Human platelet activation by C3a and C3a des-arg. Academic Article uri icon

Overview

abstract

  • C3a liberated from C3 by treatment with C3 convertase (or by trypsin) induced aggregation of gel-filtered human platelets and stimulated serotonin release. At concentrations of 10(-10) M to 8 X 10(-12) M, C3a induced aggregation when added alone to platelets. However, at lower concentrations (2 X 10(-12) M) C3a did not aggregate platelets directly but exhibited highly significant synergism (two-way analysis of variance P less than 0.0001) with ADP in mediating platelet aggregation and release of serotonin. Removal of the C-terminus arginine from C3a abolished anaphylotoxin activity but did not affect the platelet-stimulating activity of the peptide. C3a and C3a des-arg were equally reactive in mediating platelet aggregation and release of serotonin. Further C3a and C3a des-arg exhibited synergism with ADP of equal significance in both aggregation and the release reaction. The concentrations of C3a required for the platelet-stimulating activity involve relatively small number of molecules per platelet (4,000-10,000 for the synergistic reaction with ADP). These data suggest the possibility of a C3a (C3a des-arg) receptor on human platelets. This premise is strengthened by the demonstration ultrastructurally of C3a on the platelet membrane subsequent to C3a stimulation.

publication date

  • August 1, 1983

Research

keywords

  • Blood Platelets
  • Complement C3
  • Complement C5
  • Platelet Aggregation

Identity

PubMed Central ID

  • PMC2187348

Scopus Document Identifier

  • 0020613041

Digital Object Identifier (DOI)

  • 10.1084/jem.158.2.603

PubMed ID

  • 6604123

Additional Document Info

volume

  • 158

issue

  • 2