liver, whereas its messenger RNA level is increased after activation of the head kidney leucocytes with Con A. Sequence analysis and pattern of expression suggests that this is the carp TGFβ1.