NCT05036707 · National Institute of Allergy and Infectious Diseases (NIAID)
Human Immune Response to Ixodes Scapularis Tick Bites
What this study is about
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.
View original scientific description
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.
Interventions
DEVICE
Xenodiagnosis Ticks
Larval ticks will be obtained from Dr. Sam Telford from a laboratory maintained tick colony at Tufts Veterinary School. These ticks are hatched from eggs laid by ticks that have fed only on specific pathogen free laboratory animals that were purchased from established vendors.
PROCEDURE
skin biopsy
2-3 mm skin punch biopsies will be performed.
PROCEDURE
blood draw
Peripheral blood draws will be performed.
Primary outcome measures
Assessment of Safety of the device. Use toxicity tables and safety monitoring as specified in the protocol.
Time frame: continuous
Ongoing assessment of safety.
Develop a model of acquired tick resistance in humans. Use validated pruritus scales, numerical rating system, verbal rating system, and visual analogue system.
Time frame: end of study
Clinical measures of tick immunity.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- In order to be eligible to participate in this study, an individual must meet all of the following criteria:
- Stated willingness to comply with all study procedures and availability for the duration of the study.
- Age 18 years or older.
- In good general health as evidenced by medical history.
- No history of TBD.
- No known tick bite.
- Serum IgE level within Clinical Center Department of Laboratory Medicine normal range. https://ccinternal2.cc.nih.gov/LTGRA/UL/public\_labtest\_detail.aspx?next\_flg=Y\&test\_id=4731\&id\_order=53
- Serum tryptase level within Clinical Center Department of Laboratory Medicine normal range. https://ccinternal2.cc.nih.gov/LTGRA/UL/public\_labtest\_detail.aspx?next\_flg=Y\&test\_id=1157\&id\_order=1
- For participants of child-bearing potential: use of effective contraception for at least 1 month prior to tick placement, and agreement to use such a method during study participation and for an additional 3 months after the removal of the last ticks. Types of contraception include abstinence, surgical methods (sterilization, implants, intrauterine device, partner with vasectomy), hormonal methods (birth control pill, patch, ring, injection), or barrier methods (diaphragm plus spermicide, male condom plus spermicide)
- For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner.
- Agree to not participate in other clinical studies requiring investigational interventions for the duration of the study.
- Minimum hemoglobin of 13.0 g/dL for males and 12 g/dL for females
Exclusion criteria
- 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
- Bethesda, Maryland
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 6, 2026 · Source of record for eligibility and locations