It is currently not understood whether cigarette
smoke exposure facilitates sensitisation to
self-antigens and whether ensuing auto-reactive T cells drive
chronic obstructive pulmonary disease (
COPD)-associated pathologies.To address this question, mice were exposed to cigarette
smoke for 2 weeks. Following a 2-week period of rest, mice were challenged intratracheally with
elastin for 3 days or 1 month. Rag1-/- , Mmp12-/- , and Il17a-/- mice and neutralising
antibodies against active
elastin fragments were used for mechanistic investigations. Human GVAPGVGVAPGV/
HLA-A*02:01 tetramer was synthesised to assess the presence of
elastin-specific T cells in patients with
COPD.We observed that 2 weeks of cigarette
smoke exposure induced an
elastin-specific T cell response that led to neutrophilic airway
inflammation and mucus hyperproduction following
elastin recall challenge. Repeated
elastin challenge for 1 month resulted in
airway remodelling, lung function decline and airspace enlargement.
Elastin-specific T cell recall responses were dose dependent and memory lasted for over 6 months. Adoptive T cell transfer and studies in T cells deficient Rag1-/- mice conclusively implicated T cells in these processes. Mechanistically, cigarette
smoke exposure-induced
elastin-specific T cell responses were
matrix metalloproteinase (MMP)12-dependent, while the ensuing immune inflammatory processes were
interleukin 17A-driven. Anti-
elastin antibodies and T cells specific for
elastin peptides were increased in patients with
COPD.These data demonstrate that MMP12-generated
elastin fragments serve as a
self-antigen and drive the cigarette
smoke-induced autoimmune processes in mice that result in a
bronchitis-like phenotype and airspace enlargement. The study provides proof of concept of cigarette
smoke-induced autoimmune processes and may serve as a novel mouse model of
COPD.