Investigating the Human Immune Response to Ixodes Scapularis Tick Bites
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.
‣ 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