The bactericidal antibody test depends on the presence of sufficient complement, magnesium ions, and specific antibody to produce killing of certain gram negative bacilli. This study was undertaken to demonstrate whether or not Salmonella pullorum is an organism which is susceptible to this killing action.
Different amounts of test serum containing antibody, constant amounts of complement and magnesium saline diluent were placed together and held in a 37°C water bath for a one hour reaction time. During this interval, the antibody-complement system was given an opportunity to kill the susceptible bacteria. Then, a constant volume of nutrient broth was added to each tube to terminate the killing action and to provide nutrients for the surviving bacteria to multiply as they were incubated at 37°C for a growth time.
At intervals of four and five hours incubation at 37°C the density of growth in each test and control tube was measured using a photoelectric colorimeter. During this time the bacteria were in the logarithmic phase of growth and the optical density was directly proportional to the number of bacteria surviving the original inoculum. Using this information it was possible to measure the apparent degree of killing produced by the test serum during the reaction time and to quantitatively determine its antibody titer by calculating that amount of serum producing a 50% survival end point.
Immunization of three rabbits was conducted in order to demonstrate the effectiveness of the bactericidal system using Salmonella pullorum. Results indicated that Salmonella pullorum was highly susceptible to the killing action of the antibody system.
Bactericidal assays and agglutination tests were performed on the rabbit sera at regular intervals during the immunization program and the antibody titers compared. Results indicated that the bactericidal antibody test was indeed a very sensitive test for Salmonella pullorum antibody detection with maximum bactericidal titers of 17, 540, 51, 720, 15, 960 resulting from the sera of rabbits #1, #2, and #3 as compared to maximum agglutination titers of 256, 8, 192, and Thus, for rabbits 1,024. #1, #2, and #3 the greatest bactericidal antibody titer of the serum was 69, 6, and 16 times greater than the corresponding top agglutinin titer.
Charles E. Winter
Donald M. Brown
Leonard R. Bullas
Raymond A. Mortensen
Albert L. Olson
Master of Science (MS)
Year Degree Awarded
Date (Title Page)
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This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Rahn, Alice Margaret, "Evaluation of the Photometric Assay Method to Quantitate the Bactericidal Action of Normal and Immune Rabbit Sera on SALMONELLA PULLORUM" (1963). Loma Linda University Electronic Theses, Dissertations & Projects. 810.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives