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The expanding number of rare immunodeficiency syndromes offers an opportunity to understand key genes that support immune defense against infectious diseases. However, analysis of these in patients is complicated by their treatments and comorbid infections, requiring the use of mouse models for detailed investigations. We developed a mouse model of DOCK2 immunodeficiency and herein demonstrate that these mice have delayed clearance of herpes simplex virus type 1 (HSV-1) infections. We also uncovered a critical, cell-intrinsic role of DOCK2 in the priming of antiviral CD8+ T cells and in particular their initial expansion, despite apparently normal early activation of these cells. When this defect was overcome by priming in vitro, DOCK2-deficient CD8+ T cells were surprisingly protective against HSV-1 disease, albeit not as effectively as wild-type cells. These results shed light on a cellular deficiency that is likely to impact antiviral immunity in DOCK2-deficient patients. [ABSTRACT FROM AUTHOR]

Cytoplasmic caspase-11 (also known as caspase-4) defines the non-canonical inflammasome that is activated by various Gram-negative bacterial infections and causes infected cells to die by pyroptosis (1-4). Caspase-11 also triggers [...], Intracellular lipopolysaccharide from Gram-negative bacteria including Escherichia coli, Salmonella typhimurium, Shigella flexneri, and Burkholderia thailandensis activates mouse caspase-11, causing pyroptotic cell death, interleukin-1β processing, and lethal septic shock. How caspase-11 executes these downstream signalling events is largely unknown. Here we show that gasdermin D is essential for caspase-11-dependent pyroptosis and interleukm-1β maturation. A forward genetic screen with ethyl-N-nitrosourea-mutagenized mice links Gsdmd to the intracellular lipopolysaccharide response. Macrophages from [Gsdmd.sup.-/-] mice generated by gene targeting also exhibit defective pyroptosis and interleukin-1β secretion induced by cytoplasmic lipopolysaccharide or Gram-negative bacteria. In addition, [Gsdmd.sup.-/-] mice are protected from a lethal dose of lipopolysaccharide. Mechanistically, caspase-11 cleaves gasdermin D, and the resulting amino-terminal fragment promotes both pyroptosis and NLRP3-dependent activation of caspase-1 in a cell-intrinsic manner. Our data identify gasdermin D as a critical target of caspase-11 and a key mediatorof the host response against Gram-negative bacteria.

The expanding number of rare immunodeficiency syndromes offers an opportunity to understand key genes that support immune defence against infectious diseases. However, patients with these diseases are by definition rare. In addition, any analysis is complicated by treatments and co-morbid infections requiring the use of mouse models for detailed investigations. Here we develop a mouse model of DOCK2 immunodeficiency and demonstrate that these mice have delayed clearance of herpes simplex virus type 1 (HSV-1) infections. Further, we found that they have a critical, cell intrinsic role of DOCK2 in the clonal expansion of anti-viral CD8 + T cells despite normal early activation of these cells. Finally, while the major deficiency is in clonal expansion, the ability of primed and expanded DOCK2-deficient CD8 + T cells to protect against HSV-1-infection is also compromised. These results provide a contributing cause for the frequent and devastating viral infections seen in DOCK2-deficient patients and improve our understanding of anti-viral CD8 + T cell immunity., Competing Interests: Conflict of interest: The authors declare that they have no conflicts of interest.