A Prospective, Open Label Study of Human T Cell Responses to Live Attenuated Japanese Encephalitis Vaccine SA14-14-2

Study Overview
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Brief Summary
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Japanese encephalitis (JE) live attenuated vaccine SA14-14-2 has been in use for more more than 20 years in Asia. JE vaccine SA14-14-2 is licensed in India and has been widely used since 2006. JE vaccines give protection by generating a neutralizing antibody response, but both naturally exposed persons and patients with JE also have T cell responses. Whether JE vaccine SA14-14-2 elicits T cell responses is unknown. This study tests the hypothesis that T cell responses are generated in response to JE SA14-14-2 vaccination. The aim of this study is to characterize T cell responses to JE vaccine SA14-14-2 in healthy people, and to investigate differences in T cell responses between natural exposure, vaccination and disease.

Official Title
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A Prospective, Open Label Study of Human T Cell Responses to Live Attenuated Japanese Encephalitis Vaccine SA14-14-2

Conditions
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Japanese Encephalitis, Japanese Encephalitis Vaccine

Intervention / Treatment
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* Biological: Live attenuated Japanese encephalitis vaccine SA14-14-2


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: A male or female adult between 18 and 50 years of age. Written informed consent. Free of obvious health problems as established by medical history and history- directed physical examination before entering the study. Expected continuous residence in India during study period, without travel outside India An efficacious method of contraception must be used during the study for women of childbearing potential. Exclusion Criteria: Use of any investigational or non-registered drug or vaccine other than the study vaccine within 30 days preceding administration of SA14-14-2 vaccine, or planned use during the study period. Chronic administration of immunosuppressants or other immune-modifying drugs within a period of six months before vaccination or at any time during the study period. Any confirmed or suspected immunosuppressive or immunodeficient condition. A family history of congenital or hereditary immunodeficiency. Any antiviral drug therapy within a period of six months before vaccination or at any time during the study period. History of significant allergic disease or reactions likely to be exacerbated by any component of the study vaccine, especially allergic disease or reactions to any previous dose of any vaccine. History of having received JE vaccine, yellow fever vaccine, tick-borne encephalitis vaccine or experimental flavivirus vaccine. History of documented JE infection. Detectable anti JE or West Nile neutralizing antibodies in screening tests. Acute disease at the time of enrollment. Entry into the study may be deferred until the illness is resolved. Acute or chronic, clinically significant, pulmonary, cardiovascular, hepatic, neurological or renal functional abnormality, as determined by history and physical or laboratory examination that is not controlled by drugs. Administration of immunoglobulins and/or any blood products within the three months preceding administration of vaccine, or planned administration during the study period. Seropositive for HIV, HCV or HbsAg. Lactation, pregnancy or intention to get pregnant. History of excessive alcohol consumption, drug abuse or significant psychiatric illness. Any other condition that in the opinion of the investigator would pose a health risk to the participant or interfere with the evaluation of the vaccine.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vaccine<br>Single dose live attenuated Japanese encephalitis vaccine SA14-14-2 | Biological: Live attenuated Japanese encephalitis vaccine SA14-14-2<br>* Live attenuated Japanese encephalitis vaccine SA14-14-2<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of T Lymphocyte Responses to Live Attenuated JE SA-14-14-2 Vaccine at Week 2. | Interferon gamma (IFNγ) spot forming cells (SFC)/million peripheral blood mononuclear cells (PBMC) at week 2 (peak response) | Week 1, week 2, week 4, week 8, 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neutralizing Antibody Titres to Live Attenuated JE SA-14-14-2 Vaccine at Week 4 Post Vaccination. | Neutralizing antibody titres (measured by 50% Plaque reduction neutralisation titre (PRNT50)) at 4 weeks post vaccination | 4 weeks | 
| Number of Participants Reporting Adverse Events (Graded in Severity 1-4). |  | one month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Japanese encephalitis, Japanese encephalitis vaccine, T lymphocyte, Immune response