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The lectin jacalin triggers CD4‐mediated lymphocyte signaling by binding CD4 through a protein‐protein interaction
Author(s) -
Lafont Virginie,
Domand Jacques,
Covassin Laurence,
Liautard Jean Pierre,
Favero Jean
Publication year - 1996
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.59.5.691
Subject(s) - jacalin , lectin , biology , oligosaccharide , c type lectin , microbiology and biotechnology , t cell , hapten , concanavalin a , signal transduction , cell , biochemistry , immunology , in vitro , antigen , immune system
The lectin jacalin specifically stimulates lymphocytes expressing the CD4 antigen. Recent studies have also demonstrated that this lectin interacts with CD4, inhibits in vitro HIV infection, and triggers cell signaling directly via CD4. Jacalin as a lectin was suggested to trigger CD4‐mediated cell signaling by interacting with the oligosaccharide side chains of CD4 located on Asn 271 and Asn 300 . Such a hypothesis was of importance because it implied that the glycosylated chains could represent a functional domain directly involved in CD4‐related cell activation. We analyzed this possibility by studying the effect of hapten sugars on jacalin‐induced CD4 cell signaling and jacalin/CD4 interaction, and by studying the binding capacities of the lectin toward glycosylated, deglycosylated, and unglycosylated CD4. The results presented in this study provide evidence that jacalin does not recognize the CD4 oligosaccharide chains and actually binds CD4 through a specific protein‐protein interaction; as a consequence these results rule out the involvement of the CD4 saccharide moieties in CD4‐mediated cell signaling triggered by the lectin.