COMPARATIVE EFFECT OF C3A AND C5A ON ADHESION MOLECULE EXPRESSION ON NEUTROPHILS AND ENDOTHELIAL-CELLS

Complement activation is known to enhance neutrophil binding to human umbilical vein endothelial cells (HUVECs). Recently, we have shown tha t recombinant human C5a upregulates P-selectin in HUVECs. Unstimulated human neutrophil binding is also increased on C5a stimulated HUVECs. We demonstrate in this report that C5a upregulates CD11b/CD18 in human neutrophils. Also shown is that synthetic C3a(57-77) and an analog 15 amino acid C3a peptide (C3a(15)) neither upregulate CD11b/CD18 nor do the C3a peptides increase P-selectin, ICAM-1 or E-selectin in HUVECs. Thus C5a and not C3a is responsible for early (similar to 30 minutes) neutrophil adhesion to endothelial cells after complement activation.