SARS-CoV-2 infection and vaccination elicit distinct pharyngeal mucosal B cell responses in children
- Qin Xu
- Lihong Shi
- Liya Wang
- Foo Cheung
- Aparna Kotekar
- Galina Koroleva
- Elizabeth Rice
- Richard Apps
- Justin Lack
- Craig Martens
- Iyadh Douagi
- Can Liu
- Juraj Kabat
- Hengameh Behzadpour
- Lela Kardava
- Tovah E. Markowitz
- Margery Smelkinson
- Kenneth B. Hoehn
- Clarisa M. Buckner
- Dominic P. Golec
- Lorenza Bellusci
- Gabrielle Grubbs
- Sara Pourhashemi
- Juanjie Tang
- Asya Khleborodova
- Martha Kirby
- Rachel Sparks
- Andrew J. Martins
- John S. Tsang
- Susan Moir
- Surender Khurana
- Pamela Mudd
- Pamela L. Schwartzberg
- Kalpana Manthiram
2026-05-22
Mucosal immunity is an important correlate of protection against respiratory infections such as SARS-CoV-2. Comparing B cell responses to vaccines and infection at relevant mucosal sites may provide unique and important insights into tissue immunity. Here, we characterize antigen-specific B cells in the tonsils, adenoids, and peripheral blood of children who had been infected with SARS-CoV-2 or vaccinated with SARS-CoV-2 mRNA vaccines. SARS-CoV-2-specific switched memory B cells (B SM ) are found in the pharyngeal lymphoid tissues and blood after vaccination or infection. However, infection generates a higher proportion of IgA + B SM and CXCR3 + CD21 + B SM . CXCR3 + CD21 + B SM show distinct spatial localization, greater clonal expansion and increased propensity for plasma cell differentiation compared to their CXCR3 - counterparts, accompanied by persistent activation of innate and T follicular helper cells in the tissues. Our data provide evidence for tissue-specific B cell memory after either SARS-CoV-2 vaccination or infection, but with distinct characteristics that can influence the quality, durability, and localization of immunity.