Journal Article

Induction of bronchus-associated lymphoid tissue is an early life adaptation for promoting human B cell immunity

Rybkina, Ksenia, Friedman, Lilach M., Meng, Wenzhao, Brusko, Todd M., Gray, Joshua, Matsumoto, Rei, Rosenfeld, Aaron M., Bradley, Marissa C., Atkinson, Mark A., Hertz, Tomer, Khamaisi, Muhammad, Sims, Peter A., Guyer, Rebecca S., Connors, Thomas J., Oppenheimer, Hanna, Levy, Lior, Hershberg, Uri, Farber, Donna L., Chen, David, Luning Prak, Eline T., Brusko, Maigan

2023

Overview

Infants and young children are more susceptible to common respiratory pathogens than adults but can fare better against novel pathogens like severe acute respiratory syndrome coronavirus 2. The mechanisms by which infants and young children mount effective immune responses to respiratory pathogens are unknown. Through investigation of lungs and lung-associated lymph nodes from infant and pediatric organ donors aged 0–13 years, we show that bronchus-associated lymphoid tissue (BALT), containing B cell follicles, CD4 + T cells and functionally active germinal centers, develop during infancy. BALT structures are prevalent around lung airways during the first 3 years of life, and their numbers decline through childhood coincident with the accumulation of memory T cells. Single-cell profiling and repertoire analysis reveals that early life lung B cells undergo differentiation, somatic hypermutation and immunoglobulin class switching and exhibit a more activated profile than lymph node B cells. Moreover, B cells in the lung and lung-associated lymph nodes generate biased antibody responses to multiple respiratory pathogens compared to circulating antibodies, which are mostly specific for vaccine antigens in the early years of life. Together, our findings provide evidence for BALT as an early life adaptation for mobilizing localized immune protection to the diverse respiratory challenges during this formative life stage. Young children frequently encounter respiratory pathogens that elicit immune responses in developing lungs. Farber and colleagues examine rare lung tissue samples obtained from pediatric organ donors and find age-dependent formation of bronchus-associated lymphoid tissue (BALT), which peaks at 3 years of age and dissipates thereafter. Profiling of BALT lymphocytes indicates that repertoire and functional differences exist between the lung, draining lymph nodes and circulating cells.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: 631/250/2152/2153/1982 / 631/250/347 / Adaptation / Adult / Antigens / B-Lymphocytes / Biomedical and Life Sciences / Biomedicine / Bronchi - pathology / Bronchus / CD4 antigen / Cell differentiation / Child / Child, Preschool / Children / Class switching / Coronaviruses / COVID-19 - pathology / Follicles / Germinal centers / Humans / Immunological memory / Immunology / Infant / Infants / Infectious Diseases / Lungs / Lymph Nodes / Lymphatic system / Lymphocytes / Lymphocytes B / Lymphocytes T / Lymphoid Tissue / Memory cells / Organ donors / Pathogens / Pediatrics / Respiratory diseases / Severe acute respiratory syndrome / Severe acute respiratory syndrome coronavirus 2 / Somatic hypermutation