Immune Responses After Human Subject Challenge With Sand Fly Bites: Exploratory Study for Selection of Potential Leishmania Vaccine Antigen Candidates
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 68
- 试验地点
- 1
- 主要终点
- Human Th1 immune response to specific sand fly salivary proteins
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 50 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •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
排除标准
- •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
结局指标
主要结局
Human Th1 immune response to specific sand fly salivary proteins
时间窗: 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.
次要结局
未报告次要终点