Functional Consequences of T-bet Expression in Flu-specific Memory B Cells After Live Attenuated Influenza Vaccine (LAIV)

Status

Completed

Phases

Early Phase 1

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT04080245

Acronym

LAIV

Enrollment

Registered

2019-09-06

Start date

2019-11-15

Completion date

2025-06-01

Last updated

2025-06-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Influenza, Human

Keywords

Vaccine, Influenza, Efficacy

Brief summary

As yet the investigators do not understand if there are biomarkers of immune protection after the Flumist or Live Attenuated Flu Vaccine (LAIV). Here the investigators test the hypothesis that the T-bet expressing fraction of flu-specific B cells after live attenuated influenza vaccination also serves as an early biomarker of long-lived antibody responses after vaccination. In this study the investigators will be providing the LAIV to up to 10 healthy subjects and assaying their immune response and then providing the intramuscular influenza vaccination and testing to see if the immune protection after the LAIV also protects after the intramuscular influenza vaccination. Update: We have amended this protocol to study the antigen-specific B cell populations that circulate after LAIV or IIV prime and LAIV or IIV boost.

Detailed description

Previously (1) the investigators established that a fluorochrome labeled reagent with the influenza antigen hemagglutinin accurately identified flu-specific B cells after inactivated influenza vaccination and we established that a subset of these flu-specfiic B cells that express the lineage defining master transcriptional regulator, T-bet, correlate with long lived antibody responses. As yet the investigators do not understand if there are biomarkers of immune protection after the Flumist or Live Attenuated Flu Vaccine (LAIV). Here the investigators test the hypothesis that the T-bet expressing fraction of flu-specific B cells after live attenuated influenza vaccination also serves as an early biomarker of long-lived antibody responses after vaccination. In this study the investigators will be providing the LAIV to up to 10 healthy subjects and assaying their immune response and then providing the intramuscular influenza vaccination and testing to see if the immune protection after the LAIV also protects after the intramuscular influenza vaccination. Update: We have amended this protocol to study the antigen-specific B cell populations that circulate after LAIV or IIV prime and LAIV or IIV boost.

Interventions

BIOLOGICALTreatment Group Live Attenuated Flu Vaccine (LAIV)

We will administer LAIV once as a vaccine prime and IIV once as a vaccine boost with serial weekly blood draws for a month to validate a biomarker of LAIV efficacy.

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

BASIC_SCIENCE

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 50 Years

Healthy volunteers

Yes

Inclusion criteria

* Missed getting the flu vaccine in the last year * No history of reactive airway disease * No history of allergy to LAIV * No history of allergy to IIV * Self-identify as healthy without an immunocompromising condition defined as cancer, autoimmune disease, organ transplant or receipt of steroids.

Exclusion criteria

* History of reactive airway disease * History of allergy to LAIV or IIV * Do not self-identify as healthy

Design outcomes

Primary

Measure	Time frame	Description
Outcome Measure: Participants with a positive T-bet expressing Flu-specific B cell subtype	Baseline	The investigators will perform a blood test on lymphocytes from circulating blood.

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026