Banana lectin interactions with the immune system: Implications for future therapeutic applications

Abstract

Lectins are a highly diverse group of proteins whose biological functions have been associated with the carbohydrate binding activities. Banana lectin is a member of the jacalin-related family of lectins, and belongs to the glucose/mannose specific subgroup. However, it shows a unique specificity for internal α1,3 linkages as well as β1,3 linkages at the reducing termini in branched mannose oligosaccharides, which are components of the-core region of N-linked glycoproteins. As some other plant lectins, banana lectin is stable to the harsh conditions of the human gastrointestinal tract. As a small protein it seems to be able to pass the mucosal barrier and to reach the immune system inducing specific IgG4 antibodies. Banana lectin also displays T cell proliferation in CD3+, CD4+ and CD8+ populations of human PBMCs. It has been recently shown that in vitro stimulation of Balb/c and C57 BL/6 splenocytes by the recombinantly produced banana lectin resulted in the proliferation of T cells and an increased secretion of interferon-gamma. Due to its notable immunomodulatory potential, it has been proposed for the treatment of some Th2-related disorders. This work will discuss banana lectin interactions with the immune system and consider implications for future therapeutic applications.