Molecular cloning of the β subunit of complement component eight of rainbow trout

Abstract

Complement-mediated killing of pathogens through the lytic pathway is an important effector mechanism of the innate immune response. C8 is one of the components of the lytic pathway and is composed of an α, β, and γ subunit. In the present study we report the cloning and characterization of the primary structure of the C8β subunit in the rainbow trout ( Oncorhynchus mykiss). The deduced amino acid sequence of trout C8β shows 72 and 47% identity with that of Japanese flounder and human, respectively. It also contains many of the same structural motifs as those found in mammalian lytic components. The C8β gene appears to exists as a single copy in the trout genome and is expressed primarily in the liver. The protein encoded by the gene was identified by Western blotting using an anti-peptide antibody and was approximately 65 kDa.