Immune Responses After Human Subject Challenge With Sand Fly Bites

This study is ongoing, but not recruiting participants.
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Uniformed Services University of the Health Sciences
ClinicalTrials.gov Identifier:
NCT01289977
First received: February 3, 2011
Last updated: May 29, 2015
Last verified: May 2015
  Purpose

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
Healthy

Study Type: Observational
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

Resource links provided by NLM:


Further study details as provided by Uniformed Services University of the Health Sciences:

Primary Outcome Measures:
  • 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.


Enrollment: 68
Study Start Date: October 2010
Estimated Study Completion Date: April 2016
Primary Completion Date: July 2014 (Final data collection date for primary outcome measure)
Groups/Cohorts
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.

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.

  Eligibility

Ages Eligible for Study:   18 Years to 50 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

Male and female military health care beneficiaries in good health, age 18-50

Criteria

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
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01289977

Locations
United States, Maryland
Walter Reed National Military Medical Center
Bethesda, Maryland, United States, 20814
Sponsors and Collaborators
Uniformed Services University of the Health Sciences
Investigators
Principal Investigator: Naomi E Aronson, MD Uniformed Services University of the Health Sciences
  More Information

No publications provided

Responsible Party: Uniformed Services University of the Health Sciences
ClinicalTrials.gov Identifier: NCT01289977     History of Changes
Other Study ID Numbers: G183ZU, Y1-AI-0744-01
Study First Received: February 3, 2011
Last Updated: May 29, 2015
Health Authority: United States: Federal Government

Keywords provided by Uniformed Services University of the Health Sciences:
Sandfly
leishmaniasis
immune response
individuals age 18-50

ClinicalTrials.gov processed this record on July 30, 2015