The Intestine-lung Trafficking of Memory-like Group 2 Innate Lymphoid
Cells Orchestrates Asthma Relapse
Abstract
Background: Recent works imply that immune memory might be
expanded to group 2 innate lymphoid cells (ILC2s), but the cellular and
molecular bases are largely unknown. Here, we investigated the memory
and migrating properties of Lin -KLRG1
+IL-17RB + ILC2s (herein referred as
mILC2s) and their contribution to asthma relapse. Methods:
Clinical asthmatic subjects and HDM-induced mice asthma models were
applied to investigate the memory-like characteristics of mILC2s
including greater effector cytokine-producing potential and in
vivo persistence. Parabiosis pairs of CD45.1 + and
CD45.2 + mice were employed to determine whether
mILC2s were circulating cells. Adoptive transplantation was performed to
analyze the origin of the mILC2s accumulated in airway upon asthma
relapse. CCR9 and S1P signaling blockade were used to confirm the
migration of mILC2s during different asthma phases by In vivo
imaging. KLRG1 neutralization was utilized to analyze the role of mILC2s
in asthma relapse on Rag1 -/- mice.
Results: mILC2s persisted in vivo and retained the
potency of producing IL-13 and re-inducing allergic responses.
Critically, parabiosis study and in vivo imaging showed that the
vast majority of mILC2s migrated to and resided in small intestine
during asthma remission, and subsequently moved to airway upon
re-encountering antigens, regulated by CCR9 and S1P signaling. Blockade
of S1P signaling markedly limited secondary exposure-induced airway
inflammation. Furthermore, KLRG1 neutralization attenuated asthmatic
responses of Rag1 -/- mice, supporting a
pivotal role for mILC2s in mediating asthma relapse independent of
adaptive immune cells. Conclusion: mILC2s exhibit memory-like
and lung-small intestine migratory properties, which empowers them to
drive asthma relapse.