Immune Responses After Human Subject Challenge With Sand Fly Bites
Sand flies can carry the infection leishmaniasis (a parasite). The purpose of this study is to evaluate the human immune response to uninfected laboratory raised sand fly bites and select from the immune response to sand fly saliva, possible substances to use for a future vaccine to protect against the parasite leishmaniasis.
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||Immune Responses After Human Subject Challenge With Sand Fly Bites: Exploratory Study for Selection of Potential Leishmania Vaccine Antigen Candidates|
- Human Th1 immune response to specific sand fly salivary proteins [ Time Frame: 6-18 months ] [ Designated as safety issue: No ]Subject blood will be obtained at set points after repeated controlled sand fly feedings, duration for 20 minutes. Sand fly salivary molecules that demonstrate a strong Th1 immune response in these human PBMC, and little Th2 cytokine induction will be considered for development as future leishmania vaccine antigen candidates.
Biospecimen Retention: Samples With DNA
Plasma and white blood cells will be retained.
|Study Start Date:||October 2010|
|Estimated Study Completion Date:||April 2016|
|Primary Completion Date:||July 2014 (Final data collection date for primary outcome measure)|
Those in the Phlebotomus group will have exposure to P. duboscqui sand fly
Those placed in this group will receive exposure to L. longipalpis sand fly bites.
Based on travel history and possible exposure, subjects were entered into one of 2 arms, Ph. dubosqui or Lu. lutzomyia controlled sand fly repeated feedings. At baseline a pheresis was done to collect baseline cells. Subjects received sand fly bites on a q2 week schedule for 2 months followed by a q2 months schedule for one year. They had an option to extend for a late recall feeding at 18 months, when a skin biopsy was performed 48 hours after sand fly bites. Currently the study is fully enrolled and all human subject contact is complete. We (laboratory at NIAID) are studying the humoral, cellular immune responses using blood samples, and cytokine expression in the skin biopsy samples.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01289977
|United States, Maryland|
|Walter Reed National Military Medical Center|
|Bethesda, Maryland, United States, 20814|
|Principal Investigator:||Naomi E Aronson, MD||Uniformed Services University of the Health Sciences|