A Bio-Liposome Activating Natural Killer Cell by Illuminating Tumor Homogenization Antigen Properties

Natural killer (NK) cell therapies, primarily based on chimeric antigen receptor NK cells (CAR-NK), have been developed and applied clinically for therapeutic treatment of patients with mid-to-late-stage tumors. However, NK cell therapy has limited efficacy due to insufficient antigen expression on the tumor cell surface. Here, a universal "illuminate tumor homogenization antigen properties" (ITHAP) strategy to achieve stable and controlled antigen expression on the surface of tumor cells using nanomedicine, thus significantly enhancing the immune recognizability of tumor cells, is described. The ITHAP strategy is used to generate bio-liposomes (Pt@PL-IgG) composed of intermingled platelet membranes and liposomes with NK-activatable target antigen (IgG antibodies) and cisplatin pre-drug. It is demonstrated that Pt@PL-IgG successfully targets tumor cells using the autonomous drive of platelet membranes and achieves IgG implantation on tumor cells by utilizing membrane fusion properties. Moreover, it is shown that the Pt-DNA complex combined with NK cell-induced pyroptosis causes substantial interferon (IFN) secretion, thus providing a synthase-stimulator of interferon genes (STING)-IFN-mediated positive immune microenvironment to further potentiate NK therapy. These results show that anchoring cancer cells with NK-activatable target antigens is a promising translational strategy for addressing therapeutic challenges in tumor heterogeneity.

Multiomic analysis reveals cell-type-specific molecular determinants of COVID-19 severity

The determinants of severe COVID-19 in healthy adults are poorly understood, which limits the opportunity for early intervention. We present a multiomic analysis using machine learning to characterize the genomic basis of COVID-19 severity. We use single-cell multiome profiling of human lungs to link genetic signals to cell-type-specific functions. We discover >1,000 risk genes across 19 cell types, which account for 77% of the SNP-based heritability for severe disease. Genetic risk is particularly focused within natural killer (NK) cells and T cells, placing the dysfunction of these cells upstream of severe disease. Mendelian randomization and single-cell profiling of human NK cells support the role of NK cells and further localize genetic risk to CD56bright NK cells, which are key cytokine producers during the innate immune response. Rare variant analysis confirms the enrichment of severe-disease-associated genetic variation within NK-cell risk genes. Our study provides insights into the pathogenesis of severe COVID-19 with potential therapeutic targets.

Synthetic DNA for Cell Surface Engineering: Experimental Comparison between Click Conjugation and Lipid Insertion in Terms of Cell Viability, Engineering Efficiency, and Displaying Stability

The cell surface can be engineered with synthetic DNA for various applications ranging from cancer immunotherapy to tissue engineering. However, while elegant methods such as click conjugation and lipid insertion have been developed to engineer the cell surface with DNA, little effort has been made to systematically evaluate and compare these methods. Resultantly, it is often challenging to choose a right method for a certain application or to interpret data from different studies. In this study, we systematically evaluated click conjugation and lipid insertion in terms of cell viability, engineering efficiency, and displaying stability. Cells engineered with both methods can maintain high viability when the concentration of modified DNA is less than 25-50 μM. However, lipid insertion is faster and more efficient in displaying DNA on the cell surface than click conjugation. The efficiency of displaying DNA with lipid insertion is 10-40 times higher than that with click conjugation for a large range of DNA concentration. However, the half-life of physically inserted DNA on the cell surface is 3-4 times lower than that of covalently conjugated DNA, which depends on the working temperature. While the half-life of physically inserted DNA molecules on the cell surface is shorter than that of DNA molecules clicked onto the cell surface, lipid insertion is more effective than click conjugation in the promotion of cell-cell interactions under the two different experimental settings. The data acquired in this work are expected to act as a guideline for choosing an approximate method for engineering the cell surface with synthetic DNA or even other biomolecules.

