The Uninfected Ixodes Scapularis Human Tick Challenge Model - Acquired Tick Resistance in Naturally Exposed Participants
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 24
- 试验地点
- 1
- 主要终点
- Tick feeding: tick weight
研究概览
简要总结
Tick-borne diseases are increasing worldwide, and there are currently few effective ways to prevent them. One promising new strategy is to develop a vaccine that targets the tick itself ("anti-tick vaccine") to block the transmission of multiple pathogens. Some animals naturally develop resistance to ticks after repeated tick bites. There are indications that a similar form of acquired tick resistance (ATR) may also occur in humans who have been heavily exposed to ticks. This study investigates whether humans can naturally develop tick resistance and how this affects tick feeding. The investigators will compare people with a long history of tick bites and self-reported signs of tick resistance to people who are tick-naïve. The investigators will also include a small group of volunteers who previously participated in an experimental human tick challenge to evaluate what their reaction on tickbites is 1-2 years after their initial exposures.
详细描述
Study Objectives Primary Objective To determine whether humans develop naturally acquired tick resistance by measuring tick feeding success, specifically the weight of ticks after feeding.
Secondary Objectives To measure additional tick feeding parameters (tick mortality, attachment rate, duration of feeding, and molting).
To assess clinical skin reactions such as itch and redness. To study immune responses (antibodies and immune cells) against tick saliva proteins in all groups.
To identify tick salivary antigens that may be useful for future anti-tick vaccine development.
Study Design Single-center, open-label human experimental tick challenge study.
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 70 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Naturally acquired self-reported tick resistant individuals:
- •Age: 18 - 70 years;
- •History of repeated tick bites
- •Local reaction (like redness or itch) at place of previous tick bites and/or signs of impaired tick feeding after bite (anamnestic)
- •Age: 18 years - 70 years;
- •Experimentally acquired tick resistant individuals:
- •Previous participant in the TICK ME study that has completed all 4 challenges
- •Age: 18 years - 70 years;
排除标准
- •Current suspicion of any tick-borne disease
- •Diagnosed with tick-borne disease within the last year
- •Chronic skin condition affecting the skin of the arm;
- •Inability to maintain the dressing for any reason;
- •Known immunodeficiency or autoimmune disease;
- •Use of systemic immunomodulating drugs or chemotherapy, current or in the past;
- •Chronic use of antibiotics;
- •Unable to give informed consent or do not have a thorough command of the Dutch language;
- •Refusal to participate in specimen collection and storage for future study related use;
- •Pregnant or breastfeeding women;
- •Not willing to use adequate contraception during the study period;
- •Red meat allergy (both medically confirmed and self-reported);
- •Use of investigational therapy and devices during the time of the study;
- •Any other condition that, in the opinion of the investigator, would make the patient unsuitable for enrolment or could interfere with the patient participating in and completing the study.
- •Additional exclusion criteria for controls:
- •Known history of tick bites;
- •Positive Borrelia serology (VlsE1/PepC10 ELISA);
- •Known history or current suspicion on any tick-borne disease
- •Additional exclusion criteria for experimentally acquired tick resistant individuals:
- •History of tick bites acquired outside of TICK ME study;
- •Positive Borrelia serology (VlsE1/PepC10 ELISA);
- •Known history or current suspicion on any tick-borne disease
研究组 & 干预措施
Tick naive individuals
Individuals who have never been bitten by ticks before (as far as known)
干预措施: Tick challenge (Other)
Supposed tick immune individuals
Individuals who have been bitten by a lot of ticks before and experience a local reaction after each tickbite.
干预措施: Tick challenge (Other)
Previous TICK ME participants
Individuals who have participated in the TICK ME study
干预措施: Tick challenge (Other)
结局指标
主要结局
Tick feeding: tick weight
时间窗: From the start of the tick challenge until feeding to repletion of the ticks (max 10 days)
Tick weight measured in mg after complete feeding of the tick
次要结局
- Tick feeding: tick mortality(From the start of the tick challenge until feeding to repletion of the ticks (max 10 days))
- Host reaction: redness(Redness will be monitored at day 2 and the last day of the tick challenge)
- Host reaction: itch(Itch is measures daily during the tick challenge (From the start of the tick challenge until feeding to repletion of the ticks (max 10 days))
- Host immune response: humoral(From the start of the challenge, day 2, day 5, final day of challenge (day 5-10) depending upon tick feeding, 3-5 weeks after the challenge and 10-12 weeks after the challenge)
- Host immune response: cellular(From the start of the challenge, day 2, day 5, final day of challenge (day 5-10) depending upon tick feeding, 3-5 weeks after the challenge and 10-12 weeks after the challenge)
研究者
prof. J.W.R. Hovius, MD, PhD
prof. dr.
Amsterdam UMC, location AMC