scholarly journals COMPLEMENT-DEPENDENT PLATELET INJURY BY STAPHYLOCOCCAL PROTEIN A

1972 ◽  
Vol 136 (1) ◽  
pp. 68-80 ◽  
Author(s):  
Jacek Hawiger ◽  
Samuel R. Marney ◽  
Daniel G. Colley ◽  
Roger M. Des Prez
Keyword(s):  
Cell Wall ◽  
Complement Fixation ◽  
Protein A ◽  
Staphylococcal Infection ◽  
Rabbit Platelet ◽  
Small Range ◽  
Staphylococcal Protein A ◽  
Common Component ◽  
Staphylococcal Protein ◽  
Biologic Property

A new example of complement-mediated platelet injury has been described. Staphylococcal protein A (SPA) causes rabbit platelet injury as manifested by release of platelet 5-hydroxytryptamine (5HT). This reaction is complement-dependent and occurs over a very small range of SPA concentration, larger amounts being inhibitory. Complement fixation by SPA demonstrates the same narrow SPA concentration requirement whereas precipitation of IgG by SPA is roughly proportional to SPA concentration over a wide concentration range. The reaction can be separated into a sensitization step which requires SPA and plasma but not complement, and a release step which does require complement. Complement-mediated platelet damage induced by SPA is a new biologic property of this common component of the cell wall of pathogenic staphylococci which may contribute to the development of inflammatory and thromboembolic reactions complicating intravascular staphylococcal infection.

scholarly journals Region X, the cell-wall-attachment part of staphylococcal protein A

1984 ◽  
Vol 138 (2) ◽  
pp. 413-420 ◽  
Author(s):  
Bengt GUSS ◽  
Mathias UHLEN ◽  
Bjorn NILSSON ◽  
Martin LINDBERG ◽  
John SJOQUIST ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein A ◽  
Staphylococcal Protein A ◽  
Staphylococcal Protein

scholarly journals The YSIRK-G/S Motif of Staphylococcal Protein A and Its Role in Efficiency of Signal Peptide Processing

2003 ◽  
Vol 185 (9) ◽  
pp. 2910-2919 ◽  
Author(s):  
Taeok Bae ◽  
Olaf Schneewind
Keyword(s):  
Cell Wall ◽  
Signal Peptide ◽  
Protein A ◽  
Surface Proteins ◽  
Signal Peptides ◽  
Staphylococcal Protein A ◽  
Gram Positive ◽  
Peptide Processing ◽  
Staphylococcal Protein ◽  
Sorting Signal

ABSTRACT Many surface proteins of pathogenic gram-positive bacteria are linked to the cell wall envelope by a mechanism requiring a C-terminal sorting signal with an LPXTG motif. Surface proteins of Streptococcus pneumoniae harbor another motif, YSIRK-G/S, which is positioned within signal peptides. The signal peptides of some, but not all, of the 20 surface proteins of Staphylococcus aureus carry a YSIRK-G/S motif, whereas those of surface proteins of Listeria monocytogenes and Bacillus anthracis do not. To determine whether the YSIRK-G/S motif is required for the secretion or cell wall anchoring of surface proteins, we analyzed variants of staphylococcal protein A, an immunoglobulin binding protein with an LPXTG sorting signal. Deletion of the YSIR sequence or replacement of G or S significantly reduced the rate of signal peptide processing of protein A precursors. In contrast, cell wall anchoring or the functional display of protein A was not affected. The fusion of cell wall sorting signals to reporter proteins bearing N-terminal signal peptides with or without the YSIRK-G/S motif resulted in hybrid proteins that were anchored in a manner similar to that of wild-type protein A. The requirement of the YSIRK-G/S motif for efficient secretion implies the existence of a specialized mode of substrate recognition by the secretion pathway of gram-positive cocci. It seems, however, that this mechanism is not essential for surface protein anchoring to the cell wall envelope.

scholarly journals Quantification of platelet-bound IgG by 125I-Staphylococcal protein A in immune thrombocytopenic purpura and other thrombocytopenic disorders

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 154-161 ◽  
Author(s):  
GM Shaw ◽  
J Axelson ◽  
JG Maglott ◽  
AF LoBuglio
Keyword(s):  
Immune Thrombocytopenic Purpura ◽  
Protein A ◽  
Normal Subjects ◽  
Unknown Etiology ◽  
Staphylococcal Protein A ◽  
Thrombocytopenic Purpura ◽  
Clinical Criteria ◽  
Staphylococcal Protein ◽  
Wide Range ◽  
Immune Hemolytic Anemia

Abstract In this report we describe the use of an 125I-Staphylococcal protein A (SPA) assay to measure platelet-bound IgG in the evaluation of 62 thrombocytopenic patients. Platelets from 150 normal subjects were found to bind 146 +/- 112 molecules of SPA per platelet (mean +/- 2 SD). Nineteen of 20 patients with untreated immune thrombocytopenia had platelet IgG values above this range, with 15 of 20 having values above 1,000 molecules of SPA per platelet. Patients with immune thrombocytopenic purpura by clinical criteria, but who had failed conventional therapy (corticosteroids or splenectomy), had a wide range of platelet IgG levels: 4 of 20 had normal values, 6 of 20 had minimally elevated levels in the range seen with nonimmune thrombocytopenia, and 10 of 20 had much higher values. Fifteen patients with thrombocytopenia of apparent nonimmune origin and 7 others with chronic stable thrombocytopenia of unknown etiology were found to have platelet IgG levels within or only slightly above the normal range. Because of its simplicity, accuracy, and clinical correlation, the 125I- SPA assay provides an important new approach for studying platelet IgG in thrombocytopenic states. The data obtained with this technique are similar to those found in immune hemolytic anemia and suggest that the platelet-bound IgG so measured has pathophysiologic relevance in immune thrombocytopenic purpura.

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