Comprehensive Analyses of Type 1 Diabetes Ketosis- or Ketoacidosis-Related Genes in Activated CD56+CD16+ NK Cells

OBJECTIVES

Alterations in natural killer (NK) cells activity cause damage to pancreatic islets in type 1 diabetes mellitus (T1DM). The aim of this study is to identify T1DM ketosis- or ketoacidosis-related genes in activated CD56⁺CD16⁺ NK cells.

METHODS

Microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were analyzed using the GEO2R tool. Enrichment analyses were performed using Metascape online database and GSEA software. Cell-specific gene co-expression network was built using NetworkAnalyst tools. Cytoscape software was used to identify hub genes and construct co-expressed networks. Target miRNAs were predicted based on the DIANA-micro T, miRDB, and miRWalk online databases.

RESULTS

A total of 70 DEGs were identified between T1DM patients recovered from ketosis or ketoacidosis and healthy control blood samples in GSE44314. Among the DEGs, 10 hub genes were screened out. The mature NK cell-specific gene co-expression network for DEGs in T1DM was built using NetworkAnalyst tools. DEGs between activated CD56⁺CD16⁺ NK cells and CD56^brightCD16^- NK cells were identified from GSE1511. After intersection, 13 overlapping genes between GSE44314 and GSE1511 microarray datasets were screened out, in which 7 hub genes were identified. Additionally, 59 target miRNAs were predicted according to the 7 hub genes. After validating with the exosome miRNA expression profile dataset of GSE97123, seven differentially expressed miRNAs (DEmiRNAs) in plasma-derived exosome were selected. Finally, a mRNA-miRNA network was constructed, which was involved in the T1DM ketosis or ketoacidosis process.

CONCLUSION

This work identified seven hub genes in activated CD56⁺CD16⁺ NK cells and seven miRNAs in plasma-derived exosome as potential predictors of T1DM ketoacidosis, which provided a novel insight for the pathogenesis at the transcriptome level.

Effectual Labeling of Natural Killer Cells with Upconverting Nanoparticles by Electroporation for In Vivo Tracking and Biodistribution Assessment

Natural killer (NK) cells, which are cytotoxic lymphocytes of the innate immune system and recognize cancer cells via various immune receptors, are promising agents in cell immunotherapy. To utilize NK cells as a therapeutic agent, their biodistribution and pharmacokinetics need to be evaluated following systemic administration. Therefore, in vivo imaging and tracking with efficient labeling and quantitative analysis of NK cells are required. However, the lack of the phagocytic capacity of NK cells makes it difficult to establish breakthroughs in cell labeling and subsequent in vivo studies. Herein, an effective labeling of upconverting nanoparticles (UCNPs) in NK cells is proposed using electroporation with high sensitivity and stability. The labeling performance of UCNPs functionalized with carboxy-polyethylene glycol (PEG) is better than with methoxy-PEG or with amine-PEG. The labeling efficiency becomes higher, but cell damage is greater as electric field increases; thus, there is an optimum electroporation condition for internalization of UCNPs into NK cells. The tracking and biodistribution imaging analyses of intravenously injected NK cells show that the labeled NK cells are initially distributed primarily in lungs and then spread to the liver and spleen. These advances will accelerate the application of NK cells as key components of immunotherapy against cancer.

Cryopreservation impairs 3-D migration and cytotoxicity of natural killer cells

Natural killer (NK) cells are important effector cells in the immune response to cancer. Clinical trials on adoptively transferred NK cells in patients with solid tumors, however, have thus far been unsuccessful. As NK cells need to pass stringent safety evaluation tests before clinical use, the cells are cryopreserved to bridge the necessary evaluation time. Standard degranulation and chromium release cytotoxicity assays confirm the ability of cryopreserved NK cells to kill target cells. Here, we report that tumor cells embedded in a 3-dimensional collagen gel, however, are killed by cryopreserved NK cells at a 5.6-fold lower rate compared to fresh NK cells. This difference is mainly caused by a 6-fold decrease in the fraction of motile NK cells after cryopreservation. These findings may explain the persistent failure of NK cell therapy in patients with solid tumors and highlight the crucial role of a 3-D environment for testing NK cell function.

