Characterization of Human Immune Signatures to Zoonotic Virus Exposure in Cambodia

Recruiting

Brief Summary: This is a biospecimen procurement protocol to characterize the immune response to zoonotic virus exposure in healthy adult humans aged 18 to 65 years with high-risk exposure to animals or their excreta (e.g., guano farming and wet markets), or living within 5 km of animal habitats (e.g., bat caves and bat roosts) in Cambodia.

Detailed Description: This is a biospecimen procurement protocol to characterize immune signatures to zoonotic virus exposure in healthy adult humans aged 18 to 65 years who handle suspected infected animals or their excreta, or living within 5 km of animal reservoirs, in Cambodia.

The primary study objective is to characterize immunity to zoonotic viruses, specifically H5N1. To meet this objective, when possible, individuals with the highest likelihood of prior exposure to the viruses of interest (Nipahvirus, bCoVs, H5N1) will be screened for study inclusion. These high-exposure risk behaviors include direct handling of known or suspected infected animals or their excreta. If insufficient individuals meeting these criteria are found, then sampling will include individuals with lower risk exposures, including living or working in areas proximal to (within 5 km of) animal habitats.

All human subjects research activities will be conducted by study personnel within the International Center of Excellence in Research Cambodia, Cambodian CCDC, and the Forestry Administration of the Royal Government of Cambodia. NIH investigators are involved in study design, implementation, analysis of coded samples and data, and writing and dissemination of reports of study results. Although they may support Cambodian investigators in monitoring/oversight capacities, NIH investigators will not be engaged in human subjects research.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Pregnancy (based on self-reporting).
Any underlying, chronic, or current medical condition that, in the opinion of the investigator, would interfere with participation in the study (e.g., inability or great difficulty in drawing blood, known anemia).
Self-reported symptoms suggestive of acute infection (acute myalgias, arthralgias, headache, retro-orbital pain, dyspnea, rash) within 7 days prior to enrollment.
Signs suggestive of acute infection (fever, defined as internal temperature >38°C; hypoxemia, defined as peripheral oxygen saturation of <90%; hypotension, defined as systolic blood pressure <90 mm Hg or diastolic blood pressure <50 mm Hg) present at screening.
Self-reported diagnosis of immune deficiency, including HIV infection, chronic corticosteroid use (≥10 mg prednisone dose or its equivalent for a continuous period of ≥30 days within the last 1 year), ongoing or prior (within the last 10 years) receipt of chemotherapy or immunotherapy, or current hematological malignancy.
Receipt of blood products, including immunoglobulin products, within 120 days of study enrollment.

Primary Outcome Measures

Name	Time	Method
Antibody binding activity in plasma samples against known immunodominant zoonotic viral proteins	Day 0 and 2 optional visits at least 30 days apart between Day 180-720	Measured by binding antibody titer greater than cutoffs established from healthy U.S. donors (3 standard deviations above mean signal intensity) to a panel of either henipaviruses, influenza viruses, or sarbecoviruses
Neutralizing activity of plasma samples against known immunodominant zoonotic viral proteins	Day 0 and 2 optional visits at least 30 days apart between Day 180-720	Measured by circulating antigen-specific B cells constituting approximately 0.001%-0.005% total PBMCs
Isolate viral antigen-specific B cells for phenotyping and immunoglobulin sequencing	Day 0 and 2 optional visits at least 30 days apart between Day 180-720	Measured by isolation of an expected 20 million PBMCs from whole blood samples, yielding approximately 100-500 antigen-specific B cells for single-cell B-cell sequencing (anticipated cell death up to 50% during the isolation and sorting process)

Secondary Outcome Measures

Name	Time	Method