Collagen V-induced nasal tolerance increase FOXp3 in systemic sclerosis model

Abstract

Objective: To evaluate FOXp3 expression in bronchus-associated lymphoid tissue (BALT) and correlate with the inflammatory process and collagen content in the lung tissue in an experimental model of scleroderma (SSc) after type V collagen (COL V)-induced nasal tolerance. Method: Female New Zealand rabbits (N=12) were immunized with 1 mg/ml of COL V in Freund’s adjuvant (IM). After 150 days, six immunized animals were nasally tolerated with COL V (25νg/day), during 60 days (IM-TOL). Animals (N=6) only tolerated served as control (CT). FOXP3 expression in BALT and inflammatory cells in pulmonary interstitium were evaluated by point counting method. Types I, III and V collagen gene expression were evaluated by Real-time PCR. Results: IM-TOL when compared to IM presented decreased lymphocytes, macrophages and monocytes and types I (p=0,002) and V (p=0,009) collagen mRNA expression in pulmonary tissue. T lymphocytes FOXp3 were expressed in 100 % of IM-TOL and 33,3 % of CT (p=0,03). Additionally, BALT was higher expressed in IM-TOL in relation to CT. Conclusion: COL V-induced nasal tolerance in SSc model induces FOXp3 regulatory T cells in BALT which can trigger an immune regulatory mechanism resulting in decreased inflammation and collagen expression. It suggests that COL V tolerance could be a promising therapeutic for human scleroderma treatment.