Serine protease P er a 10 from P eriplaneta americana bias dendritic cells towards type 2 by upregulating CD 86 and low IL ‐12 secretions

BACKGROUND: Serine protease activity of Per a 10 from Periplaneta americana induces airway inflammation and systemic Th2 response towards self and bystander allergen. OBJECTIVE: In the present study the effect of proteolytic activity of Per a 10 allergen on dendritic cells (DCs) polarization and consequent T cell response was investigated. METHODS: Non-atopic subjects with no family history of asthma/allergy were recruited for the study. CD14(+) peripheral blood monocytes were purified, differentiated to immature DCs and stimulated with proteolytically active/inactivated native or recombinant Per a 10. DCs phenotype was analysed with flow cytometry and antigen presenting function assessed by co-culturing with autologous CD4(+) T cells. Cytokine levels were determined using ELISA. RESULTS: Immature DCs differentiated into mature CD14(-)CD83(+)HLA-DR(+) cells after incubating with proteolytically active/inactivated or recombinant Per a 10. Proteolytically active Per a 10 induced significant CD86 up-regulation on DCs compared to inactivated or recombinant Per a 10 lacking enzymatic activity. Proteolytic activity of Per a 10 showed dose-dependent effect on expression of CD80, CD86, CD83, CD1a and HLA-DR. However, no significant differences were observed phenotypically in active or inactive forms except for CD86. Active Per a 10 stimulated DCs secreted significantly low IL-12 (P < 0.01) and high IL-6, compared to inactive forms of Per a 10. Naive CD4(+) T cells primed with active Per a 10 pulsed DCs also secreted significantly less IL-12 (P < 0.01) and high IL-4, IL-5 plus IL-6 (P < 0.01); in contrast to DCs pulsed with inactivated or recombinant Per a 10. CONCLUSION AND CLINICAL RELEVANCE: Proteolytic activity of Per a 10 modulates DCs towards type 2 by CD86 up-regulation, high IL-6 and reduced IL-12 secretions. Proteolytically inactive Per a 10 can be further explored for immunotherapy.