PGG-glucan, a soluble beta-(1,3)-glucan, enhances the oxidative burst response, microbicidal activity, and activates an NF-kappa B-like factor in human PMN: evidence for a glycosphingolipid beta-(1,3)-glucan receptor.
PGG-Glucan, a soluble beta-(1,6)-branched beta-(1,3)-linked glucose homopolymer derived from the cell wall of the yeast Saccharomyces cerevisiae, is an immunomodulator which enhances leukocyte anti-infective activity and enhances myeloid and megakaryocyte progenitor proliferation. Incubation of human whole blood with PGG-Glucan significantly enhanced the oxidative burst response of subsequently isolated blood leukocytes to both soluble and particulate activators in a dose-dependent manner, and increased leukocyte microbicidal activity. No evidence for inflammatory cytokine production was obtained under these conditions. Electrophoretic mobility shift assays demonstrated that PGG-Glucan induced the activation of an NF-kappaB-like nuclear transcription factor in purified human neutrophils. The binding of 3H-PGG-Glucan to human leukocyte membranes was specific, concentration-dependent, saturable, and high affinity (Kd approximately 6 nM). A monoclonal antibody specific to the glycosphingolipid lactosylceramide was able to inhibit activation of the NF-kappaB-like factor by PGG-Glucan, and ligand binding data, including polysaccharide specificity, suggested that the PGG-Glucan binding moiety was lactosylceramide. These results indicate that PGG-Glucan enhances neutrophil anti-microbial functions and that interaction between this beta-glucan and human neutrophils is mediated by the glycosphingolipid lactosylceramide present at the cell surface.
Wakshull
E
E
Department of Biology, Alpha-Beta Technology, Worcester, MA 01605, USA. ewaksh@abti.com
Brunke-Reese
D
D
Lindermuth
J
J
Fisette
L
L
Nathans
R S
RS
Crowley
J J
JJ
Tufts
J C
JC
Zimmerman
J
J
Mackin
W
W
Adams
D S
DS
D000276:Adjuvants, Immunologic / Q000378:metabolism / Q000494:pharmacology*; D015703:Antigens, CD; D001665:Binding Sites; D001770:Blood Bactericidal Activity / Q000187:drug effects*; D002462:Cell Membrane / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood; D004268:DNA-Binding Proteins / Q000502:physiology; D005936:Glucans / Q000378:metabolism / Q000494:pharmacology*; D006028:Glycosphingolipids / Q000378:metabolism*; D006801:Humans; D007790:Lactosylceramides / Q000378:metabolism; D016328:NF-kappa B / Q000502:physiology*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D011971:Receptors, Immunologic / Q000378:metabolism*; D016897:Respiratory Burst / Q000187:drug effects*; D013379:Substrate Specificity; D014316:Tritium; D047071:beta-Glucans
D000276:Adjuvants, Immunologic; D015703:Antigens, CD; D016207:Cytokines; D004268:DNA-Binding Proteins; D005936:Glucans; D006028:Glycosphingolipids; D007790:Lactosylceramides; D016328:NF-kappa B; D011971:Receptors, Immunologic; D047071:beta-Glucans; C045268:beta-glucan receptor; C069894:poly-1-6-glucopyranosyl-1-3-glucopyranose glucan; D014316:Tritium; C009744:CDw17 antigen