Demonstration of peptidoglycan-binding sites on lymphocytes and macrophages by photoaffinity cross-linking.
One dominant binding site (70 kDa 6.5 pI protein) for bacterial cell wall peptidoglycan (PGN), a macrophage activator and polyclonal B cell mitogen, was demonstrated on mouse B and T lymphocytes and macrophages by photoaffinity cross-linking and two-dimensional polyacrylamide gel electrophoresis. This binding site was not present on erythrocytes. The binding was specific for polymeric PGN and was competitively inhibited by unlabeled PGN with IC50 = 48 micrograms/ml (0.38 microM). The binding was partially inhibited by O-acetylated PGN monomers (IC50 = 469 micrograms/ml, 521 microM), dextran sulfate (IC50 = 1024 micrograms/ml, 124 microM), and (GlcNAc)3 (IC50 = 6.6 mg/ml, 10 mM), and was not inhibited by non-O-acetylated PGN monomers and dimers, muramyl dipeptide, PGN pentapeptide, GlcNAc, teichoic acid, protein A, and gelatin. The cell surface location of the 70-kDa PGN-binding protein was indicated by the ability of PGN to bind to this protein in intact metabolically inactive cells (at 4 degrees C and in the presence of 0.1% NaN3) and by the ability to extract the 70-kDa PGN-binding protein from viable B lymphocytes by noncytotoxic concentration of n-octyl-beta-D-glucopyranoside.
Dziarski
R
R
Northwest Center for Medical Education, Indiana University School of Medicine, Gary 46408.
D000345:Affinity Labels; D000818:Animals; D001667:Binding, Competitive; D003432:Cross-Linking Reagents; D015180:Electrophoresis, Gel, Two-Dimensional; D008214:Lymphocytes / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D010457:Peptidoglycan / Q000378:metabolism*; D010777:Photochemistry
D000345:Affinity Labels; D003432:Cross-Linking Reagents; D010457:Peptidoglycan