[Oral infection by Y. enterocolitica 0:8. Studies of immunization in a murine model]

The evaluation and mechanism of protection against Y. enterocolitica O:8 using different immunization schedules. We immunize 3 groups of 20 mice each against an oral lethal dose of Y. enterocolitica O:8 using: 1) whole cells, 2) hyperimmune sera, and 3) LPS and common antigen. Animals immunized using whole live cells that produce common antigen (O:3 +V and IP614) developed the highest degree of protection, with an overall survival rate of 70% and 60% respectively. Similar results were obtained using animals immunized with sera. Animals immunized using LPS and common antigen also were able to control the replication of the infecting strain. Common antigen and antibodies against it did not inhibit adherence not bacterial invasion. However, it seems to be an important protecting factor, that controls the bacterial replication in intestinal lymph tissue. The exact mechanism is currently unknown.