Evaluation of transcutaneous immunization as a delivery route for an enterotoxigenic E. coli adhesin-based vaccine with CfaE, the colonization factor antigen 1 (CFA/I) tip adhesin

ABSTRACT The assembly of pilus colonization factor antigen III (CFA/III) of enterotoxigenic Escherichia coli (ETEC) requires the processing of CFA/III major pilin (CofA) by a prepilin peptidase (CofP), similar to other type IV pilus formation systems. CofA is produced initially as a 26.5-kDa preform pilin (prepilin) and then processed to a 20.5-kDa mature pilin by CofP which is predicted to be localized in the inner membrane. In the present experiment, we determined the nucleotide sequence of the whole region for CFA/III formation and identified a cluster of 14 genes, includingcofA and cofP. Several proteins encoded bycof genes were similar to previously described proteins, such as the toxin-coregulated pili of Vibrio cholerae and the bundle-forming pili of enteropathogenic E. coli. The G+C content of the cof gene cluster was 37%, which was significantly lower than the average for the E. coli genome (50%). The introduction of a recombinant plasmid containing thecof gene cluster into the E. coli K-12 strain conferred CFA/III biogenesis and the ability of adhesion to the human colon carcinoma cell line Caco-2. This is the first report of a complete nucleotide sequence of the type IV pili found in human ETEC, and our results provide a useful model for studying the molecular mechanism of CFA/III biogenesis and the role of CFA/III in ETEC infection.

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Expression of Recombinant EnterotoxigenicEscherichia coli Colonization Factor Antigen I bySalmonella typhimurium Elicits a Biphasic T Helper Cell Response

Infection and Immunity ◽

10.1128/iai.67.12.6249-6256.1999 ◽

1999 ◽

Vol 67 (12) ◽

pp. 6249-6256 ◽

Cited By ~ 39

Author(s):

David W. Pascual ◽

David M. Hone ◽

Stacy Hall ◽

Frederik W. van Ginkel ◽

Masafumi Yamamoto ◽

...

Keyword(s):

Protective Immunity ◽

Lymphoid Tissues ◽

T Helper ◽

Gi Tract ◽

E Coli ◽

Colonization Factor ◽

Th Cell ◽

Ifn Γ ◽

Colonization Factor Antigen I ◽

Factor Antigen

ABSTRACT Protective immunity to enterotoxigenic Escherichia coli(ETEC) is antibody (Ab) dependent; however, oral immunization with purified ETEC fimbriae fails to elicit protective immunity as a consequence of antigenic alteration by the gastrointestinal (GI) tract. Unless unaltered ETEC fimbriae can reach the inductive lymphoid tissues of the GI tract, immunity to ETEC cannot be induced. To produce immunity, live vectors, such as Salmonella typhimurium, can effectively target passenger antigens to the inductive lymphoid tissues of the GI tract. By convention, oral immunizations withSalmonella vectors induce CD4+ T helper (Th) cell responses by gamma interferon (IFN-γ)-dominated pathways both to the vector and passenger antigen, resulting in serum immunoglobulin G2a (IgG2a) and modest mucosal IgA Ab responses. In the present study, mice orally immunized with a Salmonella vector engineered to stably express ETEC colonization factor antigen I (CFA/I) showed initially elevated serum IgG1 and mucosal IgA anti-CFA/I Ab responses. As expected, mice orally immunized with an E. coli-CFA/I construct elicited poor anti-CFA/I Ab responses. In fact, the addition of cholera toxin during oral E. coli-CFA/I immunization failed to greatly enhance mucosal IgA Ab responses. Seven days after immunization with the Salmonella-CFA/I construct, cytokine-specific ELISPOT showed induction of predominant Th2-type responses in both mucosal and systemic immune compartments supporting the early IgG1 and IgA anti-CFA/I Abs. By 4 weeks, the Th cell response became Th1 cell dominant from the earlier Th2-type responses, as evidenced by increased mucosal and systemic IFN-γ-producing T cells and a concomitant elevation of serum IgG2a Ab responses. This biphasic response offers an alternative strategy for directingSalmonella vector-induced host immunity along a Th2 cell-dependent pathway, allowing for early promotion of mucosal and systemic Abs.