3D Nanochannel Electroporation for Macromolecular Nucleotide Delivery

Delivery of macromolecular nucleotides into the living cells holds a great promise for the development of new therapeutics. However, its abilities for adoptive immunotherapy, cell reprogramming, and primary cell transfection have been long-term hindered by the lack of a system that can locally deliver engineered therapeutic nucleotides (e.g., plasmids, siRNAs, miRNAs) without causing any side effects. In this chapter, the performance of a novel 3D nanoelectroporation system (3D NEP) is highlighted in three scenarios-adoptive immunotherapy, cell reprogramming, and adult mouse primary cardiomyocyte transfection. Detailed protocols were given to introduce the 3D NEP system assembly, as well as their applications in (1) natural killer (NK) cells transfection by delivery of chimeric antigen receptor (CAR) plasmids; (2) mouse embryonic fibroblasts transfection with OSKM factors; and (3) miR-29b molecular beacon (BMs) delivery into primary cardiomyocytes for interrogating the side effect of miR-29b-assisted treatment.

VS38 Identifies Myeloma Cells With Dim CD38 Expression and Plasma Cells Following Daratumumab Therapy, Which Interferes With CD38 Detection for 4 to 6 Months

OBJECTIVES

We report our institutional experience using VS38 to evaluate plasma cells by flow cytometry.

METHODS

Flow cytometry data were reanalyzed to compare plasma cell percentages between the standard panel and VS38 panel. Natural killer (NK) and plasma cell CD38 median fluorescence intensity (MFI) values were calculated.

RESULTS

Our cohort included 63 specimens from 38 patients. Twenty-six had received daratumumab (monoclonal anti-CD38 therapy) between less than 1 month and 17 months prior. For NK and plasma cells, CD38 MFI values were suppressed for 0 to 4 months and started to increase 4 to 6 months after last exposure. There was no significant difference in clonal plasma cell percentage calculated by the VS38 and standard panels; however, identification and quantification using the VS38 panel were easier.

CONCLUSIONS

VS38 is a viable alternative to bright CD38 to identify plasma cells and particularly helpful in myeloma cases with dim CD38 and after daratumumab. Daratumumab interference with CD38 identification persists 4 to 6 months after the last exposure.

Cell-Membrane Immunotherapy Based on Natural Killer Cell Membrane Coated Nanoparticles for the Effective Inhibition of Primary and Abscopal Tumor Growth

Developing effective immunotherapies with low toxicity and high tumor specificity is the ultimate goal in the battle against cancer. Here, we reported a cell-membrane immunotherapy strategy that was able to eliminate primary tumors and inhibited distant tumors by using natural killer (NK) cell membrane cloaked photosensitizer 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl) tetrakis (benzoic acid) (TCPP)-loaded nanoparticles (NK-NPs). The proteomic profiling of NK cell membranes was performed through shotgun proteomics, and we found that NK cell membranes enabled the NK-NPs to target tumors and could induce or enhance pro-inflammatory M1-macrophages polarization to produce antitumor immunity. The TCPP loaded in NK-NPs could induce cancer cell death through photodynamic therapy and consequently enhanced the antitumor immunity efficiency of the NK cell membranes. The results confirmed that NK-NPs selectively accumulated in the tumor and were able to eliminate primary tumor growth and produce an abscopal effect to inhibit distant tumors. This cell-membrane immunotherapeutic approach offers a strategy for tumor immunotherapy.

Persistent infection due to a small-colony variant of Burkholderia pseudomallei leads to PD-1 upregulation on circulating immune cells and mononuclear infiltration in viscera of experimental BALB/c mice

Background

Melioidosis is a neglected tropical disease endemic across South East Asia and Northern Australia. The etiological agent, Burkholderia pseudomallei (B.pseudomallei), is a Gram-negative, rod-shaped, motile bacterium residing in the soil and muddy water across endemic regions of the tropical world. The bacterium is known to cause persistent infections by remaining latent within host cells for prolonged duration. Reactivation of the recrudescent disease often occurs in elders whose immunity wanes. Moreover, recurrence rates in melioidosis patients can be up to ~13% despite appropriate antibiotic therapy, suggestive of bacterial persistence and inefficacy of antibiotic regimens. The mechanisms behind bacterial persistence in the host remain unclear, and hence understanding host immunity during persistent B. pseudomallei infections may help designing potential immunotherapy.

