Construction of a non-toxigenic Escherichia coli oral vaccine strain expressing large amounts of CS6 and inducing strong intestinal and serum anti-CS6 antibody responses in mice.

• Coli surface antigen 6 (CS6) is one of the most prevalent non-fimbrial colonization factors (CFs) of enterotoxigenic Escherichia coli (ETEC) bacteria, which are the most common cause of diarrhea among infants and children in developing countries. Since immune protection against ETEC is mainly mediated by locally produced IgA antibodies in the gut, much effort is focused on the development of an oral CF-based vaccine. Previous work has described the preparation of candidate E. coli vaccine strains expressing immunogenic amounts of fimbrial CF antigens such as CFA/I and CS2, which are retained after formalin treatment. However, attempts to generate E. coli expressing immunogenic amounts of CS6 and to preserve the immunological activity of the CS6 protein in a killed whole-cell vaccine have failed until now. Here we describe the construction of a recombinant non-toxigenic E. coli strain, with thyA as a non-antibiotic-based selection, which expresses large amounts of CS6 antigen on the bacterial surface, and show that phenol inactivation of the bacteria does not destroy the CS6 antigen properties. Oral immunization of mice with such phenol-killed CS6 over-expressing E. coli bacteria induced strong fecal and intestinal IgA and serum IgG+IgM antibody responses to CS6 that exceeded the responses induced by an ETEC reference strain naturally expressing CS6 and previously used as a vaccine strain. Our data indicate that the described phenol-inactivated non-toxigenic and CS6 over-expressing E. coli strain may be a useful component in an oral ETEC vaccine.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Microbiology in the medical area (hsv//eng)

Nyckelord

Administration

Oral

Animals

Antibodies

Bacterial

blood

Antibody Formation

Antigens

Bacterial

biosynthesis

genetics

immunology

Escherichia coli

genetics

immunology

metabolism

Escherichia coli Infections

immunology

prevention & control

Escherichia coli Proteins

biosynthesis

genetics

immunology

Escherichia coli Vaccines

immunology

Female

Formaldehyde

Genetic Vectors

Immunity

Mucosal

Immunoglobulin A

immunology

Immunoglobulin G

blood

Immunoglobulin M

blood

Intestines

immunology

Mice

Mice

Inbred BALB C

Mice

Inbred C57BL

Phenol

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)