Escherichia coli heat-labile enterotoxin B subunit is a more potent mucosal adjuvant than its vlosely related homologue, the B subunit of cholera toxin.
Although cholera toxin (Ctx) and Escherichia coli heat-labile enterotoxin (Etx) are known to be potent mucosal adjuvants, it remains controversial whether the adjuvanticity of the holotoxins extends to their nontoxic, receptor-binding B subunits. Here, we have systematically evaluated the comparative adjuvant properties of highly purified recombinant EtxB and CtxB. EtxB was found to be a more potent adjuvant than CtxB, stimulating responses to hen egg lysozyme when the two were coadministered to mice intranasally, as assessed by enhanced serum and secretory antibody titers as well as by stimulation of lymphocyte proliferation in spleen and draining lymph nodes. These results indicate that, although structurally very similar, EtxB and CtxB have strikingly different immunostimulatory properties and should not be considered equivalent as prospective vaccine adjuvants.
Millar
D G
DG
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada L8N 3Z5. dmillar@uhnres.utoronto.ca
Hirst
T R
TR
Snider
D P
DP
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology*; D002772:Cholera Toxin / Q000494:pharmacology*; D004768:Enterotoxins / Q000494:pharmacology*; D029968:Escherichia coli Proteins; D007114:Immunization; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008213:Lymphocyte Activation; D051379:Mice; D008809:Mice, Inbred C3H; D009113:Muramidase / Q000276:immunology; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000494:pharmacology
D000276:Adjuvants, Immunologic; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D021122:Protein Subunits; D011994:Recombinant Proteins; D002772:Cholera Toxin; C027538:heat-labile enterotoxin, E coli; C421864:hen egg lysozyme; D009113:Muramidase