Methodology/Principal findings

A persistent infection was generated using a small-colony variant (SCV) and a wild-type (WT) B. pseudomallei in BALB/c mice via intranasal administration. Infected mice that survived for >60 days were sacrificed. Lungs, livers, spleens, and peripheral blood mononuclear cells were harvested for experimental investigations. Histopathological changes of organs were observed in the infected mice, suggestive of successful establishment of persistent infections. Moreover, natural killer (NK) cell frequency was increased in SCV- and WT-infected mice. We observed programmed death-1 (PD-1) upregulation on B cells of SCV- and WT-infected mice. Interestingly, PD-1 upregulation was only observed on NK cells and monocytes of SCV-infected mice. In contrast, cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) downregulation was seen on NK cells of WT-infected mice, and on monocytes of SCV- and WT-infected mice.

Conclusions/Significance

The SCV and the WT of B. pseudomallei distinctly upregulated PD-1 expression on B cells, NK cells, and monocytes to dampen host immunity, which likely facilitates bacterial persistence. PD-1/PD-L1 pathway appears to play an important role in the persistence of B. pseudomallei in the host.

B. pseudomallei is a bacterium that causes melioidosis, a disease endemic in Southeastern Asia and Northern Australia. It is estimated that melioidosis leads to 89,000 deaths worldwide each year. Nevertheless, melioidosis continues to remain a neglected tropical disease that is not even on the list of neglected tropical diseases of the World Health Organization. Furthermore, the disease has a high mortality and recurrence rate, which can be up to 40% and 13%, respectively. It has also been well documented that B. pseudomallei causes latent/persistent infections for a prolonged period without showing apparent symptoms in the infected individual. The mechanisms that are responsible for bacterial persistence in the host remain unclear. Our results demonstrated that B. pseudomallei were able to upregulate PD-1 expression on B cells, NK cells, and/or monocytes during persistent diseases, which likely diminish optimal host immunity. The weakened host immunity in turns facilitates persistence of the bacterium. Interestingly, the SCV had a higher PD-1 expression on distinct immune cells compared to the WT, which might explain its frequent association with persistent infections. Immunotherapies by targeting PD-1/PD-L1 pathway could serve as a better treatment than the conventional antibiotic regimens, which cause a high rate of recurrence in melioidosis patients.

Compromised natural killer cells in pulmonary embolism

OBJECTIVE

The high morbidity, mortality and misdiagnosis rate render pulmonary embolism (PE) as a worldwide health problem. However, the etiology and pathogenesis of this disease have not been well characterized. Increasing studies indicate infection and immunity play a crucial role in PE. Natural killer (NK) cells act as a bridge between the innate immune and acquired immune. This study aimed to investigate the possible function of NK cells in PE.

METHODS

Human cDNA microarray analysis was employed to detect genes associated with NK cells in peripheral blood mononuclear cells (PBMCs). Random variance model corrected t-test was used for statistical analysis of differential gene expression. Flow cytometry was performed to detect the CD16+CD56+ NK cells.

RESULTS

In the present study, based on gene expression microarray analysis, we showed four inhibitory receptors (KLRB1, KLRD1, KLRF1, KLRG1) and four activating receptors (KLRC1, KLRC3, KLRK1 and NCR1) on NK cells were remarkably down-regulated and the cytological experiment demonstrated the proportion of CD16+CD56+ NK cells among PBMCs decreased in the PE group.

CONCLUSIONS

We confirmed the presence of reduced expression of critical activating as well as inhibitory NK cell receptors and low proportion of CD16+CD56+ NK cells in PE. The consistence between genomic and cytological examination suggests compromised NK cells may contribute to the pathogenesis of PE.

