A novel pattern recognition protein of the Chinese oak silkmoth， Antheraea pernyi， is involved in the pro-PO activating system.

In this paper， we firstly reported a C-type lectin cDNA clone of 1029 bps from the larvae of A. Pernyi (Ap-CTL) using PCR and RACE techniques. The full-length cDNA contains an open reading frame encoding 308 amino acid residues which has two different carbohydrate-recognition domains (CRDs) arranged in tandem. To investigate the biological activities in the innate immunity， recombinant Ap-CTL was expressed in E. coli with a 6-histidine at the amino-terminus (Ap-rCTL). Besides acted as a broad-spectrum recognition protein binding to a wide range of PAMPs and microorganisms， Ap-rCTL also had the ability to recognize and trigger the agglutination of bacteria and fungi. In the proPO activation assay， Ap-rCTL specifically restored the PO activity of hemolymph blocked by anti- Ap-rCTL antibody in the presence of different PAMPs or microorganisms. In summary， Ap-rCTL plays an important role in insect innate immunity as an pattern recognition protein.