Evaluation of immunogenicity of anti-diarrhea vaccine based on Escherichia coli O157and the influence of the use of adjuvants on their efficacy

Enterohemorrhagic Escherichia coli is one of the major reasons for the bacterial diarrhea. Despite the vast development, there is still no comprehensive treatment for this infection. Vaccine development is the first strategy against bacterial resistance. Due to the pathogenicity of Escherichia coli, the present study was aimed to investigate the role of different adjuvants for vaccination against this bacteria.

The bacteria were cultured and inactivated by formaldehyde for antigen preparation and injection into the mice. Female Balb/c mice were injected subcutaneously with four different bacterial groups including, bacteria with alum adjuvant (AO), montanide adjuvant (MO), non-adjuvant bacteria (O) and control group. Following, the reminder dose was injected after 14 days and blood samples were collected during 7 weeks. The Elisa test was used for evaluation of antibody titer. 28 days after post immunization, the mice were challenged and were evaluated for 72 h. Statistical analysis was accomplished using ANOVA and SPSS software.

The results suggested that while the highest antibody titer was obtained for the AO group, but the MO group has more antibody titer in the first month. Also, challenge results exposed that the AO group protected 100 % of the challenge group mice.

consequently, the produced antibody of the alum adjuvant keep higher the animal’s immune system for a longer period. Since vaccine design to prevent infectious diseases requires effective antigen delivery system, this study could be a new strategy to produce the E. Coli O157:H7 vaccine.