Nkrp1 family, from lectins to protein interacting molecules

The C-type lectin-like receptors include the Nkrp1 protein family that regulates the activity of natural killer (NK) cells. Rat Nkrp1a was reported to bind monosaccharide moieties in a Ca²⁺-dependent manner in preference order of GalNac > GlcNAc >> Fuc >> Gal > Man. These findings established for rat Nkrp1a have been extrapolated to all additional Nkrp1 receptors and have been supported by numerous studies over the past two decades. However, since 1996 there has been controversy and another article showed lack of interactions with saccharides in 1999. Nevertheless, several high affinity saccharide ligands were synthesized in order to utilize their potential in antitumor therapy. Subsequently, protein ligands were introduced as specific binders for Nkrp1 proteins and three dimensional models of receptor/protein ligand interaction were derived from crystallographic data. Finally, for at least some members of the NK cell C-type lectin-like proteins, the “sweet story” was impaired by two reports in recent years. It has been shown that the rat Nkrp1a and CD69 do not bind saccharide ligands such as GlcNAc, GalNAc, chitotetraose and saccharide derivatives (GlcNAc-PAMAM) do not directly and specifically influence cytotoxic activity of NK cells as it was previously described.

Systemic Epstein-Barr virus-positive T/natural killer-cell lymphoproliferative disorder: a case report and review of literature

Systemic Epstein-Barr virus-positive T/natural killer-cell lymphoproliferative disorder (EBV + LPD) has predominantly been observed among pediatric patients as a life-threatening condition. The present study presents a rare case of EBV + LPD in an adult with good outcome. This patient's history is more than 2 years and her condition was stable. She received 6 cycles of chemotherapy cyclophosphamide/doxorubicin/vincristine/prednisolone (CHOP). The evaluation was complete remission. The low levels of EBV-DNA in the peripheral blood may have potential benefit factor for the sensitivity to the chemotherapy and good outcome.

Isolation and characterization of CD34+ blast-derived exosomes in acute myeloid leukemia

Exosomes are membrane-bound vesicles found in all biological fluids. AML patients' plasma collected at diagnosis contains elevated exosome levels relative to normal donor (ND) plasma. The molecular profile of AML exosomes changes in the course of therapy and may serve as a measure of disease progression or response to therapy. However, plasma contains a mix of exosomes derived from various cell types. To be able to utilize blast-derived exosomes as biomarkers for AML, we have developed an immunoaffinity-based capture method utilizing magnetic microbeads coated with anti-CD34 antibody (Ab). This Ab is specific for CD34, a unique marker of AML blasts. The capture procedure was developed using CD34+ exosomes derived from Kasumi-1 AML cell culture supernatants. The capture capacity of CD34microbeads was shown to linearly correlate with the input exosomes. A 10 uL aliquot of CD34 microbeads was able to capture all of CD34+ exosomes present in 100-1,000 uL of AML plasma. The levels of immunocaptured CD34+ exosomes correlated with the percentages of CD34+ blasts in the AML patients' peripheral blood. The immunocaptured exosomes had a typical cup-shaped morphology by transmission electron microscopy, and their molecular cargo was similar to that of parental blasts. These exosomes were biologically-active. Upon co-incubation with natural killer (NK) cells, captured blast-derived exosomes down-regulated surface NKG2D expression, while non-captured exosomes reduced expression levels of NKp46. Our data provide a proof-of-principle that blast-derived exosomes can be quantitatively recovered from AML patients' plasma, their molecular profile recapitulates that of autologous blasts and they retain the ability to mediate immune suppression. These data suggest that immunocaptured blast-derived exosomes might be useful in diagnosis and/or prognosis of AML in the future.

