IL-23-driven encephalo-tropism and Th17 polarization during CNS-inflammation in vivo.
IL-23 but not IL-12 is essential for the development of autoimmune tissue inflammation in mice. Conversely, IL-12 and IL-23 impact on the polarization of Th1 and Th17 cells, respectively. While both polarized T helper populations can mediate autoimmune inflammation, their redundancy in the pathogenesis of EAE indicates that IL-23 exerts its crucial influence on the disease independent of its T helper polarizing capacity. To study the impact of IL-23 and IL-12 on the behavior of encephalitogenic T cells in vivo, we generated BM-chimeric mice in which we can trace individual populations of IL-23 or IL-12 responsive T helper cells during EAE. We observed that T cells, which lack IL-12Rbeta1 (no IL-12 and IL-23 signaling), fail to invade the CNS and do not acquire a Th17 phenotype. In contrast, loss of IL-12 signaling prevents Th1 polarization but does not prevent T-cell entry into the CNS. The loss of IL-12R engagement does not appear to alter T-cell expansion but leads to their accumulation in secondary lymphoid organs. We found that IL-23 licenses T cells to invade the target tissue and to exert their effector function, whereas IL-12 is critical for Th1 differentiation, but does not influence the pathogenic capacity of auto-reactive T helper cells in vivo.
Gyülvészi
Gabor
G
Department of Pathology, Institute of Experimental Immunology, University Hospital of Zürich, Switzerland.
Haak
Stefan
S
Becher
Burkhard
B
D000818:Animals; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002490:Central Nervous System / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D016899:Interferon-beta / Q000378:metabolism; D020381:Interleukin-17 / Q000378:metabolism*; D053759:Interleukin-23 / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D018123:Receptors, Interleukin / Q000235:genetics / Q000378:metabolism; D053707:Receptors, Interleukin-12 / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism / Q000473:pathology
D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D018398:Homeodomain Proteins; D020381:Interleukin-17; D053759:Interleukin-23; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; C528688:interleukin-23 receptor, mouse; C064658:RAG-1 protein; D016899:Interferon-beta