Zhu Yong, Ng Patricia M L, Wang Lihui, Ho Bow, Ding Jeak Ling
Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.
Int Immunol. 2006 Dec;18(12):1671-80. doi: 10.1093/intimm/dxl101. Epub 2006 Oct 11.
Carbohydrate-binding lectins play essential roles as pattern recognition receptors in innate immunity in both vertebrates and invertebrates. The carcinolectins 5 (CL5a and CL5b, the CL5 isoforms of horseshoe crab, Carcinoscorpius rotundicauda, with apparent sizes of 36 and 40 kDa, respectively) are prominent plasma lectins that bind all representative microbes and pathogen-associated molecular pattern molecules. Different cDNA isoforms of both CL5a and CL5b were isolated, leading to our speculation on their functional divergence. Characterization of CL5 isoforms bound to microbial cell surfaces demonstrates the diversity of these lectins. The resolution patterns of the isoforms that associate with fungus differ from those that associate with bacteria, suggesting the unique roles these lectins play in the recognition and differentiation of microbes. We postulate that different populations of plasma lectins act in collaboration in frontline innate immune defense against disparate pathogens. The functional diversity of lectins in invertebrates appears to evolutionarily compensate for the lack of acquired immunity.
碳水化合物结合凝集素作为模式识别受体在脊椎动物和无脊椎动物的先天免疫中发挥着重要作用。癌凝集素5（CL5a和CL5b，圆尾鲎（Carcinoscorpius rotundicauda）的CL5亚型，表观大小分别为36 kDa和40 kDa）是突出的血浆凝集素，可结合所有代表性微生物和病原体相关分子模式分子。CL5a和CL5b的不同cDNA亚型被分离出来，这引发了我们对它们功能差异的推测。与微生物细胞表面结合的CL5亚型的特性表明了这些凝集素的多样性。与真菌结合的亚型的分辨模式与与细菌结合的亚型不同，这表明这些凝集素在微生物识别和区分中发挥着独特作用。我们推测，不同群体的血浆凝集素在针对不同病原体的一线先天免疫防御中协同作用。无脊椎动物中凝集素的功能多样性似乎在进化上弥补了获得性免疫的不足。