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Escherichia coli O8:H8 Carrying a Novel Variant of the Heat-Labile Enterotoxin LT2 Gene Caused Outbreaks of Diarrhea

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa021 ◽

2020 ◽

Vol 7 (1) ◽

Cited By ~ 2

Author(s):

Kai Ishimaru ◽

Mari Sasaki ◽

Hiroshi Narimatsu ◽

Yoko Arimizu ◽

Yasuhiro Gotoh ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Determinants ◽

Human Pathogen ◽

E Coli ◽

Colonization Factor ◽

Heat Labile ◽

Novel Variant ◽

Factor Antigen

Abstract No outbreaks caused by Escherichia coli–producing heat-labile enterotoxin LT2 have been reported to date. Here, we revealed that the E. coli O8:H8 strains isolated from patients in 2 independent diarrhea outbreaks were negative for any known virulence determinants in routine microbiological tests, were very closely related, and carried a prophage-encoded gene for a novel LT2 variant (LT2d) and the genes for colonization factor antigen III. We also showed that LT2d has a cytotonic activity similar to LT1. These data indicate the importance of E. coli strains producing LT2d as a human pathogen.

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Immunization of rabbits with enterotoxigenic E. coli colonization factor antigen (CFA/I) encapsulated in biodegradable microspheres of poly (lactide-co-glycolide)

Vaccine ◽

10.1016/0264-410x(93)90012-m ◽

1993 ◽

Vol 11 (2) ◽

pp. 155-158 ◽

Cited By ~ 51

Author(s):

Robert Edelman ◽

Robert G. Russell ◽

Genevieve Losonsky ◽

Ben D. Tall ◽

Carol O. Tacket ◽

...

Keyword(s):

Biodegradable Microspheres ◽

E Coli ◽

Colonization Factor ◽

Factor Antigen

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Multiepitope Fusion Antigen Induces Broadly Protective Antibodies That Prevent Adherence of Escherichia coli Strains Expressing Colonization Factor Antigen I (CFA/I), CFA/II, and CFA/IV

Clinical and Vaccine Immunology ◽

10.1128/cvi.00652-13 ◽

2013 ◽

Vol 21 (2) ◽

pp. 243-249 ◽

Cited By ~ 18

Author(s):

Xiaosai Ruan ◽

David E. Knudsen ◽

Katie M. Wollenberg ◽

David A. Sack ◽

Weiping Zhang

Keyword(s):

Escherichia Coli ◽

Diarrheal Disease ◽

Vaccine Development ◽

Bacterial Colonization ◽

Content Type ◽

E Coli ◽

Colonization Factor ◽

Protective Antibodies ◽

Factor Antigen ◽

Fusion Antigen

ABSTRACTDiarrhea is the second leading cause of death in children younger than 5 years and continues to be a major threat to global health. EnterotoxigenicEscherichia coli(ETEC) strains are the most common bacteria causing diarrhea in developing countries. ETEC strains are able to attach to host small intestinal epithelial cells by using bacterial colonization factor antigen (CFA) adhesins. This attachment helps to initiate the diarrheal disease. Vaccines that induce antiadhesin immunity to block adherence of ETEC strains that express immunologically heterogeneous CFA adhesins are expected to protect against ETEC diarrhea. In this study, we created a CFA multiepitope fusion antigen (MEFA) carrying representative epitopes of CFA/I, CFA/II (CS1, CS2, and CS3), and CFA/IV (CS4, CS5, and CS6), examined its immunogenicity in mice, and assessed the potential of this MEFA as an antiadhesin vaccine against ETEC. Mice intraperitoneally immunized with this CFA MEFA exhibited no adverse effects and developed immune responses to CFA/I, CFA/II, and CFA/IV adhesins. Moreover, after incubation with serum of the immunized mice, ETEC orE. colistrains expressing CFA/I, CFA/II, or CFA/IV adhesins were significantly inhibited in adherence to Caco-2 cells. Our results indicated this CFA MEFA elicited antibodies that not only cross-reacted to CFA/I, CFA/II and CFA/IV adhesins but also broadly inhibited adherence ofE. colistrains expressing these seven adhesins and suggested that this CFA MEFA could be a candidate to induce broad-spectrum antiadhesin protection against ETEC diarrhea. Additionally, this antigen construction approach (creating an MEFA) may be generally used in vaccine development against heterogenic pathogens.

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