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Human CMV (HCMV) is a ubiquitous pathogen that indelibly shapes the NK cell repertoire. Using transcriptomic, epigenomic, and proteomic approaches to evaluate peripheral blood NK cells from healthy human volunteers, we find that prior HCMV infection promotes NK cells with a T cell–like gene profile, including the canonical markers CD3ε, CD5, and CD8β, as well as the T cell lineage–commitment transcription factor Bcl11b. Although Bcl11b expression is upregulated during NK maturation from CD56bright to CD56dim, we find a Bcl11b-mediated signature at the protein level for FcεRIγ, PLZF, IL-2Rβ, CD3γ, CD3δ, and CD3ε in later-stage, HCMV-induced NK cells. BCL11B is targeted by Notch signaling in T cell development, and culture of NK cells with Notch ligand increases cytoplasmic CD3ε expression. The Bcl11b-mediated gain of CD3ε, physically associated with CD16 signaling molecules Lck and CD247 in NK cells is correlated with increased Ab-dependent effector function, including against HCMV-infected cells, identifying a potential mechanism for their prevalence in HCMV-infected individuals and their prospective clinical use in Ab-based therapies.

Cytokine signaling via signal transducer and activator of transcription (STAT) proteins is crucial for optimal antiviral responses of natural killer (NK) cells. However, the pleiotropic effects of both cytokine and STAT signaling preclude the ability to precisely attribute molecular changes to specific cytokine–STAT modules. Here, we employed a multi-omics approach to deconstruct and rebuild the complex interaction of multiple cytokine signaling pathways in NK cells. Proinflammatory cytokines and homeostatic cytokines formed a cooperative axis to commonly regulate global gene expression and to further repress expression induced by type I interferon signaling. These cytokines mediated distinct modes of epigenetic regulation via STAT proteins, and collective signaling best recapitulated global antiviral responses. The most dynamically responsive genes were conserved across humans and mice, which included a cytokine–STAT-induced cross-regulatory program. Thus, an intricate crosstalk exists between cytokine signaling pathways, which governs NK cell responses. Sun and colleagues provide a new resource, multi-omics analysis of NK cell Jak–STAT signaling in response to the cytokines IL-2, IL-15, IL-12, IL-18 and IFN-α, showing synergistic and antagonistic interactions that govern NK cell activity.

CD8(+) T cells are critical mediators of adaptive immunity but may also exhibit innate-like properties such as surface expression of NKG2C, an activating receptor typically associated with natural killer (NK) cells. We demonstrate that, similar to NK cells, NKG2C(+)TCRαβ(+)CD8(+) T cells are associated with prior human cytomegalovirus (HCMV) exposure. In addition to expressing several NK cell markers such as CD56 and KIR, NKG2C(+)CD8(+) T cells are oligoclonal and do not upregulate PD-1 even in response to persistent activation. Furthermore, we found that NKG2C(+)CD8(+) T cells from some individuals exhibited strong effector function against leukemia cells and HCMV-infected fibroblasts, which was dictated by both NKG2C and TCR specificity. Transcriptomic analysis revealed that the transcription factor BCL11B, a regulator of T cell developmental fate, is significantly downregulated in NKG2C(+)CD8(+) T cells when compared to conventional NKG2C(−)CD8(+) T cells. BCL11B deletion in conventional CD8(+) T cells resulted in the emergence of a similar innate-like CD56(+)CD94(+)DAP12(+)NKG2C(+)CD45RA(+)CCR7(−)PD-1(−/low) T cell population with activity against HLA-E(+) targets. Based on their intrinsic capacity to recognize diseased cells coupled with lack of PD-1 induction, NKG2C(+)CD8(+) T cells represent a lymphocyte population that resides at the boundary between innate and adaptive immunity, presenting an attractive alternative for cellular therapy, including CAR T-based therapies.

CD8+ T cells not only are critical mediators of adaptive immunity but also may exhibit innate-like properties such as surface expression of NKG2C, an activating receptor typically associated with n...

Donor KIR and recipient HLA combinations that minimize inhibition and favor activation of the NK repertoire are associated with improved outcomes after allogeneic hematopoietic cell transplantation (HCT) in patients with myeloid neoplasia. We prospectively evaluated a weighted donor ranking algorithm designed to prioritize HLA-compatible unrelated donors (URDs) with weak inhibitory KIR3DL1/HLA-Bw4 interaction, followed by donors with nontolerized activating KIR2DS1, and finally those with KIR centromeric B haplotype. During donor evaluation, we performed KIR genotyping and ranked 2079 URDs for 527 subjects with myelodysplastic syndrome (MDS) or acute myelogenous leukemia (AML). Among all patients, 394 (75%) had at least 1 KIR-advantageous donor, and 263 (50%) underwent HCT. In patients with AML, KIR3DL1 weak inhibition provided protection from relapse. Compared with KIR3DL1-Weak Inhibiting donors, KIR3DL1-Noninteracting donors were associated with increased risk of relapse (HR, 2.97; 95% CI, 1.33-6.64; P = .008) and inferior event-free survival (EFS; HR, 2.14; 95% CI, 1.16-3.95; P = .015). KIR3DL1-Strong Inhibiting donors were associated with HR, 1.65 (95% CI, 0.66-4.08; P = .25) for AML relapse and HR, 1.6 (95% CI, 0.81-3.17; P = .1) for EFS when compared with the use of KIR3DL1-weak inhibiting donors. Donor KIR2DS1/HLA-C1 status and centromeric KIR haplotype-B content were not associated with decreased risk of AML relapse. There was no benefit to KIR-based donor selection in patients with MDS. This study demonstrates that donor KIR typing is feasible, and prioritization of donors with certain KIR3DL1 genotypes may confer a protection from relapse after HCT in patients with AML.

