Expression and Immunogenicity of Enterotoxigenic Escherichia coli Heat-Labile Toxin B Subunit in Transgenic Rice Callus

ABSTRACT Enterotoxigenic Escherichia coli (ETEC) is one of the leading causes of diarrhea among Israeli soldiers serving in field units. Two double-blind placebo-controlled, randomized trials were performed among 155 healthy volunteers to evaluate the safety and immunogenicity of different lots of the oral, killed ETEC vaccine consisting of two doses of whole cells plus recombinantly produced cholera toxin B subunit (rCTB). The two doses of vaccine lot E005 and the first dose of vaccine lot E003 were well tolerated by the volunteers. However, 5 (17%) vaccinees reported an episode of vomiting a few hours after the second dose of lot E003; none of the placebo recipients reported similar symptoms. Both lots of vaccine stimulated a rate of significant antibody-secreting cell (ASC) response to CTB and to colonization factor antigen I (CFA/I) after one or two doses, ranging from 85 to 100% and from 81 to 100%, respectively. The rate of ASC response to CS2, CS4, and CS5 was slightly lower than the rate of ASC response induced to CTB, CFA/I, and CS1. The second vaccine dose enhanced the response to CTB but did not increase the frequencies or magnitude of ASC responses to the other antigens. The two lots of the ETEC vaccine induced similar rates of serum antibody responses to CTB and CFA/I which were less frequent than the ASC responses to the same antigens. Based on these safety and immunogenicity data, an efficacy study of the ETEC vaccine is under way in the Israel Defense Force.

Download Full-text

Reduced doses of oral killed enterotoxigenic Escherichia coli plus cholera toxin B subunit vaccine is safe and immunogenic in Bangladeshi infants 6–17 months of age: Dosing studies in different age groups

Vaccine ◽

10.1016/j.vaccine.2005.08.110 ◽

2006 ◽

Vol 24 (10) ◽

pp. 1726-1733 ◽

Cited By ~ 41

Author(s):

F QADRI ◽

T AHMED ◽

F AHMED ◽

Y BEGUM ◽

D SACK ◽

...

Keyword(s):

Escherichia Coli ◽

Cholera Toxin ◽

Subunit Vaccine ◽

Age Groups ◽

Enterotoxigenic Escherichia Coli ◽

Cholera Toxin B Subunit ◽

Toxin B ◽

Cholera Toxin B ◽

B Subunit

Download Full-text

Expression of Chlamydophila psittaci MOMP heat-labile toxin B subunit fusion gene in transgenic rice

Biologicals ◽

10.1016/j.biologicals.2008.04.002 ◽

2008 ◽

Vol 36 (5) ◽

pp. 296-302 ◽

Cited By ~ 12

Author(s):

Xiuxiang Zhang ◽

Ziguo Yuan ◽

Xuejun Guo ◽

Jingwen Li ◽

Zhaonan Li ◽

...

Keyword(s):

Transgenic Rice ◽

Fusion Gene ◽

Toxin B ◽

B Subunit ◽

Heat Labile ◽

Chlamydophila Psittaci

Download Full-text

Binding specificities of heat-labile enterotoxins isolated from porcine and human enterotoxigenic Escherichia coli for different gangliosides

Canadian Journal of Microbiology ◽

10.1139/m89-109 ◽

1989 ◽

Vol 35 (6) ◽

pp. 670-673 ◽

Cited By ~ 12

Author(s):

Shunji Sugii ◽

Takao Tsuji

Keyword(s):

Escherichia Coli ◽

Competitive Binding ◽

Enterotoxigenic Escherichia Coli ◽

Type B ◽

Binding Assays ◽

B Subunit ◽

Human Type ◽

Heat Labile ◽

Sepharose 4B ◽

Competitive Binding Assays

The binding specificities of heat-labile enterotoxins (LTp and LTh) isolated from porcine and human enterotoxigenic Escherichia coli on human erythrocytes were studied by competitive binding assays using different gangliosides as inhibitors. The binding of 125I–labeled LTp to neuraminidase-treated human type A erythrocytes was most effectively inhibited by ganglioside GM1 Ganglioside GM1 was 11 and 105 times more potent than gangliosides GD1b and GM2, respectively. Gangliosides GD1a, GT1b, and GM3 were much less potent. Similar results were also obtained in competitive binding assays with the 125I-labeled B subunit of LTh and neuraminidase-treated human type B erythrocytes, and in those with 3H-labeled ganglioside GM1 and LTp-coupled Sepharose 4B. The binding of 3H-labeled ganglioside GM1 to LTp was not effectively inhibited by galactose-β(1 → 3)N-acetyl-D-galactosamine at the highest concentration used. These findings suggest that the combining sites of LTp and LTh may be specific for at least the galactose-N-acetyl-D-galactosamine-galactose (N-acetyl-neuraminic acid) portion of ganglioside GM1.Key words: binding specificity, heat-labile enterotoxin, enterotoxigenic Escherichia coli, ganglioside.

Download Full-text

Protective efficacy of a Mycoplasma pneumoniae P1C DNA vaccine fused with the B subunit of Escherichia coli heat-labile enterotoxin

Canadian Journal of Microbiology ◽

10.1139/w2012-051 ◽

2012 ◽

Vol 58 (6) ◽

pp. 802-810 ◽

Cited By ~ 4

Author(s):

Cuiming Zhu ◽

Shiping Wang ◽

Shihai Hu ◽

Minjun Yu ◽

Yanhua Zeng ◽

...

Keyword(s):

Escherichia Coli ◽

Mycoplasma Pneumoniae ◽

Dna Vaccine ◽

Protective Efficacy ◽

Interferon Γ ◽

Toxin B ◽

B Subunit ◽

Heat Labile ◽

Carboxy Terminal Region ◽

Carboxy Terminal

In the present study, we investigated the immunomodulatory responses of a DNA vaccine constructed by fusing Mycoplasma pneumoniae P1 protein carboxy terminal region (P1C) with the Escherichia coli heat-labile toxin B subunit (LTB). BALB/c mice were immunized by intranasal inoculation with control DNAs, the P1C DNA vaccine or the LTB–P1C fusion DNA vaccine. Levels of the anti-M. pneumoniae antibodies and levels of interferon-γ and IL-4 in mice were increased significantly upon inoculation of the LTB–P1C fusion DNA vaccine when compared with the inoculation with P1C DNA vaccine. The LTB–P1C fusion DNA vaccine efficiently enhanced the M. pneumoniae-specific IgA and IgG levels. The IgG2a/IgG1 ratio was significantly higher in bronchoalveolar lavages fluid and sera from mice fusion with LTB and P1C than mice receiving P1C alone. When the mice were challenged intranasally with 107 CFU M. pneumoniae strain (M129), the LTB–P1C fusion DNA vaccine conferred significantly better protection than P1C DNA vaccine (P < 0.05), as suggested by the results, such as less inflammation, lower histopathological score values, lower detectable number of M. pneumoniae strain, and lower mortality of challenging from 5 × 108 CFU M. pneumoniae. These results indicated that the LTB–P1C fusion DNA vaccine efficiently improved protective efficacy against M. pneumoniae infection and effectively attenuated development of M. pneumoniae in mice.

Download Full-text