Neutralization of Bacteriophage ΦX174 by Specific Antiserum

Autor: Bernard U. Bowman, Robert A. Patnode
Rok vydání: 1964
Předmět:
Zdroj: The Journal of Immunology. 92:507-514
ISSN: 1550-6606
0022-1767
DOI: 10.4049/jimmunol.92.4.507
Popis: Summary Three lots of bacteriophage ΦX174 were prepared by different techniques. Lot I was concentrated by dialysis against Carbowax 4000. Further concentration and purification were performed by differential centrifugation. Lot II was purified and concentrated by (NH4)2SO4 precipitation, followed by differential centrifugation. Lot III phage was treated exactly as the lot II phage except that it was further purified by RbC1 equilibrium density gradient ultracentrifugation. Analytical ultracentrifugation studies revealed that the lot II phage was composed of 114 S and 76 S particles and that the lot III phage contained only 113 S virions. The antibody levels of sera from rabbits injected with lot I ΦX174 showed a typical primary response. The levels increase more rapidly and to a greater extent following the second injection of phage. Serum obtained from one rabbit on the 6th day after the second injection of phage was designated S24 and was used for all subsequent neutralization studies. Serum from rabbits injected with filtrate material from a broth culture of the host organism, Escherichia coli strain C, failed to neutralize phage. In neutralization reactions with S24 diluted 2.8 × 104 times and lot I ΦX174 at an initial phage concentration (P0) of between 108 and 105 plaque-formers ml-1, the over-all rate of change of the survivor fractions was not constant for every P0/serum concentration ratio. This fact could not be attributed to reversible neutralization nor to the strain of host bacterium used for assay of surviving phage. With P0 between 6 × 108 and 6 × 105 plaqueformers ml-1, neutralization of lot I ΦX174 by S24 diluted 6 × 104 times obeyed the percentage law, but the neutralization curves were not exponential. When the highly purified lot III ΦX174 was used in neutralization experiments with S24 diluted 6 × 104 times, the percentage law was obeyed when P0 was between 4.08 × 108 and 4.08 × 105 plaque-formers ml-1. In addition, all of the neutralization curves were exponential. The specific rate constant of the ΦX174-S24 system was dependent on the temperature of incubation. The Arrhenius constant was approximately 9600 calories mole-1, corresponding to a Q10 of about 1.8.
Databáze: OpenAIRE
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