Immune response against adhesins of enteroaggregative Escherichia coli immunized by three different vaccination strategies (DNA/DNA, Protein/Protein, and DNA/Protein) in mice.

Molecular Biology Unit, Pasteur Institute of Iran, Tehran 13164, Iran.

Enteroaggregative Escherichia coli (EAEC) are an increasingly recognized enteric pathogen. It is a cause of both acute and persistent diarrhoea among children, adults and HIV-infected persons, in both developing and developed countries. The aggregative adherence of EAEC is due to the presence of aggregative adherence fimbriaes (AAFs). To elucidate the possible protective role of these adhesins in diarrheagenic E. coli with DNA immunization approach, Balb/c mice were immunized with three different modes of vaccination, i.e. DNA/DNA, DNA/Protein, or Protein/Protein of Aggregative Adherence Factors, AAF/I or AAF/II of enteroaggregative Escherichia coli (EAEC), respectively. Overall, AAF/I and AAF/II in DNA/DNA mode could not induce the immune response. However, the DNA/Protein immunization of AAF/I significantly (P<0.05) induced total IgG level, and in the case of Protein/Protein approach, the induction of immune system was more significant (P<0.02). The DNA/Protein regimen of AAF/II induced total IgG significantly (P<0.03). But in the case of Protein/Protein immunization, the induced response was not significant. These preliminary data revealed that as an antigen, these two adhesins behave in a different manner, although AAF/I and AAF/II are known adhesins of EAEC with putatively similar functions.

PMID: 19022502 [PubMed - as supplied by publisher]