Analysis of Bone Marrow and Blood B Cell Immune Responses to Influenza Vaccination

Study Overview
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Brief Summary
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This was a Phase IV open label and single arm study, with the aim of enrolling up to 55 healthy males and non-pregnant females in a single site, age 18-49 years old, inclusive. This study was designed to assess the humoral response to influenza vaccination and the longevity of humoral immunity to influenza vaccination in healthy adults. Total enrollment was 27 participants. This was a multi-year study. After one year of participation, participants were offered the opportunity to participate in the study for up to 3 consecutive years, provided eligibility criteria was met each year. Participants who elected to continue in the study after first year of participation were rescreened to verify continued eligibility and re-consented prior to subsequent participation. The primary study objective was to investigate the longevity of humoral immunity to influenza virus in humans. Note: Due to the Coronavirus Disease of 2019 (COVID-19) pandemic, all non-essential research was halted in mid-March 2020. New enrollments were placed on hold for this study. Follow-up visits were also halted, which impacted the timing of participants' subsequent follow-up visits. Participant visits for Day 7 and Day 14 were not impacted. For this study, there were participants whose Day 28 and Day 90 visits were impacted by the temporary halting of non-essential research studies. As such, a request was submitted to the Emory University Institutional Review Board to extend the missed visit windows for the Day 28 and Day 90 visits for a maximum of up to 180 days, to ensure that ample time was available to bring participants back for their missed visits. Enrollment for this study ended on March 31, 2020, before research activities could resume at Emory.

Detailed Description
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This was a Phase IV open label and single arm study, with the aim of enrolling up to 55 healthy males and non-pregnant females in a single site, age 18-49 years old, inclusive. This study was designed to assess the humoral response to influenza vaccination and the longevity of humoral immunity to influenza vaccination in healthy adults. Total enrollment was 27 participants. The laboratory technique used in this study characterized persistence and clonotype of antigen specific B-cells and plasmablasts in blood and bone marrow. Enrolled participants received licensed seasonal inactivated influenza vaccine (administered as a part of the study). The vaccine was administered according to the package insert, and study participants donated serial samples of blood and bone marrow aspirate for immunology monitoring. Safety was assessed from the time of study enrollment through the last study visit, via monitoring of vital signs, change in health status, and targeted physical exam with safety labs prior to each bone marrow aspirate procedure. Repeated measurements of humoral immunity were obtained at 7 days, 14 days, 28 days, 90 days and at one year post-vaccination to assess the magnitude, clonal diversity and persistence of B-cell responses to influenza vaccination. This was a multi-year study. After one year of participation, participants were offered the opportunity to participate in the study for up to 3 consecutive years, provided eligibility criteria was met each year. Participants who elected to continue in the study after first year of participation were rescreened to verify continued eligibility and re-consented prior to subsequent participation. Re-enrolling participants received new subject identifiers and will count towards the total enrollment number for subsequent years of participation. A separate subject record will be maintained each year a subject re-enrolls in the study. Enrollment for the next year will begin with the availability of the seasonal flu vaccine. For participants who elect to re-enroll in the study, the Day 365 visit (+/- 3 month window) would also be the Day 0 visit for the subsequent year. The primary study objective is to investigate the longevity of humoral immunity to influenza virus in humans. The secondary study objective is the longitudinal tracking of vaccine-induced B cell responses with special emphasis on broadly neutralizing HA (hemagglutinin) stem-reactive responses. Note: Due to the Coronavirus Disease of 2019 (COVID-19) pandemic, all non-essential research was halted in mid-March 2020. New enrollments were placed on hold for this study. Follow-up visits were also halted, which impacted the timing of participants' subsequent follow-up visits. Participant visits for Day 7 and Day 14 were not impacted. For this study, there are participants whose Day 28 and Day 90 visits were impacted by the temporary halting of non-essential research studies. As such, a request was submitted to the Emory University Institutional Review Board to extend the missed visit windows for the Day 28 and Day 90 visits for a maximum of up to 180 days, to ensure that ample time was available to bring participants back for their missed visits. Enrollment for this study ended on March 31, 2020, before research activities could resume at Emory.

