The purpose of the study is to determine if immunization with a chimeric E. coli protein, dsc14CfaE-sCT2/LTB5, is safe and immunogenic when administered by vaccination under the skin.
The purpose of the study is to evaluate the safety and immunogenicity of dsc14cfaEsCTA2/LTB5 (Chimera) and dscCfaE administered with and without LTR192G by intradermal (ID) immunization and to gather additional data on the administration of dsCfaE and LTR192G via transcutaneous immunization (TCI) route. If vaccines are found to be safe and adequately immunogenic in humans, a down-selection would occur and a phase 2b vaccination/challenge study would be undertaken to further evaluate vaccine safety and allow a preliminary assessment of efficacy of one of these candidates by the ID or TCI route. With favorable evidence for safety, immunogenicity, efficacy, complemented by advances in standard methodology to combine multiple adhesins with an appropriate LT enterotoxoid form, a multivalent vaccine would be constructed and evaluated for further clinical development.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
57
Walter Reed Army Institute of Research Clinical trial Center
Silver Spring, Maryland, United States
Safety - Occurrence of Adverse Events
Occurrence of related and unrelated to vaccine AE's
Time frame: 1 year
Number of Participants With Immune Responses to Vaccine Antigens
Number of participants with immune responses to vaccine antigens from baseline. Peripheral blood mononuclear cells (PBMCs) were collected to determine IgA antibody secreting cells (ASC) responses to dscCfaE and LTB. For each antigen, pre-and post-dosing samples were tested for total and vaccine-specific numbers of IgA-ASCs using the ELISPOT assay. A positive IgA-ASC response was defined as a \> 2-fold increase over the baseline value of the ASC per 10\^6 PBMC, when the number of ASC was \>0.5 per 10\^6 in the baseline sample. When the number of baseline ASCs was less than 0.5 per 10 PBMC, a subject was considered a responder if the post-vaccination value was greater than 1.0 per 10\^6 PBMC.
Time frame: baseline and post dose
Antigen-Specific IgA Geometric Mean Titers
Antigen-Specific IgA Geometric Mean Titers as defined by Fecal IgA. Final Clinical Study Report (FCSR) highlighted titer numbers only; no numbers for measure of dispersion/precision were given; no explanation as to why standard deviation information is not present in the FCSR.
Time frame: Day 0, 21,42, 56, 70
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