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In this paper, we firstly reported a C-type lectin cDNA clone of1029 bps from the larvae of A. Pernyi (Ap-CTL) using PCR andRACE techniques. The full-length cDNA contains an openreading frame encoding 308 amino acid residues which hastwo different carbohydrate-recognition domains (CRDs) arrangedin tandem. To investigate the biological activities in theinnate immunity, recombinant Ap-CTL was expressed in E. coliwith a 6-histidine at the amino-terminus (Ap-rCTL). Besidesacted as a broad-spectrum recognition protein binding to awide range of PAMPs and microorganisms, Ap-rCTL also hadthe ability to recognize and trigger the agglutination of bacteriaand fungi. In the proPO activation assay, Ap-rCTL specificallyrestored the PO activity of hemolymph blocked by anti-Ap-rCTL antibody in the presence of different PAMPs ormicroorganisms. In summary, Ap-rCTL plays an important rolein insect innate immunity as an pattern recognition protein.[BMB Reports 2013; 46(7): 358-363]

Pattern recognition receptors are known to participate in theactivation of Prophenoloxidase system. In this study, a1,3-β-D-glucan recognition protein was detected for the firsttime in Antheraea pernyi larvae (Ap-βGRP). Ap-βGRP waspurified to 99.9% homogeneity from the hemolymph usingtraditional chromatographic methods. Ap-βGRP specificallybind 1,3-β-D-glucan and yeast, but not E. coli or M. luteus.The 1,3-β-D-glucan dependent phenoloxidase (PO) activity ofthe hemolymph inhibited by anti-Ap-βGRP antibody could berecovered by addition of purified Ap-βGRP. These resultsdemonstrate that Ap-βGRP acts as a biosensor of 1,3-β-Dglucanto trigger the Prophenoloxidase system. A trace mountof 1,3-β-D-glucan or Ap-βGRP alone was unable to trigger theproPO system, but they both did. Ap-βGRP was specificallydegraded following the activation of proPO with 1,3-β-Dglucan.These results indicate the variation in the amount ofAp-βGRP after specific immune challenge in A. pernyihemolymph is an important regulation mechanism to immuneresponse. [BMB Reports 2013; 46(5): 264-269]