KILLING OF THE S-FORM AND RE-FORM OF SALMONELLA-MINNESOTA VIA THE CLASSICAL PATHWAY OF COMPLEMENT ACTIVATION IN GUINEA-PIG AND HUMAN-SERA

  • 1 January 1980
    • journal article
    • research article
    • Vol. 40  (4) , 547-556
Abstract
The S (wildtype) and Re form (heptose-deficient, core-defective mutant) of S. minnesota were killed by treatment with normal guinea-pig serum (GPS). Using C[complement component 4]4-deficient GPS and serum containing 0.02 M ethyleneglycol-bis-(.beta.-aminoethylether)-tetraacetic acid [EGTA] and 0.02 M MgCl2 (EGTA-Mg2+) a reduced killing rate was observed. In normal GPS diluted 1:10 containing 0.02 M EGTA-Mg2+ or in C4-deficient GPS diluted 1:10 no killing occurred, whereas the same serum dilution without EGTA-Mg2+ showed a strong bactericidal effect indicating a dependency upon C4 and Ca2+. In contrast to normal human serum (NHS) no killing occurred in a selective complete Clq-deficient human serum. The bactericidal effect could be restored by addition of highly purified Clq; this is a further indication for a dependency upon the classical pathway of C activation. The C-dependent bactericidal activity was totally abolished when phosphate buffer was used, partially reduced in the presence of veronal-buffered saline (VBS), and not affected by tris-(hydroxymethyl)-aminomethane(Tris) or thioglycollate-buffered system. EGTA-Mg2+ alone slightly reduced the growth rate of the bacteria whereas EDTA had a bacteriostatic effect on the S-form. The inhibition of the growth of the Re-form by EDTA was amplified by the addition of serum. Pre-incubation of bacteria with serum for absorption of antibodies did not increase the killing rate of such pre-treated bacteria excluding an antibody-mediated bactericidal reaction. Pre-treatment of the bacteria with GPS at 0.degree. C reduced the serum sensitivity of both types of bacteria.