Virology

Antibody

Lymphatic system

Acquired immune system

Tonsillectomy

Immune system

Palatine tonsil

Virus

Biology

Tonsil

Adenoidectomy

Immunity

Memory B cell

Germinal center

Pathology

Immunology

B cell

Medicine

Nature Immunology

Most studies of adaptive immunity to SARS-CoV-2 infection focus on peripheral blood, which may not fully reflect immune responses at the site of infection. Using samples from 110 children undergoing tonsillectomy and adenoidectomy during the COVID-19 pandemic, we identified 24 samples with evidence of previous SARS-CoV-2 infection, including neutralizing antibodies in serum and SARS-CoV-2-specific germinal center and memory B cells in the tonsils and adenoids. Single-cell B cell receptor (BCR) sequencing indicated virus-specific BCRs were class-switched and somatically hypermutated, with overlapping clones in the two tissues. Expanded T cell clonotypes were found in tonsils, adenoids and blood post-COVID-19, some with CDR3 sequences identical to previously reported SARS-CoV-2-reactive T cell receptors (TCRs). Pharyngeal tissues from COVID-19-convalescent children showed persistent expansion of germinal center and antiviral lymphocyte populations associated with interferon (IFN)-γ-type responses, particularly in the adenoids, and viral RNA in both tissues. Our results provide evidence for persistent tissue-specific immunity to SARS-CoV-2 in the upper respiratory tract of children after infection. Manthiram and colleagues analyze the peripheral blood, tonsils and adenoids in children undergoing tonsillectomy or adenoidectomy and find evidence of continued tissue-specific immunity to SARS-CoV-2 and viral RNA persistence weeks to months after acute infection.

Adaptive immune responses to SARS-CoV-2 persist in the pharyngeal lymphoid tissue of children