Qualitative monitoring of SARS-CoV-2 mRNA vaccination in humans using droplet microfluidics
Matteo Broketa, Aurélien Sokal, Michael Mor, Pablo Canales-Herrerias, Angga Perima, Annalisa Meola, Ignacio Fernández, Bruno Iannascoli, Guilhem Chenon, Alexis Vandenberghe, Laetitia Languille, Marc Michel, Bertrand Godeau, Sébastien Gallien, Giovanna Melica, Marija Backovic, Felix A. Rey, Jean Baudry, Natalia T. Freund, Matthieu Mahévas, Pierre Bruhns
Matteo Broketa, Aurélien Sokal, Michael Mor, Pablo Canales-Herrerias, Angga Perima, Annalisa Meola, Ignacio Fernández, Bruno Iannascoli, Guilhem Chenon, Alexis Vandenberghe, Laetitia Languille, Marc Michel, Bertrand Godeau, Sébastien Gallien, Giovanna Melica, Marija Backovic, Felix A. Rey, Jean Baudry, Natalia T. Freund, Matthieu Mahévas, Pierre Bruhns
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Resource and Technical Advance Immunology Vaccines

Qualitative monitoring of SARS-CoV-2 mRNA vaccination in humans using droplet microfluidics

Abstract

SARS-CoV-2 mRNA vaccination generates protective B cell responses targeting the SARS-CoV-2 spike glycoprotein. Whereas anti-spike memory B cell responses are long lasting, the anti-spike humoral antibody response progressively wanes, making booster vaccinations necessary for maintaining protective immunity. Here, we qualitatively investigated the plasmablast responses by measuring from single cells within hours of sampling the affinity of their secreted antibody for the SARS-CoV-2 spike receptor binding domain (RBD) in cohorts of BNT162b2-vaccinated naive and COVID-19–recovered individuals. Using a droplet microfluidic and imaging approach, we analyzed more than 4,000 single IgG-secreting cells, revealing high interindividual variability in affinity for RBD, with variations over 4 logs. High-affinity plasmablasts were induced by BNT162b2 vaccination against Hu-1 and Omicron RBD but disappeared quickly thereafter, whereas low-affinity plasmablasts represented more than 65% of the plasmablast response at all time points. Our droplet-based method thus proves efficient at fast and qualitative immune monitoring and should be helpful for optimization of vaccination protocols.

Authors

Matteo Broketa, Aurélien Sokal, Michael Mor, Pablo Canales-Herrerias, Angga Perima, Annalisa Meola, Ignacio Fernández, Bruno Iannascoli, Guilhem Chenon, Alexis Vandenberghe, Laetitia Languille, Marc Michel, Bertrand Godeau, Sébastien Gallien, Giovanna Melica, Marija Backovic, Felix A. Rey, Jean Baudry, Natalia T. Freund, Matthieu Mahévas, Pierre Bruhns

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Figure 3

DropMap for the detection of anti-BA.1 IgG–secreting cells.

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DropMap for the detection of anti-BA.1 IgG–secreting cells. (A) Example ...
(A) Example of droplets containing no mAb (top) or 5 nM TAU-1109 mAb (bottom), showing fluorescence relocation of Omicron BA.1 RBD–Alexa Fluor 555 (yellow, left) and anti–IgG F(ab′)2–Alexa Fluor 647 (red, right). Scale bars: 50 μm. (B) In-droplet mAb (TAU-1109) measurement of fluorescence relocation at 0, 1.25, 2.5, and 5 nM in droplet concentration performed in triplicate. Each dot represents the mean of a triplicate measure. Linear regression is represented, with 95% confidence intervals in gray, n = 3. (C) Omicron affinity reference curve calibrated with anti-RBD mAbs with known KD for BA.1 RBD and DropMap slope determined from method exemplified in B. (D) Affinities for SARS-CoV-2 RBD of a single IgG-SC (n = 181) from naive and recovered individuals using either Hu-1 (blue) or BA.1 (orange) RBD. Each dot represents a value from a single cell. Medians are shown. (E) Frequencies of Hu-1–specific (top) or BA.1-specific (bottom) IgG-SCs classified into low (yellow), medium (orange), high affinity (red), or no detectable binding (white), among total IgG-SCs, with total numbers indicated in center.