A single-CRD C-type lectin is important for bacterial clearance in the silkworm

作者：Zhan, Ming-Yue; Shahzad, Toufeeq; Yang, Pei-Jin; Liu, Su; Yu, Xiao-Qiang; Rao, Xiang-Jun^*

来源：Developmental and Comparative Immunology, 2016, 65: 330-339.

DOI：10.1016/j.dci.2016.08.004

• Insect immunity
• Silkworm
• C-type lectin

C-type lectins (CTLs) depend on the carbohydrate-recognition domain (CRD) to recognize carbohydrates by a Cat-dependent mechanism. In animals, CTLs play critical roles in pathogen recognition, activation of the complement system and signaling pathways. Immulectins (Dual-CRD CTLs) in lepidopteran are involved in recognizing pathogens. However, little is known about the immune-related functions of insect single-CRD CTLs. Here, we reported the characterization of C-type lectin-S3 (CTL-S3), a single-CRD CTL from the domesticated silkmoth Bombyx mori (Lepidoptera: Bombycidae). The ORF of CTL-S3 gene is 672 bp, which encodes a putative protein of 223 amino acids. CTL-S3 gene was expressed in a variety of tissues. Levels of CTL-S3 mRNA in fertilized eggs and whole larvae were elevated upon bacterial challenges. CTL-S3 was secreted to larval hemolymph. The recombinant protein (rCTL-S3) binds to bacterial cell wall components and bacteria. CTL-S3 inhibited the growth of Bacillus subtilis and caused agglutination of Staphylococcus aureus. More importantly, CTL-S3 facilitated the rapid clearance of Escherichia coli and Staphylococcus aureus from the body cavity of larvae. Taken together, our results suggested that CTL-S3 may function as an opsonin in larval hemolymph to enhance the clearance of pathogens.

• 出版日期2016-12
• 单位安徽农业大学