Human Immune Response to Ixodes Scapularis Tick Bites

Recruiting now · Phase 1/Phase 2

Conditions studied: Tick-borne Diseases, Tick Resistance, Lyme Disease

In brief

Background: Each year, the number of cases of tick-borne diseases increases. The deer tick (Ixodes scapularis) is the vector of at least 7 pathogens that cause human diseases, including Lyme disease. Researchers want to learn more to help them develop vaccines against ticks in the future. Objective: To learn how people s bodies, particularly the skin, respond to tick bites. Eligibility: Healthy adults aged 18 years and older who have no known history of a tick-borne disease or tick bite exposure. Design: Participants will be screened with a medical history, physical exam, and blood tests. Participants will have 2 skin punch biopsies of healthy skin. For this, a sharp instrument will be used to remove a round plug of skin about the size of a pencil eraser. Participants will then have 10 clean laboratory-bred ticks placed at 2 different sites on their skin (20 ticks total). The ticks will be removed from the first site 1 day after placement and from the second site 2-4 days after placement. Participants will complete symptom diary cards. They will answer questions about itching at the tick feeding sites. They will give blood samples. Photos will be taken of the tick feeding sites. Skin punch biopsies will be collected at the sites of the tick bites. Participants will repeat the tick feeding procedures 2 times, each 2-8 weeks apart. For the 2nd and 3rd procedures, 10 clean laboratory-bred ticks will be placed at 1 site. The ticks will be removed 2-3 days after tick placement. They will have telephone follow-up visits after each procedure. After the final tick removal, participants will have follow-up visits in 4-6 weeks and again in 3 months. They will give blood samples and discuss how they are feeling. Participation will last about 5-7 months.

Key facts

Study ID

NCT05036707

Run by

National Institute of Allergy and Infectious Diseases (NIAID)

People needed

60

Starts

2022-02-28

Expected to finish

2028-06-30

Last updated by the study team

2026-05-06

Who can join

Age: 18 and older, up to 99. Sex: any. Healthy volunteers: accepted.

You may not qualify if…

• An individual who meets any of the following criteria will be excluded from participation in this study:
• History of forming large thick scars (keloids) after skin injuries.
• History of excessive bleeding after cuts or procedures.
• History of taking anticoagulants in the past 28 days.
• History of allergic reaction to lidocaine.
• History of allergic reaction to tape, adhesive bandages, or dressings.
• Inability to maintain the dressing for any reason.
• Pregnancy or lactation.
• Treatment with another investigational drug or other intervention within the past 30 days.
• Oral or intravenous (IV) steroids in the 2 weeks prior to each tick placement procedure (topical, nasal, inhaled, intra-articular, and replacement doses of steroids are not exclusions).
• History of reactions to mammalian meat, IgE- mediated food allergies, urticaria or anaphylaxis. Mild pollen-food allergy syndrome is not an exclusion.
• History of systemic allergic reaction to venom (bee, wasps and other Hymenoptera stings).
• History of clinically significant drug allergies.
• History of moderate to severe atopy asthma, atopic dermatitis, allergic rhinitis.
• Active severe skin disease, uncontrolled diabetes, cancer other than non-melanoma skin cancers, autoimmune disease requiring immunosuppressive therapy, or history of human immunodeficiency virus (HIV), chronic viral hepatitis, or syphilis.
• Refusal to allow storage of samples and data for future usage..
• Any other condition that, in the opinion of the investigator, would make the patient unsuitable for enrollment or could interfere with the patient participating in and completing the study.
• Exclusion of Select Populations:
• Children:
• Children are excluded from this protocol as there is no direct benefit to the participants, the risk from the skin biopsies is small but above minimal, the procedure is invasive and can be stressful for children, and there is concern over their ability to maintain the LeFlap dressing.
• Pregnant and breastfeeding women:
• Pregnant and breastfeeding women are excluded from trial participation as there is no direct benefit to the participants.
• Adults who lack capacity to consent:
• Adults lacking decision-making capacity to provide informed consent are excluded at screening as there is no direct benefit to the participants.
• Enrolled participants who permanently lose the ability to consent during participation will be monitored for safety but will have no additional research procedures performed.

Where it is running

• National Institutes of Health Clinical Center — Bethesda, Maryland, United States (enrolling)

Full record on ClinicalTrials.gov

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