Complement activation is variably affected by fibronectin preparations obtained through different procedures.
Human plasma fibronectin (FN) containing preparations (FNCP) were prepared by means of gelatin-affinity chromatography of normal plasma cryoprecipitate (FNCP-a), and by affinity chromatography of cryoprecipitate on a rabbit anti-human FN antiserum Sepharose column (FNCP-b) or of normal citrated plasma (FNCP-c). These preparations were then tested for their ability to influence certain complement (C')-dependent polymorphonuclear phagocyte activities. FNCP-a consistently inhibited humoral chemotaxis, whereas FNCP-b and -c did not. Measurement of C' activation by the C3 conversion assay revealed that only FNCP-a displayed inhibitory activity on classical and alternative pathways. Ouchterlony and immunoelectrophoretic analyses indicated substantial identity of all FNCPs. FNCP-a contained a consistent amount of lower MW contaminants (between 40 and 60 KD) which were shown not to be immunologically related to FN by Western blot analysis. Immunoblotting also revealed a single band in FNCP-a (MW approx. 210 KD) instead of the anticipated two bands which were evident in the other FNCPs. Thus, a slight modification of the FN molecule and/or the presence of low MW contaminants in the gelatin-purified preparation seem able to induce inhibitory effects on C'-dependent polymorphonuclear phagocytic activities.
Fattorossi
A
A
Department of Allergy and Clinical Immunology, University of Rome La Sapienza, Italy.
Le Moli
S
S
Pontesilli
O
O
Aiuti
A
A
Nisini
R
R
Galli
E
E
Carbonari
M
M
D'Amelio
R
R
D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D003167:Complement Activation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005353:Fibronectins / Q000138:chemical synthesis / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects; D010587:Phagocytosis / Q000187:drug effects
D005353:Fibronectins