Phase 1 N=42 Basic Science

Characterization of Skin Immunity to Aedes Aegypti Saliva in Dengue-endemic Participants in Cambodia

Vector Borne Diseases

Bottom Line

View on ClinicalTrials.gov: NCT04350905 ↗

Enrolled (actual)

Serious AEs

0.0%

Results posted

Apr 2022

Primary outcome: Primary: Measurement of Change in Early and Late Innate Immune Responses Using Gene Expression and Flow Cytometry in Participants' Skin — 50; 5 % of total dendritic cells

Study Design & Population

Study type: Interventional
Phase: Phase 1
Interventions: Mosquito Feeding (Other)
Age: Adult · 18+ yrs
Sex: All
Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)
Primary completion: Apr 2021

Outcome Measures

Outcome	Result	p-value
PRIMARY Measurement of Change in Early and Late Innate Immune Responses Using Gene Expression and Flow Cytometry in Participants' Skin	50; 5	—
PRIMARY Measurement of Changes in the Adaptive Immune Response and Cellular Recruitment in the Skin of Bitten Versus Unbitten Skin After Sixth and Final Feeding in Each Vector Group.	—	—
SECONDARY Flow Cytometry Analysis of PBMCs Collected Day 0 (Baseline) and Days 2 and 14 After Feeding for Saliva-specific T-cells	—	—

Summary

Background: Mosquito-borne viruses like dengue cause major illness and death worldwide, particularly in Southeast Asia. When mosquitoes deliver a virus into the skin of humans, they also leave saliva. Researchers want to learn more about skin immunity to mosquito saliva. They hope this will help with future vaccines and treatments for these diseases. Objective: To compare the early and late innate immune response in the skin of Aedes aegypti bitten versus unbitten skin. Eligibility: Healthy people ages 18-45 who live within about 15 km of the study site in Chbar Mon Design: Participants will have 3 visits. The baseline/screening visit will include: Medical and medication history Questions about participants demographic information, mosquito biting risk factors, and responses to mosquito or other insect bites Physical exam Urine sample for some participants Mosquito feeding. A feeding device will be placed on the participant s arm for up to 20 minutes. The insects will feed through a mesh on the bottom of the feeding device. Participants may be given standard treatments for any skin reactions. Blood tests Four skin biopsies taken from bitten and unbitten skin. Local anesthetic will be administered, and a small tool will be used to remove the participant s skin. Participants will have a second visit the next day. They will have a physical exam and blood tests. They will have 1 skin biopsy. Participants will have a final visit about 2 weeks later. They will have a physical exam and blood tests. During the study, participants will be asked to take measures to prevent more mosquito bites.

Eligibility Criteria

INCLUSION CRITERIA:

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

-Provision of signed and dated informed consent form

Stated willingness to comply with all study procedures and availability for the duration of the study
Male or female, aged 18 - 45 years
Live within approximately 15 km of study site
In good general health as evidenced by medical history
Willing to allow biological samples to be stored for future research.
A female is eligible for this study if she meets 1 of the following:
Of non-childbearing potential (i.e., women who have had a hysterectomy or tubal

ligation or are postmenopausal, as defined by no menses in >=1 year).

--Of childbearing potential but has negative urine pregnancy test on Day 0

Agrees to not use scented lotions, deodorants, or topical creams on each feeding day.
Agrees to not take aspirin or any other NSAID (ex. ibuprofen) within 7 days of a biopsy.
Agrees to not use oral or topical antihistamines or steroid creams or ointments throughout the

study without prior permission of Principal Investigator (PI).

EXCLUSION CRITERIA

-Any underlying or current medical condition that, in the opinion of the investigator, would

interfere with participation in the study.

-History of severe allergic reaction (including to mosquito or other insect bites) with generalized

urticaria, angioedema, anaphylaxis, anaphylactoid reaction or any other reaction described by

the participant and deemed severe by the PI.

Self-reported or known history of alcoholism or drug abuse within 6 months prior to enrollment
Self-reported or known history of psychiatric or psychological issues that require treatment and

are deemed by the PI to be a contraindication to protocol participation.

-Any use of medications that affect blood clotting within 3 months or history of abnormal blood

clotting

-History of significant scarring such as keloids after previous biopsies, lacerations, abrasions,

surgeries, or other skin procedures (e.g., cosmetic piercings) that are deemed by the PI to be a

contraindication to protocol participation.

-Pregnant or breastfeeding.

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT04350905). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.