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Immune Responses After Human Subject Challenge With Sand Fly Bites

Sponsor
Uniformed Services University of the Health Sciences (U.S. Fed)
Overall Status
Completed
CT.gov ID
NCT01289977
Collaborator
National Institute of Allergy and Infectious Diseases (NIAID) (NIH)
68
Enrollment
1
Location
66.5
Duration (Months)
1
Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease Intervention/Treatment Phase

    Detailed Description

    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.

    Study Design

    Study Type:
    Observational
    Actual Enrollment :
    68 participants
    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
    Study Start Date :
    Oct 1, 2010
    Actual Primary Completion Date :
    Apr 1, 2016
    Actual Study Completion Date :
    Apr 15, 2016

    Arms and Interventions

    Arm Intervention/Treatment
    Phlebotomus group

    Those in the Phlebotomus group will have exposure to P. duboscqui sand fly
    Lutzomyia group

    Those placed in this group will receive exposure to L. longipalpis sand fly bites.

    Outcome Measures

    Primary Outcome Measures

    1. Human Th1 immune response to specific sand fly salivary proteins [6-18 months]

      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.

    Eligibility Criteria

    Criteria

    Ages Eligible for Study:
    18 Years to 50 Years
    Sexes Eligible for Study:
    All
    Accepts Healthy Volunteers:
    Yes
    Inclusion Criteria:

    • Age 18-50

    • Plans to remain in DC area for at least one year

    • willingness to participate in all study procedures

    • general good health

    • military health care beneficiary

    • able to provide informed consent

    Exclusion Criteria:

    • Prior travel to geographic areas where leishmania transmitting sand flies are common

    • positive antibody to sand fly saliva on screening blood test

    • pregnancy

    • elevated serum IgE

    • history of chronic medical illness

    • adult history of treatment requiring anemia

    • large reactions to insect bites

    • history of multiple vasovagal reactions to phlebotomy

    • difficult venous access for phlebotomy

    • Taking medications that could interfere with immune responses

    Contacts and Locations

    Locations

    Site City State Country Postal Code
    1 Walter Reed National Military Medical Center Bethesda Maryland United States 20814

    Sponsors and Collaborators

    • Uniformed Services University of the Health Sciences
    • National Institute of Allergy and Infectious Diseases (NIAID)

    Investigators

    • Principal Investigator: Naomi E Aronson, MD, Uniformed Services University of the Health Sciences

    Study Documents (Full-Text)

    None provided.

    More Information

    Publications

    None provided.
    Responsible Party:
    Uniformed Services University of the Health Sciences
    ClinicalTrials.gov Identifier:
    NCT01289977
    Other Study ID Numbers:
    • G183ZU
    • Y1-AI-0744-01
    First Posted:
    Feb 4, 2011
    Last Update Posted:
    Feb 19, 2018
    Last Verified:
    Feb 1, 2018
    Keywords provided by Uniformed Services University of the Health Sciences
    Sandfly
    leishmaniasis
    immune response
    individuals age 18-50

    Study Results

    No Results Posted as of Feb 19, 2018