Antiviral roles of natural killer (NK) cell subsets were examined in C57BL/6 mice infected with murine cytomegalovirus (MCMV) and other viruses, including lymphocytic choriomeningitis virus (LCMV), vaccinia virus (VV), and mouse hepatitis virus (MHV). Each virus vigorously induced an NK cell infiltrate into the peritoneal cavity and liver, causing some redistributions of NK cell subsets defined by monoclonal antibody (mAb) directed against Ly49A, C/I, D, and G2. Striking results were seen with a mAb (1F8) reactive with the positively signaling molecule Ly49H, present in MCMV-resistant C57BL/6 mice. mAb 1F8 also stains Ly49 C and I, but exclusion of those reactivities with mAb 5E6, which recognizes Ly49 C and I, indicated that Ly49H+ cells infiltrated the peritoneal cavity and liver and were particularly effective at synthesizing interferon γ. Depletion of 1F8+ but not 5E6+ cells in vivo by mAb injections enhanced MCMV titers by 20-1,000-fold in the spleen and approximately fivefold in the liver. Titers of LCMV or VV were not enhanced. These anti-MCMV effects were attributed to prototypical NK1.1+CD3− NK cells and not to NK1.1+CD3+ “NK/T” cells. This is the first evidence that control of a virus infection in vivo is mediated by a distinct NK cell subset.

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Introduction We describe a previously unreported 437 T→G missense mutation producing a V146G substitution in the first coiled-coil (CC1) domain of nuclear factor-κB essential modulator (NEMO) in a 9-month-old boy with ectodermal dysplasia with immunodeficiency who presented with methicillin-resistant Staphylococcus aureus subdural empyema. We performed in vitro experiments to determine if this novel mutation resulted in impaired NF-κB signaling. Methods IκBα phosphorylation experiments were performed using a Jurkat T cell line lacking endogenous NEMO expression that was transfected with vectors containing either the wild type or the patient’s V146G mutation. The cells were stimulated with TNF-α to activate the NF-κB pathway. Phosphorylated IκBα was detected by immunoblotting with anti-phospho-IκBα antibodies. Peripheral blood mononuclear cells from the patient were stimulated with TNF-α or anti-CD3 and anti-CD28. Impaired IκBα degradation was detected using antibodies against the IκBα protein. Results While TNF-α stimulation resulted in IκBα phosphorylation in NEMO-deficient Jurkat cells reconstituted with wild-type NEMO, cell transfected with the V146G mutant exhibited a 75% reduction in phospho-IκBα. Peripheral blood mononuclear cells from the patient showed impaired degradation of IκBα after stimulation when compared with normal controls. Conclusions The patient’s V146G mutation results in impaired NF-κB activation in vitro. The mutation extends the known N-terminal boundary within the CC1 domain that produces an ectodermal dysplasia phenotype, and defines an infectious susceptibility previously unappreciated in ectodermal dysplasia with immunodeficiency (methicillin-resistant S. aureus subdural empyema), broadening the clinical spectrum associated with the disease.

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