In vitro effect of a ribosomal extract of klebsiella pneumoniae on normal human polymorphonuclear neutrophil functions

The in vitro effect of a ribosomal extract of Klebsiella pneumoniae on polymorphonuclear leukocytes (PMNs) from 22 healthy subjects was assessed. With the concentrations used (2, 4 and 6 μg/10 6 cells), no significant modification of the superoxide anion production was observed. While random migration was only slightly reduced, the chemotactic response of PMNs toward zymosan activated serum was significantly decreased with the three concentrations of the ribosomal extract. The inhibitory effect observed in the chemotactic activity was not due to an alteration of the viability of PMNs, but could have been caused by the presence of endotoxins not removed during the ribosomal extract preparation. It is suggested that the beneficial effect of this ribosomal preparation on defense mechanisms is not related to a direct action of the drug on normal polymorphonuclear leukocytes.