[Preventive activity of an artificial antigen possessing the serological specificity of Salmonella O-factor 3]

3-0 [4-0 (beta-D-mannopyranosyl)-alpha-L-rhamnopyranosyl]-beta-allyl-D- galactopyranoside with acrylamide, a new synthetic antigen possessing the narrow specificity of Salmonella O-factor 3, was found to protect mice, when introduced into the animals by multiple intraperitoneal injections, from the action of the live culture of Salmonella anatum and the toxic doses of its endotoxin.