Ioanna Papadatou (Greece)
National and Kapodistrian University of Athens, 'Agia Sophia' Children's Hospital
1st Department of Pediatrics, Immunobiology and Vaccinology Research Laboratory
Ioanna earned her Medical Degree in 2009 (Cum Laude) and her PhD in 2015 (Summa Cum Laude) from Athens Medical School, NKUA (Monograph: Memory B cell response to pneumococcal vaccination in asplenic patients). Since the completion of her PhD she has an continuous engagement in pediatric infectious diseases and vaccinology research. In parallel with her research work, she has completed her clinical training in Pediatrics both in the UK (2012-2014) and Greece(2016-2019). For her post-doctoral research, she has been awarded a Small Grant Award by ESPID(2015-2016) for her work on vaccine-induced memory T cells; the Robert Austrian Research Award for pneumococcal Vaccinology (2016) & an Early Career Grant (2020)for her work on vaccine-induced memory B cells and most recently the ESPID Fellowship Award (2020) for her work on Systems Analysis of the immune response to pneumococcal vaccination- including transcriptional profiling- in collaboration with Emory University, USA. She has authored several peer-reviewed scientific papers and presented in numerous international meetings. Joanna is married and is a mum of two boys.

Presenter of 1 Presentation

 Conference Calendar

O011 - ESTABLISHMENT OF SEROTYPE-SPECIFIC IMMUNOLOGICAL MEMORY BY DIFFERENT INFANT IMMUNIZATION SCHEDULES WITH PCV13 (ID 498)

Session Name
0320 - Parallel Session 02: New Vaccine Products and Vaccination Strategies (ID 24)
Session Type
Parallel Session
Date
Mon, 20.06.2022
Session Time
15:20 - 16:35
Room
Grand Ballroom West
Presenter
Lecture Time
15:55 - 16:05

Abstract

Background

Vaccine-induced memory B cell(MBC) composition is important for vaccine effectiveness, since different MBC subsets have distinct roles in the duration and magnitude of protection. Here, we compare the immunogenicity and phenotype of immunological memory induced by the three commonly used PCV13 infant immunisation schedules (3+0,2+1,3+1).

Methods

Thirty infants(aged 2-15 months) were stratified into 3 groups: 3+0(n=14), 2+1(n=7), 3+1(n=9). Peripheral Blood Monocyte Cells(PBMCs) and serum were collected before and 28days after the last dose of each schedule. Antibodies were assessed by ELISA. Pneumococcal serotype(PS)-specific IgM, switched Ig(swIg) and extra-germinal center(extra-GC) MBCs were enumerated with Flow Cytometry.

Results

All schedules yield protective antibody titers. Higher levels are achieved when the third dose is given as a booster [GMT(mg/dl) 3+0 vs 2+1: PS1 7.9 vs 19.5 p=.24, PS3 1.7 vs 3.8 p<.05, PS9V 13.6 vs 31.2 p=.12]. Regarding PS-specific MBC response to booster, 2-dose priming(2+1) leads to expansion of the swIg MBC pool (26% pre- vs 45% post-booster, p<.05), whereas 3-dose priming(3+1) to higher IgM MBCs (13% pre vs 29% post-booster,p=.28). PS-specific extra-GC MBCs in group 3+0 were higher after the last dose compared to the other groups [79% vs 46% (2+1) vs 54% (3+1),p<.05].

Conclusions

The number of primary doses affects the phenotype of produced MBCs, suggesting long-term effects on the induced protection as, upon antigen restimulation, IgM MBCs maintain the MBC pool whereas swIg MBCs differentiate into plasma cells. At six months of age (after 3+0 schedule), subjects were unable to establish GC-derived MBCs implying an age-related effect on germinal center formation following vaccination.

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