Human CMV (HCMV) is a ubiquitous pathogen that indelibly shapes the NK cell repertoire. Using transcriptomic, epigenomic, and proteomic approaches to evaluate peripheral blood NK cells from healthy human volunteers, we find that prior HCMV infection promotes NK cells with a T cell–like gene profile, including the canonical markers CD3ε, CD5, and CD8β, as well as the T cell lineage–commitment transcription factor Bcl11b. Although Bcl11b expression is upregulated during NK maturation from CD56(bright) to CD56(dim), we find a Bcl11b-mediated signature at the protein level for FcεRIγ, PLZF, IL-2Rβ, CD3γ, CD3δ, and CD3ε in later-stage, HCMV-induced NK cells. BCL11B is targeted by Notch signaling in T cell development, and culture of NK cells with Notch ligand increases cytoplasmic CD3ε expression. The Bcl11b-mediated gain of CD3ε, physically associated with CD16 signaling molecules Lck and CD247 in NK cells is correlated with increased Ab-dependent effector function, including against HCMV-infected cells, identifying a potential mechanism for their prevalence in HCMV-infected individuals and their prospective clinical use in Ab-based therapies.

HLA-B allotypes exhibiting the Bw4 epitope trigger variable inhibitory signaling of KIR3DL1 receptor types, where strong inhibitory HLA-B and KIR3DL1 allele combinations are associated with increased risk for relapse of acute myelogenous leukemia (AML) following allogeneic hematopoietic cell transplantation (HCT). Several HLA-A allotypes also exhibit the Bw4 epitope. Studies with natural killer (NK) cell clones have demonstrated NK inhibition via KIR3DL1 by HLA-A Bw4+ allotypes, but did not delineate strengths of inhibition or hierarchies of NK education. Using primary NK cells from healthy donors, we demonstrate that HLA-A*23, HLA-A*24, and HLA-A*32 proteins are expressed at different densities and exhibit different capacities to educate and inhibit KIR3DL1-expressing NK cells in vitro. Among the HLA-A Bw4+ allotypes, HLA-A*24 and HLA-A*32 demonstrate the strongest inhibitory capacity. To determine if HLA-A allotypes with strong inhibitory capacity have similar negative impact in allogeneic HCT as HLA-B Bw4+ allotypes, we performed a retrospective analysis of 1729 patients with AML who received an allogeneic HCT from a 9/10 or 10/10 HLA allele-matched unrelated donor. Examination of the donor-recipient pairs whose Bw4 epitope was exclusively contributed from HLA-A*24 and A*32 allotypes revealed that patients with HLA-A*24 who received an allograft from a KIR3DL1+ donor experienced a higher risk of disease relapse (hazard ratio, 1.65; 95% confidence interval, 1.17-2.32; P = .004) when compared with patients without a Bw4 epitope. These findings indicate that despite weak affinity interactions with KIR3DL1, common HLA-A allotypes with the Bw4 epitope can interact with KIR3DL1+ donor NK cells with clinically meaningful impact and provide additional insight to donor NK alloreactivity in HLA-matched HCT.

Allelic diversity of the KIR2DL receptors drive differential expression and ligand-binding affinities that impact natural killer cell function and patient outcomes for diverse cancers. We have developed a global intermediate resolution amplification-refractory mutation system (ARMS) PCR-SSP method for distinguishing functionally relevant subgroups of the KIR2DL receptors, as defined by phylogenetic study of the protein sequences. Use of the ARMS design makes the method reliable and usable as a kit, with all reactions utilizing the same conditions. Six reactions define six subgroups of KIR2DL1; four reactions define three subgroups of KIR2DL2; and five reactions define four subgroups of KIR2DL3. Using KIR allele data from a cohort of 426 European-Americans, we identified the most common KIR2DL subtypes and developed the high-throughput PCR-based methodology, which was validated on a separate cohort of 260 healthy donors. Linkage disequilibrium analysis between the different KIR2DL alleles revealed that seven allelic combinations represent more than 95% of the observed population genotypes for KIR2DL1/L2/L3. In summary, our findings enable rapid typing of the most common KIR2DL receptor subtypes, allowing more accurate prediction of co-inheritance and providing a useful tool for the discrimination of observed differences in surface expression and effector function among NK cells exhibiting disparate KIR2DL allotypes.

