Normal Serum Cytotoxicity for P32-Labeled Smooth Enterobacteriaceae III. Isolation of a γG Normal Antibody and Characterization of Other Serum Factors Causing P32 Loss

摘要

Spitznagel, John K. (University of North Carolina School of Medicine, Chapel Hill). Normal serum cytotoxicity for P³²-labeled smooth Enterobacteriaceae. III. Isolation of a γG normal antibody and characterization of other serum factors causing P³² loss. J. Bacteriol. >91:401–408. 1966.—Gram-negative bacteria lost metabolically incorporated P³² when suspended in serum only if the serum contained heat-labile in addition to heat-stable factors. Gram-positive bacteria labeled with P³² and included for comparison lost P³² in heat-inactivated as well as in fresh normal serum. Further investigation of gram-negative bacteria showed that a smooth Escherichia coli (O117:H27) lost P³² only if suspended in serum containing complement fractions C′1, C′2, C′3, and C′4 “normal” antibody and lysozyme. The normal antibody was recovered by absorption on and subsequent elution from E. coli O117:H27 cell walls. Immunoelectrophoresis showed that it was a γG-globulin. Its P³²-releasing activity was destroyed by 2-mercaptoethanol. Lysozyme was found to potentiate the P³²-releasing action of normal antibody plus complement. Evidence was obtained suggesting that β1C globulin was the component absorbed to zymosan during serum absorption at 15 C. Reduction of the β1C level evidently upsets an important balance that exists in normal serum among complement, antibody, and lysozyme. This balance is essential for maximal P³² release from labeled bacteria, or possibly for a maximal antibacterial effect from normal serum. The possible relationships of bactericidal, bacteriolytic, and opsonic action of normal serum are discussed.