Opsonic effect of normal and infected human urine on phagocytosis of Escherichia coli and yeasts by neutrophils.

The opsonic effect of urine from normal adults and patients with acute cystitis on phagocytosis of yeast and E. coli by purified human neutrophils was investigated. Urine with an osmotic pressure between 200 and 500 mOsm./kg. was the most effective as an opsonic buffer in either phagocytosis of yeast or E. coli by PMN. However, those with an osmotic pressure greater than 500 mOsm./kg. or less than 200 mOsm./kg. were rather suppressive to phagocytosis by PMN. Patient's urine exhibited a more potent opsonic effect on phagocytosis of either bacteria when compared with that of normal urine with a similar osmotic pressure. Heat inactivation gave no effect on the potent opsonic activity of patient's urine, suggesting that complement may not be working in these phagocytosis systems or that the test urine may originally contain no complement. However, immunoelectrophoretic survey of test urine and addition of serum proteins into the urine suggest the possibility that certain serum derived urine proteins other than complement may play an opsonic role in phagocytosis by PMN in the patient's urine, although the factors have not been determined.