Purpose Disease relapse remains a major challenge to successful outcomes in patients who undergo allogeneic hematopoietic cell transplantation (HCT). Donor natural killer (NK) cell alloreactivity in HCT can control leukemic relapse, but capturing alloreactivity in HLA-matched HCT has been elusive. HLA expression on leukemia cells—upregulated in the post-HCT environment—signals for NK cell inhibition via inhibitory killer immunoglobulin-like (KIR) receptors and interrupts their antitumor activity. We hypothesized that varied strengths of inhibition among subtypes of the ubiquitous KIR3DL1 and its cognate ligand, HLA-B, would titrate NK reactivity against acute myelogenous leukemia (AML). Patients and Methods By using an algorithm that was based on polymorphism-driven expression levels and specificities, we predicted and tested inhibitory and cytotoxic NK potential on the basis of KIR3DL1/HLA-B subtype combinations in vitro and evaluated their impact in 1,328 patients with AML who underwent HCT from 9/10 or 10/10 HLA-matched unrelated donors. Results Segregated by KIR3DL1 subtype, NK cells demonstrated reproducible patterns of strong, weak, or noninhibition by target cells with defined HLA-B subtypes, which translated into discrete cytotoxic hierarchies against AML. In patients, KIR3DL1 and HLA-B subtype combinations that were predictive of weak inhibition or noninhibition were associated with significantly lower relapse (hazard ratio [HR], 0.72; P = .004) and overall mortality (HR, 0.84; P = .030) compared with strong inhibition combinations. The greatest effects were evident in the high-risk group of patients with all KIR ligands (relapse: HR, 0.54; P < .001; and mortality: HR, 0.74; P < .008). Beneficial effects of weak and noninhibiting KIR3DL1 and HLA-B subtype combinations were separate from and additive to the benefit of donor activating KIR2DS1. Conclusion Consideration of KIR3DL1-mediated inhibition in donor selection for HLA-matched HCT may achieve superior graft versus leukemia effects, lower risk for relapse, and an increase in survival among patients with AML.

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We conducted a phase 2 study to determine the efficacy of HLA-haploidentical related donor natural killer (NK) cells after cyclophosphamide-based lymphodepletion in patients with relapsed or progressive acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) following allogeneic hematopoietic cell transplantation (HCT). Eight patients (2 with MDS and 6 with AML) were treated with cyclophosphamide 50 mg/kg on day -3 and day -2 before infusion of NK cells isolated from a haploidentical related donor. One patient also received fludarabine 25 mg/m2/day for 4 days. Six doses of 1 million units of interleukin-2 (IL-2) were administered on alternating days beginning on day -1. The median number of NK cells infused was 10.6 × 10(6)/kg (range, 4.3 to 22.4 × 10(6)/kg), and the median number of CD3 cells infused was 2.1 × 10(3)/kg (range, 1.9 to 40 × 10(3)/kg). NK infusions were well tolerated, with a median time to neutrophil recovery of 19 days (range, 7 days to not achieved) and no incidence of graft-versus-host disease after NK infusion. One patient with AML and 1 patient with MDS achieved a complete response, but relapsed at 1.7 and 1.8 months, respectively. One patient with MDS experienced resolution of dysplastic features but persistence of clonal karyotype abnormalities; this patient was stable at 65 months after NK cell therapy. The median duration of survival was 12.9 months (range, 0.8 to 65.3 months). Chimerism analysis of CD3(-)/CD56(+) peripheral blood cells did not detect any circulating haploidentical NK cells after infusion. NK phenotyping was performed in 7 patients during and after IL-2 infusion. We found a slight trend toward greater expression of KIR2DL2/2DL3/2DS2 (5% versus 28%; P = .03) at 14 days in patients who survived longer than 6 months from NK cell infusion (n = 4) compared with those who died within 6 months of NK cell therapy (n = 3). In summary, our data support the safety of haploidentical NK cell infusion after allogeneic HCT.

Retrospective studies indicate that the use of unrelated hematopoietic stem cell donors with Killer Ig-like Receptor (KIR) genotypes resulting in low inhibitory interactions with recipient HLA are associated with lower relapse and higher survival in patients with myeloid neoplasia undergoing allogeneic hematopoietic cell transplantation (allo HCT). To validate these findings in a prospective fashion and to determine if advantageous KIR donors can readily be identified for patients with myeloid neoplasia, we prospectively KIR genotyped and provided KIR/HLA-based ranking for unrelated donors (URD) evaluated for patients with a diagnosis of acute myeloid leukemia or myelodysplastic syndrome undergoing workup at our center for allo HCT. Donors were prioritized first to minimize inhibitory KIR3DL1 - HLA-Bw4 interactions, followed by prioritization of donors with non-tolerized activating KIR2DS1, and finally prioritizing donors homozygous for the centromeric B haplotype. We evaluated 2,079 donors for 527 patients (median 4 donors per patient), among whom 263 ultimately underwent allo HCT. In a multivariate analysis adjusting for age, HCT-CI, and conditioning intensity, we found that the use of a KIR3DL1-low-inhibition donor was associated with an improved hazard for survival (HR = 0.58 (95% confidence interval (CI): 0.35 – 0.96), P = 0.035) and event-free survival (HR = 0.61 (95% CI: 0.39 – 0.93), P = 0.023) due to a decreased hazard for relapse (HR = 0.52, 95% CI: 0.30 – 0.90, P = 0.021) without increased non-relapse mortality when compared to KIR3DL1-non-interacting or -high-inhibition donors. Donor KIR2DS1/HLA-C1 status and centromeric haplotype B content were not predictive of relapse or survival in this cohort. Among 339 HLA-Bw4+ patients evaluated for transplant, 242 (71.4%) had an available KIR3DL1-low-inhibition donor and 205 (60.5%) had a mixture of KIR3DL1-low-inhibition with either -high-inhibition or -non-interacting donors facilitating a choice using donor KIR3DL1 genotyping. Evaluating greater numbers of donors associated with an increased probability of identifying an advantageous donor based on inhibitory KIR3DL1 interactions (P

