Comparative study of the effects of cefodizime and HBW 538 in potentiating the production of reactive oxygen species by human polymorphonuclear leukocytes.

The immunomodulatory activity of cefodizime (CDZM), an aminothiazolylcephalosporin, was compared to that of HBW 538, a derivative of the CDZM side chain at position 3 (the mercaptothiazolyl group) in respect to the production of reactive oxygen species (ROS) by human whole blood and polymorphonuclear leukocytes (PMN) in vitro. Ten-fold diluted whole blood and PMN from healthy individuals were incubated with CDZM or HBW 538 alone at the concentrations of 1, 10, or 100 micrograms/ml, or CDZM or HBW 538 at 100 micrograms/ml in combination with tumor necrosis factor-alpha (TNF-alpha) at 100 U/ml or lipopolysaccharide (LPS) at 1 microgram/ml. The production of ROS was measured by a chemiluminescence (CL) assay in which luminol was added to a mixture and after which the PMN or whole blood were stimulated with nonopsonized zymosan or phorbol myristate acetate. The following results were obtained: (1) The CL responses of whole blood and PMN were slightly but not significantly enhanced by CDZM at 100 micrograms/ml, whereas both CL responses were significantly enhanced by exposure to HBW 538 at 10 and 100 micrograms/ml. (2) The enhanced PMN CL response which followed priming with TNF-alpha or LPS was not augmented by CDZM but was significantly augmented by HBW 538. These results indicate that the ability of the HBW 538 molecule to enhance the production of ROS by stimulated PMN and to act agonistically with TNF-alpha or LPS is abrogated when HBW 538 is part of the CDZM molecule.(ABSTRACT TRUNCATED AT 250 WORDS)