Antibody response in BALB/c mice following immunization with bacterial vaccines prepared in test adjuvants. Control mice were either unimmunized or immunized with vaccines in PBS with no adjuvant. The ΔOD490 values were obtained by subtracting absorbance due to normal mouse sera from the experimental ones. Polyclonal antisera obtained from E. coli or S. aureus were evaluated at 1:200 dilutions by ELISA. The results represent the average of three separate experiments (n = 4 mice in each three experiments) ± SEM. A. Anti-E. coli Ab response, B. Anti-S. aureus Ab response. Significant increase of antibody response was observed in the sera of mice after the third immunization (P < 0.05).