Over-expression of major colonization factors of enterotoxigenic Escherichia coli, alone or together, on non-toxigenic E. coli bacteria

• Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrheal disease and deaths among children in developing countries and the major cause of traveller's diarrhea. Since surface protein colonization factors (CFs) of ETEC are important for pathogenicity and immune protection is mainly mediated by locally produced IgA antibodies in the gut, much effort has focused on the development of an oral CF-based vaccine. We have recently described the development of recombinant strains over-expressing CFA/I; the most prevalent CF among human clinical ETEC isolates. Here, non-toxigenic recombinant E. coli strains over-expressing Coli surface antigen 2 (CS2), CS4, CS5, and CS6, either alone, or each in combination with CFA/I were constructed by cloning the genes required for expression and assembly of each CF into expression vectors harboring a strong promoter. Immunological assays showed that recombinant strains expressing single CFs produced those in significantly larger amounts than did corresponding naturally high producing reference strains. Recombinant strains co-expressing CFA/I together with another CF also expressed significantly larger amounts of both CFs compared with the corresponding references strains. Further, when tested in mice, oral immunization with formalin-killed recombinant bacteria co-expressing one such double-expression CF pair, CFA/I. +. CS2, induced specific serum IgG. +. IgM and fecal IgA antibody responses against both CFs exceeding the responses induced by immunizations with natural reference strains expressing CFA/I and CS2, respectively. We conclude that the described type of recombinant bacteria over-expressing major CFs of ETEC, alone or in combination, may be useful as candidate strains for use in an oral whole-cell CF-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

Anti-colonization immunity

Co-expression

Colonization factors

ETEC

ETEC vaccine

Over-expression

Escherichia coli vaccine

formaldehyde

immunoglobulin A antibody

immunoglobulin G

immunoglobulin M

membrane antigen

membrane protein

protein colonization factor i

surface antigen 2

surface antigen 4

surface antigen 5

surface antigen 6

unclassified drug

animal experiment

animal model

antibody response

article

bacterial strain

controlled study

enterotoxigenic Escherichia coli

Escherichia coli infection

female

gene overexpression

molecular cloning

mouse

nonhuman

nucleotide sequence

priority journal

Animals

Antibodies

Bacterial

Antigens

Bacterial

Escherichia coli Infections

Escherichia coli Proteins

Escherichia coli Vaccines

Fimbriae Proteins

Mice

Mice

Inbred BALB C

Recombinant Proteins

Recombination

Genetic

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)