BINDING OF COMPLEMENT C3 TO KLEBSIELLA-PNEUMONIAE TREATED WITH SUB-MIC CEFODIZIME AND CHEMILUMINESCENCE RESPONSE OF HUMAN POLYMORPHONUCLEARLEUKOCYTES

The binding of complement C3 to the cell surface of Klebsiella pneumon iae exposed to human serum complement after treatment with or without sub-MIC of antibiotics was examined by double diffusion immunoprecipit ation against anti-human complement C3, and the production of oxygen-d erived radicals by human polymorphonuclear leukocytes stimulated by co mplement-opsonized K. pneumoniae after treatment with or without sub-M IC of antibiotics was measured using the chemiluminescence (CL) assay. Complement C3 bound to the cell surface of K. pneumoniae treated with cefodizime was detected after exposure to human serum complement, The CL response induced by complement-opsonized bacteria after treatment with cefodizime was much higher than the response induced by nontreate d bacteria or complement-opsonized bacteria after treatment with other antibiotics, These findings indicate that treatment with sub-MIC cefo dizime make K. pneumoniae more susceptible to opsonization by compleme nt and promotes the specific phagocytosis mediated by complement recep tors.