JACALIN - AN IGA-BINDING LECTIN

  • 1 January 1985
    • journal article
    • research article
    • Vol. 134  (3) , 1740-1743
Abstract
Seeds of Artocarpus integrifolia (jackfruit) contain a lectin, called jacalin, that is both a potent T cell mitogen and an apparently T cell-independent activator of human B cells for the secretion of Ig. During the above experiments a massive precipitation in cell cultures stimulated with .gtoreq. 100 .mu.g of lectin was noted. The precipitate is formed after the interaction of jacalin and the serum protein added to the culture medium. More importantly, it was demonstrated that IgA is probably the major serum constituent precipitated by the lectin and that no IgG or IgM can be detected in the precipitates. In secretions such as colostrum, IgA is the only protein precipitated by jacalin. On the basis of this specificity a simple and reliable affinity chromatography procedure is described for the purification of both human serum and colostrum IgA. Jacalin is a D-Gal binding lectin and should be a useful tool for studying of serum and secretory IgA.