International audience; Intradermal (ID) vaccination constitutes a promising approach to induce anti-infectious immunity. This route of immunization has mostly been studied with influenza split-virion vaccines. However, the efficacy of ID vaccination for sub-unit vaccines in relation to underlying skin innate immunity remains to be explored for wider application in humans. Relevant animal models that more closely mimic human skin immunity than the widely used mouse models are therefore necessary. Here, we show in domestic swine, which shares striking anatomic and functional properties with human skin, that a single ID delivery of pseudorabies virus (PRV) glycoproteins without added adjuvant is sufficient to trigger adaptive cellular and humoral immune responses, and to confer protection from a lethal respiratory infection with PRV. Analysis of early events at the skin injection site revealed up-regulation of pro-inflammatory cytokine and chemokine genes, recruitment of neutrophils and monocytes and accumulation of inflammatory DC. We further show that the sustained induction of pro-inflammatory cytokine genes results from the combined effects of skin puncture, liquid injection in the dermis and viral antigens. These data highlight that immune protection against respiratory infection can be induced by ID vaccination with a subunit vaccine and reveal that adjuvant requirements are circumvented by the mechanical and antigenic stress caused by ID injection, which triggers innate immunity and mobilization of inflammatory DC at the immunization site. ID vaccination with sub-unit vaccines may thus represent a safe and efficient solution for protection against respiratory infections in swine and possibly also in humans, given the similarity of skin structure and function in both species.

Summary The process of affinity maturation, whereby T and B cells bearing antigen receptors with optimal affinity to the relevant antigen undergo preferential expansion, is a key feature of adaptive immunity. Natural killer (NK) cells are innate lymphocytes capable of “adaptive” responses after cytomegalovirus (CMV) infection. However, whether NK cells are similarly selected on the basis of their avidity for cognate ligand is unknown. Here, we showed that NK cells with the highest avidity for the mouse CMV glycoprotein m157 were preferentially selected to expand and comprise the memory NK cell pool, whereas low-avidity NK cells possessed greater capacity for interferon-γ (IFN-γ) production. Moreover, we provide evidence for avidity selection occurring in human NK cells during human CMV infection. These results delineate how heterogeneity in NK cell avidity diversifies NK cell effector function during antiviral immunity, and how avidity selection might serve to produce the most potent memory NK cells.

Adaptive lymphocyte clones with the greatest receptor affinity tend to dominate primary and secondary immune responses. Strength of receptor signal and receptor abundance, along with competition for antigen and cytokines, drive preferential outgrowth of certain clones, shaping the effector and memory pool in selection processes known as affinity and avidity maturation. Natural killer (NK) cells are innate lymphocytes capable of “adaptive” responses following infectious challenges. However, whether NK cells undergo a similar selection process on the basis of their avidity for cognate ligand is not known. Here, we show that NK cells with a broad range of avidities for the mouse cytomegalovirus (MCMV) glycoprotein m157 are initially recruited after virus infection, but those with highest avidity are selected to undergo the greatest clonal expansion to comprise the memory NK cell population. Furthermore, pre-established levels of Ly49H receptor expression within the Ly49H+ NK cell pool dictated the functional contribution of a given NK cell during MCMV infection, with lower avidity NK cells possessing greater capacity for IFN-γ production, and higher avidity NK cells possessing greater capacity for cytotoxicity and adaptive responses. Moreover, we provide evidence for avidity selection also occurring in human NK cells during human CMV (HCMV) infection. These results provide a mechanistic understanding of how heterogeneity in NK cell avidity underlies the diversification of NK cell effector function during a primary antiviral immune response, and how the process of avidity selection may serve to produce the most potent memory NK cell pool.

Background Induction of oral tolerance to haptens is an efficient way to prevent allergic contact dermatitis (ACD) in mice. Toll-like receptor (TLR)–mediated sensing of the microbiota contributes to gut homeostasis, yet whether it contributes to induction of oral tolerance has not been documented. Objective We examined whether oral tolerance to the contact sensitizer 2,4-dinitro-fluorobenzene (DNFB) depends on microbiota/TLRs and evaluated the role of TLR4 on the tolerogenic function of intestinal dendritic cells (DCs). Methods Oral tolerance was induced by DNFB gavage in germ-free and mice deficient in several TLRs. Tolerance was assessed by means of suppression of contact hypersensitivity and hapten-specific IFN-γ–producing effector T cells. The tolerogenic function of intestinal DCs was tested by adoptive transfer experiments, ex vivo hapten presentation, and forkhead box p3 regulatory T-cell conversion. Results Oral tolerance induced by DNFB gavage was impaired in germ-free mice and TLR4-deficient mice. Bone marrow chimeras revealed that TLR4 expression on hematopoietic cells was necessary for oral tolerance induction. TLR4 appeared to be essential for the ability of intestinal dendritic cells from DNFB-fed mice to inhibit ACD on adoptive transfer. Indeed, TLR4 conditioned the in vivo mobilization to mesenteric lymph nodes of intestinal migratory CD103 + DCs carrying oral DNFB, especially the CD103 + CD11b + DC subset expressing the vitamin A–converting enzyme retinaldehyde dehydrogenase and specialized in forkhead box p3–positive regulatory T-cell conversion. Conclusions Our data demonstrate that TLR4 conditions induction of oral tolerance to DNFB through licensing tolerogenic gut DCs. Oral biotherapy with TLR4 ligands might be useful to potentiate oral tolerance to haptens and alleviate ACD in human subjects.

