Human plasma fibronectin effect on serum-mediated uptake of Pseudomonas aeruginosa PA 1348A by human granulocytes.

The effect of human plasma fibronectin on human granulocyte (PMN) phagocytosis of one strain of Pseudomonas aeruginosa (PA 1348A) was examined in a previously defined optimal phagocytic assay. Normal and fibronectin-deficient serum demonstrated similar rates of bacterial uptake by PMNs. Complement depletion of both sera inhibited phagocytosis. Addition of purified fibronectin did not alter phagocytosis. These findings strongly support the conclusion that fibronectin neither promotes nor inhibits opsonization for phagocytosis of this strain of P. aeruginosa.