Baseline Assessment of Skin Resident Memory T Cells in Healthy Unvaccinated Participants
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-50
SponsorInstitute of Tropical Medicine, Belgium
About this trial
In The main GeKoSkimm trial (= A randomized controlled trial to compare the immunogenicity and skin imprinting of intradermal, subcutaneous and intramuscular yellow fever vaccination) the investigators try to understand whether the route of injection (in the muscle, under the skin, or in the skin) when giving the yellow fever vaccine affects the strength of the body's immune response to yellow fever. More in particular the investigators want to know how well the immune responses are retained in the skin, as this is the place where the virus enters the body after a mosquito bite. This will be important for vaccines against infections transmitted via bites of mosquitoes and ticks, such as yellow fever virus. Because this is the first attempt on human samples and only skin samples after vaccination with yellow fever vaccine are available, the investigators want to assess the baseline or background immune response in 'unvaccinated' skin. Therefore, 40 volunteers will be recruited that have not been previously vaccinated against yellow fever and will not receive a yellow fever vaccine during this study. The participant will be requested to provide two skin samples from the upper arm and a blood sample to confirm their vaccination status regarded to yellow fever.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
BMI >/=18,5 kg/m2 and ≤35 kg/m2
Agreement to share and discuss participant's medical history and medical records when relevant with the study team
Able and willing to provide written informed consent
Agreement to refrain from blood donation and other vaccinations during the study
Disqualifiers
Participants with a confirmed flavivirus infection in the past
Participants who received a flavivirus vaccination prior to enrolment (e.g. YFV, Japanese encephalitis virus, tick-borne encephalitis virus, Dengue)
Receipt of any vaccine (licensed or experimental) within 30 days prior to enrolment or during the study
Active participation in another interventional clinical study with active substance intake or large medical procedures affecting the study procedures during or 1 month prior to enrolment
Trial design
Design model
Single group
Treatments tested in this trial
Skin punch biopsy
Procedure/Surgery2 x 4mm skin punch biopsies in the upper arm will be taken from each participant at visit 2 with additional microsampling (microbiopsy and wound blood sampling)
Blood samples
Procedure/SurgeryBlood sampling of 15 mL (10mL Lithium-Heparine + 5 mL SST) is performed on Visit 1 to confirm their vaccination status regarded to yellow fever
Treatment groups
40 Participants
are divided into 1 treatment groupGroup A: Healthy unvaccinated participants against yellow fever virusOther 2 interventions
Trial outcomes
Primary outcomes
1
Estimate the baseline number and proportion of skin-resident memory T cells against YFV (YFV-TRM) in the skin of unvaccinated and healthy volunteers against YFV
The number and proportion of YFV-specific T cells within the skin-resident lymphocyte parent population at visit 2, measured by flow cytometry.
Time frame
Day 14 (Visit 2)Secondary outcomes
1
Estimate the baseline number and proportion of circulating effector- (YFV-TEM) and central-memory T cells against YFV (YFV-TCM) in the blood of unvaccinated and healthy volunteers against YFV
The number and proportion of circulating YFV-specific TCM and TEM cells within the CD3+ lymphocyte parent population at visit 1
Time frame
Day 0 (Visit 1)Other outcomes
1
Estimate the baseline cytokine and chemokine concentrations in capillary blood, and microbiopsies of unvaccinated and healthy volunteers against YFV
The number of cytokine and chemokine concentrations (ng/ul) in capillary blood, and microbiopsies at visit 2
Time frame
Day 14 (Visit 2)2
Estimate the baseline YFV-specific IgG/IgM levels in capillary blood of unvaccinated and healthy volunteers
IgG/IgM levels (mean fluorescence intensity) in capillary blood at visit 2
Time frame
Day 14 (Visit 2)3
Describe the spatially-resolved position of TRM cells in the skin of unvaccinated and healthy volunteers against YFV
Spatially-resolved YFV-specific TCR clonotypes in the skin at visit 2
Time frame
D14 (Visit 2)4
Determine the baseline TCR diversity index in the skin of unvaccinated healthy volunteers against YFV
TCR diversity index in the skin at visit 2
Time frame
Day 14 (Visit 2)Sponsors and contacts
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Source ClinicalTrials.gov