Survival Of Immunized Mice Research Articles

Immunization against Pseudomonas aeruginosa: The effects of serotype and virulence in mouse protection tests

Mouse protection tests were performed with formol killed whole cell vaccines prepared from 28 strains of Pseudomonas aeruginosa . One week after a single subcutaneous injection the mice were challenged intraperitoneally with live bacteria in 4·5% gastric mucin and median lethal dose (LD 50 ) values for immunized and un-immunized mice were compared. Most strains gave good protection against themselves as challenge strain (autologous tests) and also against other strains of the same Habs serotype (homologous tests). In general the protection was inferior or absent when the challenge strain differed in serotype from the vaccine strain. Vaccines derived from highly virulent strains seldom gave better protection than vaccines from less virulent strains. On the other hand, the survival of immunized mice was better after homologous challenge with virulent strains than with the same number of LD 50 units of less virulent strains.

Cortisone and mortality in mouse typhoid. III. Effect of natural and acquired immunity.

SummarySeven mouse strains which were selected for the wide range in their natural resistance to S. typhimurium were used. Typhoid resistance of every strain was decreased when 1 mg cortisone was given one day before typhoid inoculation. The difference between survival of cortisone treated mice and that of controls was evident at an earlier time in the genetically susceptible strains than in resistant strains. A single injection of 5 mg cortisone which reduced survival of non-immunized mice from 100% to 0% had no significant effect on survival of immunized mice.