Poly(I:C)-Treated human langerhans cells promote the differentiation of CD4+ T cells producing IFN-gamma and IL-10.
Epidermal Langerhans cells (LCs) are the first dendritic cells to encounter skin pathogens. However, their function has recently been challenged, especially in the initiation of T-cell responses to viral antigens. We have previously reported that fresh immature human LCs express mRNA encoding TLR3. Here we analyze the response of highly purified human LCs to poly(I:C), a synthetic mimetic of viral dsRNA recognized by TLR3. We show that LCs exposed for 2 days to poly(I:C) under serum-free conditions up-regulated co-stimulatory molecules, a process associated with increased allostimulatory capacity. Furthermore, poly(I:C) significantly enhanced LC survival and induced them to produce CXCL10, IL-6, and IL-12 p40. Bioactive IL-12 p70, IL-1beta, IL-15, IL-18, and IL-23 were never detected, even after CD40 ligation. LC incubation in the presence of bafilomycin completely reversed the effect of poly(I:C) on LC phenotypic activation and survival, indicating that endosomal TLR3 is involved in this process. Most interestingly, we report here that poly(I:C)-treated LCs favored alloreactive CD4(+) T-cell differentiation toward a Th1 profile and concomitant differentiation of IL-10-producing CD4(+) T cells that might limit, at another time, the inflammatory response and subsequent tissue damage.
Furio
Laetitia
L
Université de Lyon, Lyon, EA 41-69, Laboratoire de Dermatologie, Pavillon R, Hôpital E. Herriot, Lyon, France.
Billard
Hermine
H
Valladeau
Jenny
J
Péguet-Navarro
Josette
J
Berthier-Vergnes
Odile
O
D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D016753:Interleukin-10 / Q000096:biosynthesis*; D018664:Interleukin-12 / Q000502:physiology; D053759:Interleukin-23 / Q000502:physiology; D007801:Langerhans Cells / Q000187:drug effects* / Q000502:physiology; D011070:Poly I-C / Q000494:pharmacology*; D051196:Toll-Like Receptor 3 / Q000502:physiology
D016207:Cytokines; D053759:Interleukin-23; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; D016753:Interleukin-10; D018664:Interleukin-12; D007371:Interferon-gamma; D011070:Poly I-C