Modulation of functional properties of galectin-3 by monoclonal antibodies binding to the non-lectin domains

Biochemistry. 1996 May 14;35(19):6073-9. doi: 10.1021/bi952716q.


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 amino-terminal 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 125I-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 galectin-3, and the inhibitory activity of MAb B2C10 is probably the result of its disruption of the self-association process.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / metabolism*
  • Antigens, Differentiation / immunology
  • Antigens, Differentiation / metabolism*
  • Base Sequence
  • Binding Sites, Antibody*
  • Cell Membrane / metabolism
  • DNA Primers
  • Epitopes / metabolism
  • Galectin 3
  • Hemagglutination Tests
  • Humans
  • Immunoglobulin E / metabolism
  • Lectins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Neutrophils / immunology


  • Antibodies, Monoclonal
  • Antigens, Differentiation
  • DNA Primers
  • Epitopes
  • Galectin 3
  • Lectins
  • Immunoglobulin E