Nonspecific resistance against infection with Salmonella typhi and Salmonella typhimurium induced in mice by cord factor (trehalose-6,6'-dimycolate) and its analogues.

Mice pretreated intraperitoneally with trehalose-6,6'-dimycolate (cord factor) were protected against an intraperitoneal challenge with Salmonella typhi strain Ty2 or Salmonella typhimurium strain SR 11. The nonspecific resistance to S. typhi and S. typhimurium was still detectable 7 and 14 days, respectively, after administration of cord factor. The effect of cord factor was local. Synthetic analogues of cord factor--trehalose-6,6'-dipalmitate and trehalose monopalmitate--also induced nonspecific resistance to the above virulent bacteria. The results are discussed.