FIG 4.

Relationship between LigA7-13 antibody level and survival. LigA IgG antibody levels after two (A and B) and four (C and D) weeks of immunization were analyzed depending on the immunization and survival status of the animals. After both 2 and 4 weeks of oral immunization, LigA7-13-immunized hamsters that survived (avoided endpoint criteria) had higher antibody levels than either immunized hamsters that met endpoint criteria sooner (sacrificed) or control-immunized hamsters. LigA7-13 antibody levels represent the mean of ELISAs performed in triplicate. The number of asterisks indicates the significance level: **, P < 0.01; ***, P < 0.001. The letters “ns” indicate nonsignificance (P > 0.05). The dotted line shows the critical limit, defined as the value of the mean level of the control-immunized group plus 1.65 SD (experiment 1, 0.236; experiment 2, 0.427).