Figure 3: L91 fails to evoke antibody response upon immunization. The presence or absence of anti-peptide Abs was examined in the serum of mice immunized with L91 or placebo. M1, M2, M3 represent the data from individual mice. The level of OD indicates that the Ab is negative in serum of L91 vaccinated mice. The data (OD) of the bar diagram are represented as the mean ± SD (three independent experiments, **P <0.003).