Unstimulated mouse peritoneal macrophages attached to a glass substratum responded to activated human factor B (Bb) of the properdin system but not to native factor B with rapid spreading and a concomitant increase in their apparent surface area. Excellent correlation of the distribution of Bb protein and cell-spreading activity was found upon purification of Bb by ion-exchange and molecular seive chromatography and alkaline polyacrylamide gel electrophoresis. 1.6 microgram of purified Bb was sufficient to induce spreading in 50% of 5 x 10(4) glass attached macrophages within 1-2 h at 37 degrees C. Treatment of Bb with di-isopropyl-fluorophosphate indicated that the intact catalytic site of the serine-proteinase Bb was required for the initiation of macrophage spreading. The involvement of factor B in the induction of rapid cell spreading could also be indirectly demonstrated in an autologous system in which F(ab')2 fragments of an antiserum to mouse B prevented mouse macrophages from spreading in response to complement-activated mouse serum. These experiments suggest a role for factor B and the alternative pathway of complement fixation in the localization of mononuclear phagocytes to areas of inflammation.
Article| February 01 1979
The induction of macrophage spreading by factor B of the properdin system.
Z A Cohn
Online Issn: 1540-9538
Print Issn: 0022-1007
J Exp Med (1979) 149 (2): 372–386.
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O Götze, C Bianco, Z A Cohn; The induction of macrophage spreading by factor B of the properdin system.. J Exp Med 1 February 1979; 149 (2): 372–386. doi: https://doi.org/10.1084/jem.149.2.372
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