Experimental infection of rhesus macaques and common marmosets with a European strain of West Nile virus

West Nile virus (WNV) is a mosquito-borne flavivirus that infects humans and other mammals. In some cases WNV causes severe neurological disease. During recent years, outbreaks of WNV are increasing in worldwide distribution and novel genetic variants of the virus have been detected. Although a substantial amount of data exists on WNV infections in rodent models, little is known about early events during WNV infection in primates, including humans. To gain a deeper understanding of this process, we performed experimental infections of rhesus macaques and common marmosets with a virulent European WNV strain (WNV-Ita09) and monitored virological, hematological, and biochemical parameters. WNV-Ita09 productively infected both monkey species, with higher replication and wider tissue distribution in common marmosets compared to rhesus macaques. The animals in this study however, did not develop clinical signs of WNV disease, nor showed substantial deviations in clinical laboratory parameters. In both species, the virus induced a rapid CD56^dimCD16^bright natural killer response, followed by IgM and IgG antibody responses. The results of this study show that healthy rhesus macaques and common marmosets are promising animal models to study WNV-Ita09 infection. Both models may be particularly of use to evaluate potential vaccine candidates or to investigate WNV pathogenesis.

West Nile virus (WNV) is a mosquito-borne virus that can infect mammals, including humans. Most infected humans do not develop disease, but in about 20% of cases humans develop WNV-related disease symptoms, varying in severity from fever to a sometimes life-threatening neuro-invasive disease. The number of WNV infections in Europe has increased in recent years and is caused by viruses that are genetically different from the viruses that caused the WNV epidemic in North America. In this study, we have experimentally infected two different monkey species, rhesus macaques and common marmosets, with the European WNV isolate Ita09 to evaluate the early events after infection and the onset of the disease. Both species were equally susceptible to infection with WNV-Ita09, but differences between species were observed. Compared to rhesus macaques, common marmosets had higher virus loads in blood, and presented a wider distribution of the virus in various organs. Based on the analysis of virological, immunological, biochemical and hematological parameters, we conclude that rhesus macaques as well as common marmosets are potentially useful animal models to evaluate vaccine candidates or to investigate WNV pathogenesis.

The structure of cytomegalovirus immune modulator UL141 highlights structural Ig-fold versatility for receptor binding

Natural killer (NK) cells are critical components of the innate immune system as they rapidly detect and destroy infected cells. To avoid immune recognition and to allow long-term persistence in the host, Human cytomegalovirus (HCMV) has evolved a number of genes to evade or inhibit immune effector pathways. In particular, UL141 can inhibit cell-surface expression of both the NK cell-activating ligand CD155 as well as the TRAIL death receptors (TRAIL-R1 and TRAIL-R2). The crystal structure of unliganded HCMV UL141 refined to 3.25 Å resolution allowed analysis of its head-to-tail dimerization interface. A `dimerization-deficient' mutant of UL141 (ddUL141) was further designed, which retained the ability to bind to TRAIL-R2 or CD155 while losing the ability to cross-link two receptor monomers. Structural comparison of unliganded UL141 with UL141 bound to TRAIL-R2 further identified a mobile loop that makes intimate contacts with TRAIL-R2 upon receptor engagement. Superposition of the Ig-like domain of UL141 on the CD155 ligand T-cell immunoreceptor with Ig and ITIM domains (TIGIT) revealed that UL141 can potentially engage CD155 similar to TIGIT by using the C'C'' and GF loops. Further mutations in the TIGIT binding site of CD155 (Q63R and F128R) abrogated UL141 binding, suggesting that the Ig-like domain of UL141 is a viral mimic of TIGIT, as it targets the same binding site on CD155 using similar `lock-and-key' interactions. Sequence alignment of the UL141 gene and its orthologues also showed conservation in this highly hydrophobic (L/A)X6G `lock' motif for CD155 binding as well as conservation of the TRAIL-R2 binding patches, suggesting that these host-receptor interactions are evolutionary conserved.

