Activation of human basophils by Staphylococcus aureus Cowan I. II. Alternative F(ab')-mediated mechanism.
We investigated the capacity of Staphylococcus aureus Cowan I (Cowan Staph A+) and Staphylococcus aureus Wood 46 (Wood Staph A-) to induce histamine release from human basophils in vitro. Cowan Staph A+ (3 X 10(6) to 3 X 10(8)/ml), which synthesizes protein A (Staph A), stimulated the release of histamine from basophils, whereas Wood Staph A- (3 X 10(6) to 3 X 10(9)/ml), which does not synthesize Staph A, did not induce histamine secretion. Soluble Staph A (10(-3) to 10 micrograms/ml) also induced histamine secretion from human basophils, Hyperiodination of Staph A, which destroys over 90% of the original Fc reactivity without altering the Fab binding site, did not alter this protein's ability to induce histamine release. The stimulating effect of Staph A was suppressed by preincubation with human polyclonal IgG and a human monoclonal IgM, which have F(ab')-Staph A reactivity. In contrast, rabbit IgG and a human monoclonal IgM possessing only Fc-Staph A reactivity did not inhibit Staph A activity. Preincubation with Staph A or Cowan Staph A+ resulted in complete cross-desensitization to a subsequent challenge with homologous and heterologous stimuli. These results indicate that Staph A and Cowan Staph A+ activate human basophils by interacting with the F(ab')2 region of IgE and/or IgG present on the cell surface.
G
G
Marone
M
M
Tamburini
M G
MG
Giudizi
R
R
Biagiotti
F
F
Almerigogna
S
S
Romagnani
D001491:Basophils / Q000276:immunology* / Q000378:metabolism; D001666:Binding Sites, Antibody; D006636:Histamine Release; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007140:Immunoglobulin Fab Fragments / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D013205:Staphylococcal Protein A / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*
D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D013205:Staphylococcal Protein A; D007073:Immunoglobulin E