Purpose In patients with neuroblastoma (NB), treatment with anti-GD2 monoclonal antibody (mAb) directs natural killer (NK) cell–mediated antibody-dependent cellular cytotoxicity (ADCC) against tumor cells. However, tumor cytotoxicity is attenuated by ligation of inhibitory killer immunoglobulin-like receptors (KIRs) by HLA class I molecules. KIR3DL1 polymorphism influences its ability to engage HLA-Bw4 ligands. We tested the hypothesis that poorly interacting combinations of KIR3DL1 and HLA ligands are more permissive of mAb-mediated antitumor effect. Methods KIR3DL1 and HLA-B subtyping were performed with a multiplex intermediate-resolution polymerase chain reaction assay for a cohort of 245 patients who were treated with antibody 3F8 for high-risk NB. Patient outcomes were analyzed according to expected degree of interaction between KIR3DL1 and HLA-B subtypes and grouped as strong, weak, or noninteractors. A comparison of NK response to 3F8 mAb opsonized NB cells between strong- and noninteracting donors was performed by flow cytometry. Results KIR3DL1 and HLA-B subtype combinations associated with noninteraction as a result of lack of receptor expression [KIR3DL1(−)], failure of interaction with inhibitory ligands [KIR3DS1(+)], or absence of KIR ligands resulted in significantly improved overall and progression-free survival. Patients with KIR3DL1 and HLA-B subtype combinations that were predictive of weak interaction had superior outcomes compared with those that were predictive of strong interaction; however, both groups were inferior to those with noninteracting subtype combinations. In vitro analysis of 3F8-mediated ADCC showed that KIR3DL1(−) and 3DS1(+) NK cells were insensitive to inhibition by HLA-Bw4–expressing NB targets. Conclusion We conclude that KIR3LD1 and HLA-B allele combinations can have a prognostic impact on patient survival after treatment with anti-GD2 mAb that relies on NK-ADCC. The survival advantage seen in noninteracting combinations supports the therapeutic disinhibition of individuals with strongly interacting KIR and ligand pairs.

Survival outcomes for patients with high-risk neuroblastoma (NB) have significantly improved with anti-disialoganglioside GD2 mAb therapy, which promotes NK cell activation through antibody-dependent cell-mediated cytotoxicity. NK cell activation requires an interaction between inhibitory killer cell immunoglobulin-like receptors (KIRs) and HLA class I ligands. NK cells lacking KIRs that are specific for self HLA are therefore “unlicensed” and hyporesponsive. mAb-treated NB patients lacking HLA class I ligands for their inhibitory KIRs have significantly higher survival rates, suggesting that NK cells expressing KIRs for non-self HLA are mediating tumor control in these individuals. We found that, in the presence of mAb, both licensed and unlicensed NK cells are highly activated in vitro. However, HLA class I expression on NB cell lines selectively inhibited licensed NK cell activity, permitting primarily unlicensed NK cells to mediate antibody-dependent cell-mediated cytotoxicity. These results indicate that unlicensed NK cells play a key antitumor role in patients undergoing mAb therapy via antibody-dependent cell-mediated cytotoxicity, thus explaining the potent “missing KIR ligand” benefit in patients with NB.

Natural killer (NK) cell-mediated antibody-dependent toxicity is a potent mechanism of action of the anti-GD2 murine monoclonal antibody 3F8 (m3F8). Killer immunoglobulin-like receptor (KIR) and HLA genotypes modulate NK activity and are key prognostic markers in m3F8-treated patients with neuroblastoma. Endogenous NK-cells are suppressed in the setting of high tumor burden and chemotherapy. Allogeneic NK-cells however, demonstrate potent anti-neuroblastoma activity. We report on the results of a phase I clinical trial of haploidentical NK-cells plus m3F8 administered to patients with high-risk neuroblastoma after conditioning chemotherapy. The primary objective was to determine the maximum tolerated NK-cell dose (MTD). Secondary objectives included assessing anti-neuroblastoma activity and its relationship to donor-recipient KIR/HLA genotypes, NK function, and donor NK chimerism. Patients received a lymphodepleting regimen prior to infusion of haploidentical CD3-CD56+ NK-cells, followed by m3F8. Overall and progression free survival (PFS) were assessed from the time of first NK-cell dose. Univariate Cox regression assessed relationship between dose and outcomes. Thirty-five patients received NK-cells at one of five dose levels ranging from 10×10(6) CD56+cells/kg had improved PFS (HR: 0.36, 95%CI: 0.15–0.87, p = 0.022). Patient NK-cells displayed high NKG2A expression, leading to inhibition by HLA-E-expressing neuroblastoma cells. Adoptive NK-cell therapy in combination with m3F8 is safe and has anti-neuroblastoma activity at higher cell doses.