Official Title
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Analysis of Bone Marrow and Blood B Cell Immune Responses to Influenza Vaccination

Conditions
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Influenza, Influenza Immunisation

Intervention / Treatment
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* Biological: Influenza Virus Vaccine Inactivated


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or non-pregnant female subjects between 18 and 49 years of age (inclusive). Subjects capable of providing written informed consent prior to initiation of any study procedures. Subjects able to understand and comply with planned study procedures and be available for all study visits. Safety labs: White blood cell count (WBC), within reference range of lower limit of normal of 4,000 per microliter (uL), and upper limit of normal of 10,000 per microliter (uL). Hemoglobin, within reference range of lower limit of normal of 11.4 grams per deciliter (gm/dL) and upper limit of normal of 16.1 grams per deciliter (gm/dL). Hematocrit, within reference range of lower limit of normal of 33.3 percent and an upper limit of normal of 46.5 percent. Platelet Count, within reference range of lower limit of normal of 150,000 per microliter (uL) and upper limit of normal of 400,000 per microliter (uL). Prothrombin Time (PT/INR), PT below or equal to the upper limit of normal of 13.1 seconds; International Normalized Ratio (INR) within normal reference range of less than 1.5 (normal range for non-anti-coagulated patients). Creatinine within reference range of lower limit of normal of 0.4 milligrams per deciliter (mg / dL) and upper limit of normal of 1.2 milligrams per deciliter (mg / dL). Potassium, within reference range of lower limit of normal of 3.6 millimolar (mM) and upper limit of normal of 5.1 millimolar (mM). Heart rate > / = 55 to < / = 100 per minute. Systolic blood pressure > / = 90 to < / = 150 millimeters of mercury (mmHg). Diastolic blood pressure < 90 millimeters of mercury (mmHg). Oral temperature < 100 degrees Fahrenheit. Respirations even, unlabored, and > 10 / minute to < 20 / minute. Female subjects of child bearing potential must have a negative urine pregnancy test at the screening visit, enrollment visit and prior to subsequent bone marrow aspirate procedures. Female subjects of childbearing potential must agree to practice abstinence, use a barrier method of birth control, or use an U.S. Food and Drug Administration (FDA) approved form of birth control. Subjects who have not received seasonal flu vaccine for the current year (September - June). Exclusion Criteria: If female, active pregnancy or breast-feeding or plans to become pregnant during study participation. Subject report of having any medical disease or condition that, in the opinion of the site principal investigator or appropriate sub-investigator, is a contraindication to study participation. This includes any acute or chronic medical disease or condition, defined as persisting 3 months (defined as 90 days) or longer, that would place the subject at an unacceptable risk of injury, render the subject unable to meet the requirements of the protocol, or may interfere with the evaluation of responses or the subject's successful completion of this study. Subject report of taking anticoagulants, or long-term (greater than 14 days) systemic steroids or other immunosuppressive medications. Subject report of known allergy to lidocaine. Subject report of known hypersensitivity or allergy to eggs, egg or chicken protein, report of allergy to components of the study vaccine or other components of the study vaccine. Subject report of known latex allergy. Subject report of a history of severe reactions following previous immunization with licensed or unlicensed influenza virus vaccines. Subject report of a history of Guillain-Barre syndrome. Subjects who believe they cannot tolerate the bone marrow aspirations without sedation. Subjects with an active infection or that have an acute illness within 72 hours prior to study vaccination. Subject having had an acute illness which is nearly resolved with only minor residual symptoms remaining is allowable if, in the opinion of the site principal investigator or appropriate sub-investigator, the residual symptoms will not interfere with the ability to assess safety parameters as required by the protocol. Subjects who are participating in another clinical trial involving the use of investigational agents or vaccines.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 49 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: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Influenza Virus Vaccine Inactivated<br>All study participants received licensed inactivated influenza vaccine intramuscularly (IM) on Day 0. | Biological: Influenza Virus Vaccine Inactivated<br>* A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season. All participants received vaccine intramuscularly (IM) on Day 0.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Influenza-specific Antibody Secreting Cells (ASC) Present in the Blood | Blood Immunoglobulin G (IgG) ASC specific for the seasonal influenza vaccine were measured by enzyme-linked immunosorbent spot (ELISPOT) using vaccine-coated plates. Numbers of influenza-specific ASC per million peripheral blood mononuclear cells are reported. | Day 7 | 
