Tissue resident memory B cells established in lungs in allergic asthma

Abstract

Abstract Allergic asthma is a disease driven by the adaptive immune system in the lungs. B cells play a critical role during the allergen sensitization process by producing IgE and possibly through antigen presentation. While most current research has focused on the role of CD4+ tissue resident memory (TRM) cells, it is not known whether TRM B cells exist within the lungs and what role they might play. To investigate this question, we sensitized mice to house dust mite (HDM) intranasally for three weeks to induce asthmatic symptoms. We in vivo labeled mice with circulating fluorescent anti CD45 mAb and assessed the lung B cells’ susceptibility to labeling. We found that B cells, that are resistant to in vivo labeling, are a major population of lung lymphocytes following HDM sensitization. We were further able to detect these non-circulating B cells in the lungs as late as 10 weeks after treatment in sensitized mice. Furthermore, these cells were found in the same anatomic locations as CD4+ TRM cells and underwent expansion during HDM challenge. These data suggest that B cells do form a tissue resident population in the lungs and that these cells are involved in allergic asthmatic responses. This resident memory population of B cells are also locally activated upon allergen rechallenge. Whether these B cells are reactivated by HDM-derived antigens or by T cell-derived cytokines is yet to be determined.