Fungal pathogens elicit cytokine responses downstream of immunoreceptor tyrosine-based activation motif (ITAM)-coupled or hemiITAM-containing receptors and TLRs. The Linker for Activation of B cells/Non-T cell Activating Linker (LAB/NTAL) encoded by Lat2, is a known regulator of ITAM-coupled receptors and TLR-associated cytokine responses. Here we demonstrate that LAB is involved in anti-fungal immunity. We show that Lat2−/− mice are more susceptible to C. albicans infection than wild type (WT) mice. Dendritic cells (DCs) express LAB and we show that it is basally phosphorylated by the growth factor M-CSF or following engagement of Dectin-2, but not Dectin-1. Our data revealed a unique mechanism whereby LAB controls basal and fungal/pathogen-associated molecular patterns (PAMP)-induced nuclear β-catenin levels. This in turn is important for controlling fungal/PAMP-induced cytokine production in DCs. C. albicans- and LPS-induced IL-12 and IL-23 production was blunted inLat2−/− DCs. Accordingly, Lat2−/− DCs directed reduced Th1 polarization in vitro and Lat2−/−mice displayed reduced Natural Killer (NK) and T cell-mediated IFN-γ production in vivo/ex vivo. Thus our data define a novel link between LAB and β-catenin nuclear accumulation in DCs that facilitates IFN-γ responses during anti-fungal immunity. In addition, these findings are likely to be relevant to other infectious diseases that require IL-12 family cytokines and an IFN-γ response for pathogen clearance.
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Orr, Selinda J.; Burg, Ashley R.; Chan, Tim; Quigley, Laura; Jones, Gareth W.; Ford, Jill W.; Hodge, Deborah; Razzook, Catherine; Sarhan, Joseph; Jones-Hall, Yava L.; Whittaker, Gillian C.; Boelte, Kimberly C.; Lyakh, Lyudmila; Cardone, Marco; O'Connor, Geraldine M.; Tan, Cuiyan; Li, Hongchuan; Anderson, Stephen K.; Jones, Simon A.; Zhang, Weigo; Taylor, Philip R.; Trinchieri, Giorgio; and McVicar, Daniel W., "LAB/NTAL Facilitates Fungal/PAMP-induced IL-12 and IFN-γ Production by Repressing β-Catenin Activation in Dendritic Cells." (2013). Department of Comparative Pathobiology Faculty Publications. Paper 17.