PhD Scientific Days 2025

Poster Session III. - K: Theoretical and Translational Medicine

Indications of Anti-PEG Memory-like B Cell Activity After mRNA-LNP COVID-19 Vaccination

Előadó neve

Facskó Réka, MSc

Neptun code

UN9JFD

Előadó munkahelye

Nanomedicine Research and Education Center, Department of Translational Medicine, Semmelweis University, Budapest, Hungary

Előadó telefonszáma

+36305771548

Előadó e-mail címe

facsko.reka@phd.semmelweis.hu

Az előadás címe

Indications of Anti-PEG Memory-like B Cell Activity After mRNA-LNP COVID-19 Vaccination

Szerző(k) neve és munkahelye

Réka Facskó^1,2,3, Tamás Mészáros^1,2,3, János Szebeni^1,3, Tibor Gergely Kozma^1,3

1: Nanomedicine Research and Education Center, Department of Translational Medicine, Semmelweis University, Budapest, Hungary
2: Heart and Vascular Center, Semmelweis University, Budapest, Hungary
3: SeroScience LCC, Budapest, Hungary

Bemutatás módja

Poszter

Szekció

Poster Session III. - K: Theoretical and Translational Medicine

Language of the presentation

English

Preferred session

Theoretical and Translational Medicine

Összefoglaló szövege

Since the introduction of PEG-containing mRNA-lipid nanoparticle (LNP)-based Covid-19 vaccines, several studies have independently reported a significant increase in anti-PEG IgM and IgG antibodies following vaccination with Spikevax, Comirnaty or both. According to current knowledge, both vaccines induce a thymus-independent type 2 (TI-2) immune response against PEG. While TI-2 responses are traditionally not associated with immunological memory, some data indicate that they may generate memory-like B cells capable of producing high-affinity antibodies upon re-exposure to PEG antigens.
In this study, we investigated the presence and reactivation potential of anti-PEG memory-like B cells in the peripheral blood of individuals who received LNP-based Covid-19 vaccines.
Freshly isolated PBMCs were analysed for unswitched memory B cells (CD19+/CD27+/IgM+), switched memory B cells (CD19+/CD27+/IgM-) and naive B cells (CD19+/CD27-/IgM+) using flow cytometry, assessing their ability to bind fluorescently labelled PEG molecules and PEG-containing liposomes. To evaluate reactivation potential, PBMCs were stimulated in vitro using specific (DSPE-PEG micelles, PEGylated liposomes) and nonspecific (TLR agonists and cytokines) activation signals. Anti-PEG antibody secretion was measured in culture supernatants at multiple time points by ELISA.
We found that PEG alone was insufficient to detect PEG-specific B cells, likely due to inadequate BCR cross-linking. However, liposome-based labelling allowed identification of B cells with potential PEG reactivity, although specificity could not be confirmed. Additionally, we established a method using a combination of nonspecific activation signals that induced measurable anti-PEG IgM secretion in 5-day culture supernatants.
Our results suggest that PEG-reactive memory-like B cells may persist post-vaccination and can be reactivated in vitro, potentially contributing to anti-PEG antibody production upon future PEG exposure. This reactivation could pose a risk of reduced therapeutic efficacy or even serious adverse immune reactions following administration of PEGylated drugs.
Project NO. 2023-2.1.2-KDP-2023-00016 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the KDP-2023 funding scheme.

University

Semmelweis University

Supervisor

Tibor Gergely Kozma

Publication of my abstract

I do not give consent to the publication of my abstract on the website of the congress.

phd.section.field

in doctoral studies after complex exam (PhD)

Kind

Szabad

Status

elfogadva

Accepted presentation method

poszter

Előadás fájl jóváhagyás

nem rendelkezett róla

Előadó

8004

Start

14:36

End

14:42