Natural killer (NK) cells are lymphocytes that play an important role in the immune response to infection and malignancy. Recent studies in mice have shown that stimulation of NK cells with cytokines ...or in the context of a viral infection results in memory-like properties. We hypothesized that human NK cells exhibit such memory-like properties with an enhanced recall response after cytokine preactivation. In the present study, we show that human NK cells preactivated briefly with cytokine combinations including IL-12, IL-15, and IL-18 followed by a 7- to 21-day rest have enhanced IFN-γ production after restimulation with IL-12 + IL-15, IL-12 + IL-18, or K562 leukemia cells. This memory-like phenotype was retained in proliferating NK cells. In CD56dim NK cells, the memory-like IFN-γ response was correlated with the expression of CD94, NKG2A, NKG2C, and CD69 and a lack of CD57 and KIR. Therefore, human NK cells have functional memory-like properties after cytokine activation, which provides a novel rationale for integrating preactivation with combinations of IL-12, IL-15, and IL-18 into NK cell immunotherapy strategies.
NK cells, lymphocytes of the innate immune system, are important for defense against infectious pathogens and cancer. Classically, the CD56dim NK cell subset is thought to mediate antitumor ...responses, whereas the CD56bright subset is involved in immunomodulation. Here, we challenge this paradigm by demonstrating that brief priming with IL-15 markedly enhanced the antitumor response of CD56bright NK cells. Priming improved multiple CD56bright cell functions: degranulation, cytotoxicity, and cytokine production. Primed CD56bright cells from leukemia patients demonstrated enhanced responses to autologous blasts in vitro, and primed CD56bright cells controlled leukemia cells in vivo in a murine xenograft model. Primed CD56bright cells from multiple myeloma (MM) patients displayed superior responses to autologous myeloma targets, and furthermore, CD56bright NK cells from MM patients primed with the IL-15 receptor agonist ALT-803 in vivo displayed enhanced ex vivo functional responses to MM targets. Effector mechanisms contributing to IL-15-based priming included improved cytotoxic protein expression, target cell conjugation, and LFA-1-, CD2-, and NKG2D-dependent activation of NK cells. Finally, IL-15 robustly stimulated the PI3K/Akt/mTOR and MEK/ERK pathways in CD56bright compared with CD56dim NK cells, and blockade of these pathways attenuated antitumor responses. These findings identify CD56bright NK cells as potent antitumor effectors that warrant further investigation as a cancer immunotherapy.
Ebola virus disease in humans is highly lethal, with case fatality rates ranging from 25 to 90%. There is no licensed treatment or vaccine against the virus, underscoring the need for efficacious ...countermeasures. We ascertained that a human survivor of the 1995 Kikwit Ebola virus disease outbreak maintained circulating antibodies against the Ebola virus surface glycoprotein for more than a decade after infection. From this survivor we isolated monoclonal antibodies (mAbs) that neutralize recent and previous outbreak variants of Ebola virus and mediate antibody-dependent cell-mediated cytotoxicity in vitro. Strikingly, monotherapy with mAb114 protected macaques when given as late as 5 days after challenge. Treatment with a single human mAb suggests that a simplified therapeutic strategy for human Ebola infection may be possible.
The solution self-assembly of macromolecular amphiphiles offers an efficient, bottom-up strategy for producing well-defined nanocarriers, with applications ranging from drug delivery to nanoreactors. ...Typically, the generation of uniform nanocarrier architectures is controlled by processing methods that rely on cosolvent mixtures. These preparation strategies hinge on the assumption that macromolecular solution nanostructures are kinetically stable following transfer from an organic/aqueous cosolvent into aqueous solution. Herein we demonstrate that unequivocal step-change shifts in micelle populations occur over several weeks following transfer into a highly selective solvent. The unexpected micelle growth evolves through a distinct bimodal distribution separated by multiple fusion events and critically depends on solution agitation. Notably, these results underscore fundamental similarities between assembly processes in amphiphilic polymer, small molecule and protein systems. Moreover, the non-equilibrium micelle size increase can have a major impact on the assumed stability of solution assemblies, for which performance is dictated by nanocarrier size and structure.
