Protective effects of a supernatant factor from Salmonella typhimurium on Salmonella typhimurium infection of inbred mice

Abstract

A supernatant factor prepared from 48-h cultures of Salmonella typhimurium has been used to immunize mice against subsequent challenge with normally lethal doses of S. typhimurium. The mouse strains used, C57BL and BALB/c, were sensitive to S. typhimurium with 50% lethal doses of less than 50 organisms. Two doses of supernatant factor, given intraperitoneally 20 days apart, protected mice against a subcutaneous challenge dose 10 days later of 100 50% lethal doses of S. typhimurium, resulting in 50 to 80% survival. The viable counts were reduced initially in organs of immunized mice compared with controls, and the multiplication of bacteria was delayed, although the final levels found in the organs would normally have been lethal. Protection obtained was specific for S. typhimurium in that no increased survival was shown after Salmonella enteritidis challenge of immunized mice. Although lipopolysaccharide was demonstrated in the supernatant factor, lipopolysaccharide alone did not protect challenged mice. Supernatant factor produced delayed-type hypersensitivity reactions in mice sensitized with nonlethal doses of Salmonella. The nature of the active factor, found to be partially protein, has yet to be elucidated.

The protein‐lipopolysaccharide complex extracted with trichloracetic acid from Salmonella typhimurium effective in protection of mice against S. typhimurium infection

“…There was no immediate 4 h increase in footpad size. These results contrast with the high 4 h response and lack of DTH reaction in mice challenged with LPS alone (Plant, Glynn & Wilson 1978).…”

“…The immunogens were prepared at the required concentrations in 0.2 ml saline and intraperitoneally injected (i.p.i.). The challenge dose of I O3 S. typhimuriurn was subcutaneously injected (s.c.i.j on day 3 1 (Plant, Glynn & Wilson 1978, Plant, Glynn & Valtonen 1980. The dose was equivalent to > 100 LDso for BALB/c mice (Plant & Glynn 1974).…”

“…Haemagglutination gave more sensitive estimations of 0-antibody titres in the sera. Sheep red blood cells (SRBC) were coated with S. typhimurium LPS B and used at concentrations of 1% to detect haemagglutinating antibodies in the sera (Plant, Glynn & Wilson 1978).…”

“…This is the third in a series of papers (Plant, Glynn & Wilson 1978, Plant, Glynn & Valtonen 1980 defining the protective properties of extracted material from S. typhimurium cultures against S. typhimurium infections in mice. A supernatant factor (SF) prepared from 48-h bacterial growth in a simple salts medium protected normally TR I CH LOR A CETI c -A C I D EXTRA CTI O N or: LPS ( TC A -L PS) The LPS was extracted from cultures of S .…”

Delayed Hypersensitivity in Murine Salmonellosis: Specificity of Footpad Reaction in Mice Infected with Rough Mutants of Salmonella typhimurium

“…Cell-mediated protection against salmonella infection does not depend on the surface o antigenic components of the organisms (12,22). Manifestation of DTH is found 167 to be present in mice immunized with protein-rich bacterial fractions from S. typhimurium (19,21). However, the specificity of DTH in salmonellosis is not yet defined.…”