Construction and expression of immunogenic hybrid enterotoxigenic Escherichia coli CFA/I and CS2 colonization fimbriae for use in vaccines.
Enterotoxigenic Escherichia coli (ETEC) are an important cause of diarrheal morbidity in developing countries, especially in children and also of traveler's diarrhea. Colonization factors (CFs) of ETEC, like CFA/I and CS2 which are genetically and structurally related, play a substantial role in pathogenicity, and since intestinal-mucosal immune responses against CFs appear to be protective, much effort has focused on the development of a CF-based ETEC vaccine. We have constructed hybrid operons in which the major CS2 subunit-encoding cotA gene was inserted into the CFA/I operon, either replacing (hybrid I) or being added to the major CFA/I subunit-encoding cfaB gene (hybrid II). Using specific monoclonal antibodies against the major subunits of CFA/I and CS2, high levels of surface expression of both fimbrial subunits were shown in E. coli carrying the hybrid II operon. Oral immunization of mice with formalin-killed bacteria expressing hybrid II fimbriae induced strong CFA/I- and CS2-specific serum IgG + IgM and fecal IgA antibody responses, which were higher than those achieved by similar immunization with the reference strains. Bacteria expressing hybrid fimbriae are potential candidate strains in an oral-killed CF-ETEC vaccine, and the approach represents an attractive and novel means of producing a broad-spectrum ETEC vaccine.
Tobias
Joshua
J
University of Gothenburg Vaccine Research Institute (GUVAX), 40530 Gothenburg, Sweden., Joshua.Tobias@microbio.gu.se
Svennerholm
Ann-Mari
AM
Holmgren
Jan
J
Lebens
Michael
M
D000595:Amino Acid Sequence; D000818:Animals; D054307:Enterotoxigenic Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D022361:Escherichia coli Vaccines / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D005260:Female; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D016415:Sequence Alignment
D029968:Escherichia coli Proteins; D022361:Escherichia coli Vaccines; D011993:Recombinant Fusion Proteins; C022924:colonization factor antigens; D036781:Fimbriae Proteins