NK cells are innate lymphoid cells that are critical for host defense against infection, and mediate anti‐tumor responses. MicroRNAs (miRNAs) are a large family of small noncoding RNAs that target ...the 3′ untranslated region (UTR) of mRNAs, thereby attenuating protein translation. The expression of miRNAs within human peripheral blood and mouse splenic NK cells has been cataloged, with the majority of the miRNA sequence pool represented in the top 60 most abundantly expressed miRNAs. Global miRNA deficiency within NK cells has confirmed their critical role in NK‐cell biology, including defects in NK‐cell development and altered functionality. Studies using gain‐ and loss‐of‐function of individual miRNAs in NK cells have demonstrated the role of specific miRNAs in regulating NK‐cell development, maturation, and activation. miRNAs also regulate fundamental NK‐cell processes including cytokine production, cytotoxicity, and proliferation. This review provides an update on the intrinsic miRNA regulation of NK cells, including miRNA expression profiles, as well as their impact on NK‐cell biology. Additional profiling is needed to better understand miRNA expression within NK‐cell developmental intermediates, subsets, tissues, and in the setting of disease. Furthermore, key open questions in the field as well as technical challenges in the study of miRNAs in NK cells are highlighted.
The Article analyzes claims of police misconduct and false arrest, specifically addressing the issue of whether a police officer may ignore evidence of an affirmative defense, such as self-defense, ...when determining probable cause for an arrest. The inquiry most often arises in § 1983 civil claims for false arrest where the officer was aware of evidence a crime had been committed, but was also aware of facts indicating the suspect had an affirmative defense to the crime observed. In extreme cases, the affirmative defense at issue is actually self-defense in response to the officer's own unlawful conduct. As police brutality and false arrest claims rise, so too will the prevalence of this issue. The Article examines rulings from all jurisdictions having addressed the topic and highlights the matter of Thomas v. City of Galveston involving a citizen who was arrested when attempting to stop two police officers from stealing his generator in the aftermath of a hurricane. In a subsequent civil suit for false arrest, the officers defended the claim by asserting they had probable cause for the arrest, despite knowing Mr. Thomas was merely defending his property from their own mischievous conduct. Finding for Mr. Thomas, the court concluded that under certain circumstances, a police officer's awareness of the facts supporting an affirmative defense can negate probable cause. This view, however, is not universal-several other courts have reached the opposite conclusion: that an affirmative defense bears no relevance in probable cause analysis. An examination of rulings nationally reveals common themes on this issue as courts struggle to reconcile the incorporation of an affirmative defense with existing principles governing probable cause analysis. Consideration of an available affirmative defense when analyzing probable cause helps to ensure accountability of police officers who unlawfully arrest a citizen they know, or reasonably should know, committed no crime. Scenarios such as those in Thomas v. City of Galveston are not as unique as one might assume. The Article provides numerous examples from across the country of courts grappling with this issue. The Article brings some analytical coherence to the complicated legal and factual situations that may lead courts to abandon certain traditional rules governing probable cause in favor of more leniency for plaintiffs seeking a remedy for police misconduct. The Article concludes with a recommendation that courts adopt and apply a general rule that facts supporting an affirmative defense shall be considered among the totality of facts and circumstances available to the arresting officer, and that such exculpatory facts shall be evaluated with the same level of scrutiny afforded inculpatory facts.
Natural killer (NK) cells are cytotoxic type 1 innate lymphoid cells (ILCs) that defend against viruses and mediate anti-tumor responses, yet mechanisms controlling their development and function ...remain incompletely understood. We hypothesized that the abundantly expressed microRNA-142 (miR-142) is a critical regulator of type 1 ILC biology. Interleukin-15 (IL-15) signaling induced miR-142 expression, whereas global and ILC-specific miR-142-deficient mice exhibited a cell-intrinsic loss of NK cells. Death of NK cells resulted from diminished IL-15 receptor signaling within miR-142-deficient mice, likely via reduced suppressor of cytokine signaling-1 (Socs1) regulation by miR-142-5p. ILCs persisting in Mir142−/− mice demonstrated increased expression of the miR-142-3p target αV integrin, which supported their survival. Global miR-142-deficient mice exhibited an expansion of ILC1-like cells concurrent with increased transforming growth factor-β (TGF-β) signaling. Further, miR-142-deficient mice had reduced NK-cell-dependent function and increased susceptibility to murine cytomegalovirus (MCMV) infection. Thus, miR-142 critically integrates environmental cues for proper type 1 ILC homeostasis and defense against viral infection.