The study's results suggest that Slfn3 could have a role in T cell differentiation and activation. Members of the Slfn protein family have been implicated in the regulation of cell growth, hematopoietic cell differentiation, and T cell development/differentiation in the thymus. Ten members of this family have been described in the mouse, and they have been divided into three subgroups based on the overall sequence homology and the size of the encoded proteins. We have identified Slfn3, a member of Subgroup II, as an overexpressed gene in CD4+ CD25+ T cells in the periphery. Interestingly, we demonstrate that upon activation and proliferation, Slfn3 mRNA is down-regulated in CD4+ CD25+ Tregs and up-regulated in CD4+ CD25– Teffs. Moreover, TGF-β inhibits the expression of Slfn3 in anti-CD3/CD28-activated CD4+ T cells, and the same conditions induce FoxP3 mRNA. Our results suggest that Slfn3 could have a role in T cell differentiation and activation.

NK cells recognize self-HLA via killer Ig-like receptors (KIR). Homeostatic HLA expression signals for inhibition via KIR, and downregulation of HLA, a common consequence of viral infection, allows NK activation. Like HLA, KIR are highly polymorphic, and allele combinations of the most diverse receptor–ligand pair, KIR3DL1 and HLA-B, correspond to hierarchical HIV control. We used primary cells from healthy human donors to demonstrate how subtype combinations of KIR3DL1 and HLA-B calibrate NK education and their consequent capacity to eliminate HIV-infected cells. High-density KIR3DL1 and Bw4-80I partnerships endow NK cells with the greatest reactivity against HLA-negative targets; NK cells exhibiting the remaining KIR3DL1/HLA-Bw4 combinations demonstrate intermediate responsiveness; and Bw4-negative KIR3DL1+ NK cells are poorly responsive. Cytotoxicity against HIV-infected autologous CD4+ T cells strikingly correlated with reactivity to HLA-negative targets. These findings suggest that the programming of NK effector function results from defined features of receptor and ligand subtypes. KIR3DL1 and HLA-B subtypes exhibit an array of binding strengths. Like KIR3DL1, subtypes of HLA-Bw4 are expressed at distinct, predictable membrane densities. Combinatorial permutations of common receptor and ligand subtypes reveal binding strength, receptor density, and ligand density to be functionally important. These findings have immediate implications for prognosis in patients with HIV infection. Furthermore, they demonstrate how features of KIR and HLA modified by allelic variation calibrate NK cell reactive potential.

Background. We have previously demonstrated that a short-course treatment with LF15-0195, a 15-deoxyspergualin analogue, induces donor-specific tolerance of cardiac allografts in rats and expansion of splenic CD4 + CD25 + regulatory T cells. Methods. To further characterize long-term tolerance in this model, we have analyzed the phenotype, regulatory properties and TCR-V/3 usage of the T cells infiltrating the tolerated allografts. Results. We demonstrate that the tolerated allografts express high levels of FoxP3 transcripts and contain a large number of CD4 + T cells, half of which express CD25. Moreover, T cells from these tolerated allografts are very powerful at transferring tolerance to a subsequent allograft recipient, demonstrating the presence of potent regulatory T cells at the site of the graft. Interestingly, the T cells infiltrating the tolerated allografts systematically display restricted V/37 TCR rearrangements. Conclusion. These results demonstrate in this model of tolerance, a specific accumulation of T cells with potent regulatory properties and exhibiting restricted Vβ7-TCR rearrangements at the graft site.

Background. Porcine skin is increasingly being employed as a model of human skin in various research fields, including pharmacology, toxicology and immunology, with particular interest in percutaneous permeation and organ transplantation. Porcine skin shows several anatomical and physiological similarities, but also some differences, with human skin, but few in depth comparative studies are so far available. Ojectives. To study the immunohistochemical properties of normal porcine skin in comparison with human skin. Materials and methods. We performed a histological and immunohistochemical study on frozen and formalin-fixed, paraffin-embedded skin biopsies from domestic swine and normal human skin, using a panel of 93 monoclonal or polyclonal antibodies recognizing various human and porcine skin cell types or structures. Results. We found that several antibodies used to detect normal human skin cells showed equivalent immunoreactivity on normal porcine skin. However, some antibodies commonly used to detect human skin antigens remained unreactive on porcine skin. Conclusions. Our findings highlight the main immunohistochemical properties of porcine skin in comparison with those of human skin and provide a morphological and immunohistochemical basis useful to researchers using porcine skin.

