The potent IgG4-inducing antigen in banana is a mannose-binding lectin, BanLec-I

Int Arch Allergy Immunol. 1992;97(1):17-24. doi: 10.1159/000236090.


IgG4 antibodies to banana were found to occur far more frequently than expected. The most important antigen involved proved to be a lectin, BanLec-I. Because of the lectin nature of the antigen, it was important to establish the antibody nature of the lectin-IgG4 interaction and to exclude an interaction between the sugar-binding site of the lectin and glycosidic chains on IgG4. Three arguments in support of immune binding are: (1) the binding of BanLec-I to IgG4 is mannoside resistant, whereas the binding to all other glycoproteins tested is mannoside inhibitable; (2) only a minor fraction of the IgG4 in serum and none of five IgG4 myelomas tested was bound, and (3) the lectin binds to the Fab fragment of the IgG4 molecule. A curious finding was that in the presence of high-molecular-weight glycoproteins the interaction between IgG4 and BanLec-I was enhanced by alpha-methyl mannoside. The probable explanation of this phenomenon is that complexes of the lectin with high-molecular-weight glycoproteins by sterical interference inhibit the interaction with human IgG4 antibodies (or with rabbit antibodies to the lectin). This inhibition is prevented in the presence of alpha-methyl mannoside. These results support the earlier suggestion that some lectins are particularly prone to induce an immune response upon oral feeding. This banana lectin might be a potentially useful carrier protein for oral antihapten immunization in humans.

MeSH terms

  • Antigens / immunology*
  • Complement C3 / physiology
  • Fruit / immunology*
  • Humans
  • Immunoglobulin G / biosynthesis*
  • Immunoglobulin G / immunology
  • Lectins / immunology*
  • Mannose / metabolism*
  • Molecular Weight
  • Plant Lectins


  • Antigens
  • BanLec-I
  • Complement C3
  • Immunoglobulin G
  • Lectins
  • Plant Lectins
  • Mannose