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•miR-142 is induced by IL-15 and is required for type 1 ILC development and homeostasis•miR-142 targets Socs1 thereby promotes IL-15 receptor signaling in type 1 ILCs•αV integrin, a miR142-3p target, promotes IL-15-independent survival in type 1 ILCs•miR-142 is critical for cytokine production and NK-cell-mediated viral control
IL-15 and TGF-β support the homeostasis and molecular programs of distinct innate lymphoid cell (ILC) types. Berrien-Elliott and colleagues identify that microRNA-142 is required for IL-15 receptor signaling and NK cell survival, whereas loss of microRNA-142 results in distinct TGF-β- and/or integrin-supported type 1 ILCs.
Natural killer (NK) cells are cytotoxic innate lymphoid cells (ILCs) that mediate antiviral and antitumor responses and require the transcriptional regulator Eomesodermin (Eomes) for early ...development. However, the role of Eomes and its molecular program in mature NK cell biology is unclear. To address this, we develop a tamoxifen-inducible, type-1-ILC-specific (Ncr1-targeted) cre mouse and combine this with Eomes-floxed mice. Eomes deletion after normal NK cell ontogeny results in a rapid loss of NK cells (but not ILC1s), with a particularly profound effect on penultimately mature stage III NK cells. Mechanisms responsible for stage III reduction include increased apoptosis and impaired maturation from stage II precursors. Induced Eomes deletion also decreases NK cell cytotoxicity and abrogates in vivo rejection of major histocompatibility complex (MHC)-class-I-deficient cells. However, other NK cell functional responses, and stage IV NK cells, are largely preserved. These data indicate that mature NK cells have distinct Eomes-dependent and -independent stages.
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•Induced Eomes deletion results in a rapid decrease in NK cell numbers•Eomes-deleted stage III NK cells exhibit increased apoptosis•Eomes-deleted stage II and III NK cells exhibit differentiation defects•Induced Eomes deletion compromises NK cytotoxicity and MHCI−/− rejection in vivo
The transcription factor Eomes is important for early natural killer (NK) cell development. Wagner et al. utilize an inducible, type 1 ILC-specific cre model to demonstrate a stage-specific role for Eomes in NK cell survival and homeostasis as well as a persistent requirement for Eomes in promoting NK cell cytotoxicity.
Leucine-rich repeat and immunoglobulin domain-containing protein (Lingo-1) plays a vital role in a large number of neuronal processes underlying learning and memory, which are known to be disrupted ...in schizophrenia. However, Lingo-1 has never been examined in the context of schizophrenia. The genetic association of a single-nucleotide polymorphism (SNP, rs3144) and methylation (CpG sites) in the Lingo-1 3′-UTR region was examined, with the testing of cognitive dysfunction and white matter (WM) integrity in a schizophrenia case-control cohort (n = 268/group). A large subset of subjects (97 control and 161 schizophrenia subjects) underwent structural magnetic resonance imaging (MRI) brain scans to assess WM integrity. Frequency of the rs3144 minor allele was overrepresented in the schizophrenia population (p = 0.03), with an odds ratio of 1.39 (95% CI 1.016–1.901). CpG sites surrounding rs3144 were hypermethylated in the control population (p = 0.032) compared to the schizophrenia group. rs3144 genotype was predictive of membership to a subclass of schizophrenia subjects with generalized cognitive deficits (p < 0.05), in addition to having associations with WM integrity (p = 0.018). This is the first study reporting a potential implication of genetic and epigenetic risk factors in Lingo-1 in schizophrenia. Both of these genetic and epigenetic alterations may also have associations with cognitive dysfunction and WM integrity in the context of the schizophrenia pathophysiology.
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