Donor natural killer (NK) cells impart a potent anti-leukemia effect after allogeneic hematopoietic cell transplantation (allo HCT). The killer Ig-like receptors (KIR) play a central role in modulating NK effector function. Chief among them, the inhibitory KIR3DL1 exhibits a high degree of allelic polymorphism. We previously demonstrated that highly expressed KIR3DL1 alleles (KIR3DL1 allele groups *001 and *002) bind preferentially to HLA-Bw4 with I80 to confer a high degree of inhibitory signaling. Similarly, poorly expressed KIR3DL1 alleles (KIR3DL1 allele groups *005 and *007) bind to HLA-Bw4 with T80 to confer a strong inhibitory signal. In a retrospective cohort of 299 patients undergoing allo HCT for AML, we demonstrated that these highly inhibitory donor KIR3DL1/recipient HLA-Bw combinations (KIR3DL1-HIGH) resulted in a greater incidence of recipient relapse when compared to other donor/recipient KIR3DL1/HLA-Bw pairings with low or absent inhibitory signal (KIR3DL1-LOW/NO). (Giglio F et al, ASH Annual Meeting Abstracts, 2012) Here, we evaluated whether it was feasible to prospectively type and use KIR3DL1 allotypes in unrelated allo HCT donor selection, and whether this intervention would result in improved outcomes in patients undergoing transplant for AML and MDS. We performed PCR-SSP based intermediate resolution KIR3DL1 allele typing on all unrelated adult donors evaluated for patients with MDS and AML at our center from 2013 to present as previously described. (Boudreau J et al, PLoS One, 2014) KIR3DL1 status was provided to the treating physicians, who made the final donor selection. A total of 941 prospective allo HCT donors underwent high resolution HLA typing and KIR3DL1 allotyping for 252 patients (median per patient = 4, range 1-12). Among all donors evaluated, 27% were found to be KIR3DL1-HIGH when considering the respective recipient HLA-Bw. Having multiple donors evaluated improved the likelihood of avoiding a KIR3DL1-HIGH donor: Among recipients with one donor evaluated, 27% had only KIR3DL1-HIGH donors available compared to 12% in recipients with 2-3 donors evaluated and 4% for recipients with >3 donors evaluated (P < 0.0001). Among all evaluated patients, 41% had both KIR3DL1-HIGH and KIR3DL1-LOW/NO donors available, indicating a potential selection based on KIR3DL1 was possible. Among 252 patients evaluated, 115 proceeded to allo HCT (48 with MDS, 67 with AML). The median age at transplant was 62 years (range 3.6-78). Donors were HLA matched in 105 transplants and were single loci mismatched in 10 transplants. Conditioning was myeloablative in 73 (11 with total body irradiation). GVHD prophylaxis was with ex vivo CD34+ selection in 65 patients and with tacrolimus/methotrexate in the remaining patients. The median follow-up in transplanted patients was 13.1 months (range 0.5-43.3 months). On univariate analysis, the 2-year disease-free survival was 64% (95% confidence interval: 54-76%) in those with KIR3DL1-LOW/NO donors versus 39% (22-68%) in recipients with KIR3DL1-HIGH donors (P = 0.05). The incidence of relapse was similar but favored patients with KIR3DL1-LOW/NO donors (26% [15-37%] versus 35% [13-57%], P = 0.5). 2-year overall survival was similar between those with KIR3DL1-LOW/NO versus KIR3DL1-HIGH donors (75% [65-86%] versus 69% [52-91%], P = 0.43). The time from the initiation of a formalized donor search to transplant did not differ between recipients with KIR3DL1-LOW/NO versus KIR3DL1-HIGH donors (median 81 v. 83 days, respectively, P = 0.97). Recipients with KIR3DL1-LOW/NO donors were CIBMTR Transplant Risk Score low = 53, intermediate = 6, and high = 33; whereas recipients of KIR3DL1-HIGH donors were low = 17, intermediate = 2, and high = 4 (P = 0.15). These results indicate that disease severity and transplant urgency did not influence whether a KIR3DL1-LOW/NO donor was able to be selected. In summary, these prospective data on 115 patients from a single center support improved outcomes in patients with AML and MDS undergoing unrelated donor allo HCT using a donor with low or absent KIR3DL1 inhibition. A multi-center, prospective study to evaluate the prospective use of HLA and KIR genotype based selection of URDs for patients undergoing allo HCT for AML is underway (NCT02450708). Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Kernan: Gentium: Research Funding; The National Cancer Institute of the National Institutes of Health: Research Funding.

Lymph nodes (LNs) have been long considered as comprising few invariant NKT (iNKT) cells, and these cells have not been studied extensively. In this study, we unravel the existence of stable rather than transitional LN-resident NK1.1(-) iNKT cell populations. We found the one resident in peripheral LNs (PLNs) to comprise a major IL-17-producing population and to express the retinoic acid receptor-related orphan receptor (gamma)t (ROR(gamma)t). These cells respond to their ligand alpha-galactosylceramide (alpha-GalCer) in vivo by expanding dramatically in the presence of LPS, providing insight into how this rare population could have an impact in immune responses to infection. PLN-resident ROR(gamma)t(+) NK1.1(-) iNKT cells express concomitantly CCR6, the integrin alpha-chain alpha(E) (CD103), and IL-1R type I (CD121a), indicating that they might play a role in inflamed epithelia. Accordingly, skin epithelia comprise a major ROR(gamma)t(+) CCR6(+)CD103(+)CD121a(+) NK1.1(-) cell population, reflecting iNKT cell composition in PLNs. Importantly, both skin and draining PLN ROR(gamma)t(+) iNKT cells respond preferentially to inflammatory signals and independently of IL-6, indicating that they could play a nonredundant role during inflammation. Overall, our study indicates that ROR(gamma)t(+) iNKT cells could play a major role in the skin during immune responses to infection and autoimmunity.

International audience; Invariant natural killer T (iNKT) cells constitute a distinct subset of T lymphocytes exhibiting important immune-regulatory functions. Although various steps of their differentiation have been well characterized, the factors controlling their development remain poorly documented. Here, we show that TGF-beta controls the differentiation program of iNKT cells. We demonstrate that TGF-beta signaling carefully and specifically orchestrates several steps of iNKT cell development. In vivo, this multifaceted role of TGF-beta involves the concerted action of different pathways of TGF-beta signaling. Whereas the Tif-1gamma branch controls lineage expansion, the Smad4 branch maintains the maturation stage that is initially repressed by a Tif-1gamma/Smad4-independent branch. Thus, these three different branches of TGF-beta signaling function in concert as complementary effectors, allowing TGF-beta to fine tune the iNKT cell differentiation program.

