Modulation of functional properties of galectin-3 by monoclonal antibodies binding to the non-lectin domains
Modulation of functional properties of galectin-3 by monoclonal antibodies binding to the non-lectin domains
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DOI：
10.1021/bi952716q
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发表时间：
1996-05-14
期刊：
影响因子：
2.9
通讯作者：
Chen, SS
中科院分区：
文献类型：
--
作者：
Liu, FT;Hsu, DK;Chen, SS
Galectin-3是一个新定义的动物凝集素家族的成员，它由三个结构域组成：一个小的氨基末端结构域，一个包含重复元件的结构域，以及一个包含碳水化合物识别位点的羧基末端结构域。关于这种凝集素的各种功能已经被描述或提出，并且Galectin-3似乎具有不同的作用。用重组人Galectin-3或Galectin-3C(羧基末端结构域)超免疫小鼠，制备了小鼠单抗，并对7株单抗进行了详细鉴定。根据完整的Galectin-3产生的所有单抗都识别该分子的氨基末端区域，如用重组Galectin-3C和Galectin-3NR进行的ELISA和免疫印迹所证明的那样，它包含氨基端结构域和所有的重复元件。它们的表位都在Galectin-3的前45个氨基酸范围内，通过使用氨基端截短的Galectin-3突变体确定。然而，这些单抗被发现深刻地调节Galectin-3的凝集素活性。单抗B2C10可抑制(I)标记Galectin-3与包被在微滴板上的Ig E的结合；(Ii)Galectin-3‘S血凝活性；(Iii)Galectin-3诱导人中性粒细胞产生超氧阴离子自由基。其他单抗，特别是A3A12，可显著增强这些活性。结果支持我们的模型，即Galectin-3的凝集素功能受到分子氨基末端区域自结合导致的蛋白质同源二聚的影响。某些单抗的增强活性可能是由于促进了Galectin-3的二聚化，而单抗B2C10的抑制活性可能是由于其破坏了自结合过程。
Galectin-3 is a member of a newly defined family of animal lectins, which is composed of three domains: a small amino-terminal domain, a domain containing repeating elements, and a carboxyl-terminal domain containing the carbohydrate-recognition site. Various functions have been described or proposed for this lectin, and it appears that galectin-3 has diverse roles. Murine monoclonal antibodies (MAbs) have been generated from mice hyperimmunized with recombinant human galectin-3 or galectin-3C (the carboxyl-terminal domain), and seven MAbs have been characterized in detail. All MAbs generated against the intact galectin-3 recognize the amino-terminal region of the molecule, as demonstrated by ELISA and immunoblotting using recombinant galectin-3C and galectin-3NR, which contains the aminoterminal domain and all the repeating elements. Their epitopes were all found to be within the first 45 amino acids of galectin-3, as determined by using galectin-3 mutants with a truncated amino-terminal region. However, these MAbs were found to profoundly modulate the lectin activities of galectin-3. The MAb B2C10 inhibited (i) the binding of I-125-labeled galectin-3 to IgE coated on microtiter plates; (ii) the galectin-3's hemagglutination activity; and (iii) galectin-3-induced superoxide production by human neutrophils. Other MAbs, especially A3A12, caused marked potentiation of these activities. The results support our model that the lectin function of galectin-3 is influenced by protein homodimerization resulting from self-association of the amino-terminal region of the molecule. The potentiating activities of some MAbs are probably due to facilitation of dimerization of galectin-3, and the inhibitory activity of MAb B2C10 is probably the result of its disruption of the self-association process.