| Number of Influenza-specific Antibody Secreting Cells (ASC) Present in the Bone Marrow | Influenza-specific IgG ASC and total IgG ASC were measured in bone marrow samples by ELISPOT using plates coated with influenza vaccine or total IgG capture antibody. Influenza-specific bone marrow IgG ASC numbers are expressed as a percentage of the total bone marrow IgG ASC number. | Day 0 | 
| Number of Influenza-specific Antibody Secreting Cells (ASC) Present in the Bone Marrow | Influenza-specific IgG ASC and total IgG ASC were measured in bone marrow samples by ELISPOT using plates coated with influenza vaccine or total IgG capture antibody. Influenza-specific bone marrow IgG ASC numbers are expressed as a percentage of the total bone marrow IgG ASC number. | Day 28 | 
| Number of Influenza-specific Antibody Secreting Cells (ASC) Present in the Bone Marrow | Influenza-specific IgG ASC and total IgG ASC were measured in bone marrow samples by ELISPOT using plates coated with influenza vaccine or total IgG capture antibody. Influenza-specific bone marrow IgG ASC numbers are expressed as a percentage of the total bone marrow IgG ASC number. | Day 365 | 
| Number of Influenza-specific Memory B Cells Present in the Blood | Influenza-specific memory B cells were assayed by ELISPOT after polyclonal stimulation of peripheral blood mononuclear cells to generate ASC. The influenza-specific memory B cell frequencies are reported as the percentage of IgG secreting cells found in the stimulated cultures. | Day 0 | 
| Number of Influenza-specific Memory B Cells Present in the Blood | Influenza-specific memory B cells were assayed by ELISPOT after polyclonal stimulation of peripheral blood mononuclear cells to generate ASC. The influenza-specific memory B cell frequencies are reported as the percentage of IgG secreting cells found in the stimulated cultures. | Day 28 | 
| Number of Influenza-specific Memory B Cells Present in the Blood | Influenza-specific memory B cells were assayed by ELISPOT after polyclonal stimulation of peripheral blood mononuclear cells to generate ASC. The influenza-specific memory B cell frequencies are reported as the percentage of IgG secreting cells found in the stimulated cultures. | Day 365 | 
| Number of Subjects Who Initially Seroconverted and Maintained Seroconversion at 1 Year Post Vaccination | Initial seroconversion is defined as having a pre-vaccination (day 0) hemagglutination inhibition (HAI) titer < 1:40 against a particular strain and a day 28 post-vaccination titer > / = 1:40 against the same strain OR a pre-vaccination HAI titer >1:40 and an increase in titer of at least 4-fold on day 28 relative to day 0. Maintenance of seroconversion in those who initially seroconverted is defined as maintaining an HAI titer >/= 40 at 1 year in those with day 0 titers < 40 OR maintaining a >/= 4-fold increase in HAI titer at one year compared to day 0. HAI assays were performed using 0.75% guinea pig red blood cells and virus stocks matched to the strains in the vaccines received by each donor. | Day 365 | 
| Number of Subjects Achieving Seroconversion to Each of the Strains in the Vaccine | Seroconversion defined as having a pre-vaccination (day 0) hemagglutination inhibition (HAI) titer < 1:40 against a particular strain and a Day 28 post-vaccination titer > / = 1:40 against the same strain OR a pre-vaccination HAI titer >1:40 and an increase in titer of at least 4-fold on day 28. HAI assays were performed using 0.75% guinea pig red blood cells and virus stocks matched to the strains in the vaccines received by each donor. | Day 28 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frequency of Hemagglutinin Stem Reactive Responses to Influenza Vaccine Among Blood Plasmablasts | Blood IgG ASC specific for the seasonal influenza vaccine were measured by ELISPOT using plates coated with chimeric hemagglutinin antigen containing the pandemic H1 stem domain fused to the head domain of an H9 influenza virus. Numbers of stem-specific ASC per million peripheral blood mononuclear cells are reported. | Day 7 | 
| Frequency of Hemagglutinin Stem Reactive Responses to Influenza Vaccine Among the Bone Marrow Plasma Cells | Influenza-specific IgG ASC and total IgG ASC were measured in bone marrow samples by ELISPOT using plates coated with H9 head/H1 stem chimeric hemagglutinin antigen or total IgG capture antibody. Stem-specific bone marrow IgG ASC numbers are expressed as a percentage of the total bone marrow IgG ASC number. | Day 365 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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HA (hemagglutinin) -specific plasmablasts, humoral immunity, influenza, memory B cells