Probiotics are believed to alleviate allergic and inflammatory skin disorders, but their impact on pathogenic effector T cells remains poorly documented. Here we show that oral treatment with the probiotic bacteria L. casei (DN-114 001) alone alleviates antigen-specific skin inflammation mediated by either protein-specific CD4(+) T cells or hapten-specific CD8(+) T cells. In the model of CD8(+) T cell-mediated skin inflammation, which reproduces allergic contact dermatitis in human, inhibition of skin inflammation by L. casei is not due to impaired priming of hapten-specific IFNgamma-producing cytolytic CD8(+) effector T cells. Alternatively, L. casei treatment reduces the recruitment of CD8(+) effector T cells into the skin during the elicitation (i.e. symptomatic) phase of CHS. Inhibition of skin inflammation by L. casei requires MHC class II-restricted CD4(+) T cells but not CD1d-restricted NK-T cells. L casei treatment enhanced the frequency of FoxP3(+) Treg in the skin and increased the production of IL-10 by CD4(+)CD25(+) regulatory T cells in skin draining lymph nodes of hapten-sensitized mice. These data demonstrate that orally administered L. casei (DN-114 001) efficiently alleviate T cell-mediated skin inflammation without causing immune suppression, via mechanisms that include control of CD8(+) effector T cells and involve regulatory CD4(+) T cells. L. casei (DN-114 001) may thus represent a probiotic of potential interest for immunomodulation of T cell-mediated allergic skin diseases in human.

Members of the killer immunoglobulin family (KIR) and their HLA class I ligands contribute to establishing natural killer cell reactive potential. NK cells bearing inhibitory KIR that bind self-HLA are termed “licensed” and are highly responsive to targets lacking self HLA, but tolerant to autologous, healthy cells. Among KIR:HLA partnerships, KIR3DL1 and HLA-Bw4 alleles demonstrate the greatest polymorphism. Allelic subgroups of KIR3DL1 are distinguished by their density on the surface of NK cells and demonstrate different sensitivity to inhibition by HLA-Bw4 allotypes. Specifically, KIR3DL1 alleles expressed with high surface density (3DL1high) are more potently inhibited by HLA-Bw4 epitopes possessing isoleucine (80I) compared with threonine (80T) at position 80. It is not currently known whether the same KIR-HLA interactions that mediate higher inhibitory response also endow higher effector capacity. Retrospective analyses of patients with HIV have demonstrated that the same allelic combinations of HLA-B and KIR3DL1 predictive of high inhibition are associated with delayed progression to AIDS. Indeed, a potential target for NK cells is created by the HIV nef protein, which mediates downregulation of HLA-B expression. Taken together, these finding have led us to hypothesize that the sensitivity of NK cells for inhibition by HLA predicts the extent to which they may be licensed for functional responsiveness. We undertook functional analyses of NK cells exclusively expressing KIR3DL1 from healthy HLA-Bw4+ or Bw4-/- donors, using HLA-negative 721.221 target cells to examine licensing function. First, we developed and validated a multiplex PCR array allowing identification of allelic groups of KIR3DL1 that correspond to expression densities. This genomic analysis informed the division of 59 subjects into groups stratified by the inhibitory potential conveyed by self HLA-B and KIR3DL1+ alleles. As expected and consistent with NK education or “licensing” by self-specific inhibitory KIR with cognate HLA ligand, KIR3DL1+Bw4+ NK cells demonstrated greater responsiveness 721.221 cells compared with KIR3DL1+ cells obtained from Bw4-/- donors, as assessed by CD107α externalization. The proportion of KIR3DL1+ NK cells degranulating in response to HLA class I-negative target cells was highly variable and not reflective of either HLA-Bw4 nor KIR3DL1 allele groups alone; however, when both KIR3DL1 and Bw4 allele groups were considered, highly inhibitory allotype pairs were indeed associated with higher NK effector function (p=0.0065). This finding was particularly pronounced among partnerships involving high-density KIR3DL1 alleles: compared with 80T, 80I conditioned 3DL1high NK cells for superior 721-221-stimulated degranulation (p=0.0035). We further investigated whether NK cell licensing could be mediated and/or maintained by HLA intrinsic to NK cells. We found that diminution of HLA expression in licensed KIR3DL1+ by shRNA-mediated knockdown reduced responsiveness to HLA class I-negative target cells, demonstrating that HLA is required on NK cells to maintain their licensed potential. Collectively, these findings reveal that an NK cell’s capacity for effector response is not only determined by the presence of a self-specific receptor, but that functional hierarchies exist among NK cells bearing different allotypes of one KIR for its ligand in a manner correlated with inhibitory capacity. Finally, cis-interactions between KIR and HLA contribute to NK licensing, indicating that human NK education is at least partly determined by molecules intrinsic to the cell itself. These findings of differential NK licensing among KIR3DL1-Bw4 allotype combinations now provide the biological basis for the clinical findings of variable HIV control among patients with different KIR3DL1-Bw4 allotype combinations. Disclosures: No relevant conflicts of interest to declare.