Sweeping lymph node micrometastases off their feet: an engineered model to evaluate natural killer cell mediated therapeutic intervention of circulating tumor cells that disseminate to the lymph nodes

Approximately 90% of cancer related deaths are due to metastasis. Cells from the primary tumor can metastasize through either the vascular or lymphatic circulation. Cancer cells in circulation are called circulating tumor cells (CTCs) and it has been shown that bone marrow is a niche for homing of blood borne CTCs from several epithelial tumors. Cancer cells found in bone marrow are termed disseminated tumor cells (DTCs). Likewise, CTCs in the lymphatic circulation are more often seeded in the sentinel lymph nodes (SLN) that drain the tumor. Micrometastases (<2 mm) occur after the arrest and implantation of DTCs in lymph nodes over time. This paper presents a cell culture platform termed microbubbles formed in polydimethylsiloxane (PDMS) from a microfabricated silicon wafer for mimicking lymph node micrometastases. We cultured lymph node seeking cancer cells in microbubbles to evaluate the efficacy of natural killer (NK) mediated therapy for targeting lymph node micrometastasis. The microbubble platform consists of an array of microcavities that provides a unique microenvironment for mimicking the deep cortical unit of the lymph nodes. We show that cancer cells cultured in microbubbles with therapeutic NK cells undergo apoptosis after 24 h in culture. Since lymph node metastases are prevalent across several types of cancer, this platform may be useful for developing improved cancer therapies for targeting lymph node micrometastases.

The role of hair follicle immune privilege collapse in alopecia areata: status and perspectives

Alopecia areata (AA) may represent a CD8+T cell-mediated, organ-specific autoimmune disease in which as yet elusive autoantigens are recognized, once they become exposed by ectopic major histocompatibility complex class I expression by anagen hair follicles (HFs) that have lost their relative immune privilege (IP). On this basis, AA research is chiefly challenged with identifying the autoreactive CD8+T cells and their cognate autoantigens as well as key inducers of HF-IP collapse and "HF-IP guardians" that prevent and/or can restore IP collapse. However, natural killer group 2D-positive (NKG2D+) cells (incl. NK, NKT, and CD8+T cells) and NKG2D-activating ligands from the MICA (MHC I-related chain A) family may also have a key role in AA pathogenesis, as a massive infiltrate of IFN-γ-secreting NKG2D+ cells alone suffices to induce the AA phenotype. Therefore, we speculate that AA may represent a stereotypic, but distinct HF response pattern to inflammatory insults associated with HF-IP collapse.

A new humanized mouse model for alopecia areata

Although alopecia areata (AA) is not life threatening, it may lead to severe psychological disturbances, reducing the quality of life in all ages. Thus, a new animal model is needed for shedding more light onto the pathogenesis of this cell-mediated, organ-specific autoimmune disease to identify more effective therapeutic strategies. Recently, we succeeded in developing a new humanized mouse model of AA, which includes transplantation of healthy human scalp skin obtained from normal volunteers on to severe-combined immunodeficient mice. This is followed by intradermal injection of either autologous or allogeneic peripheral blood mononuclear cells, which had been cultured with high dose of IL-2 and enriched for natural killer group 2D-positive (NKG2D+) and CD56+ cells. This protocol leads to rapid and predictable development of focal hair loss, with all the characteristic clinical, histological, and immunohistochemical features of AA. This humanized mouse AA model underscores the functional importance of NKG2D+ and CD56+ cells in AA pathogenesis and promises to be instrumental for identifying novel AA treatment strategies.

[Myeloid/natural killer cell precursor acute leukemia diagnosed by cell marker analysis]

We report a case of myeloid/natural killer cell precursor acute leukemia. A 68-year-old man was diagnosed as having lymphoma in his neck, and was referred to our department for further examination and treatment. After admission, blastoid-cells appeared and increased rapidly in his peripheral blood. Cell marker analysis revealed that the blastoid-cells expressed CD7, CD56, CD33, and CD34. He was then diagnosed with myeloid/natural killer cell precursor leukemia. This form of leukemia was recently established as a distinct disease entity. Further clinicopathological evaluation and the establishment of treatment are necessary.

Nanoscale ligand spacing influences receptor triggering in T cells and NK cells

Bioactive nanoscale arrays were constructed to ligate activating cell surface receptors on T cells (the CD3 component of the TCR complex) and natural killer (NK) cells (CD16). These arrays are formed from biofunctionalized gold nanospheres with controlled interparticle spacing in the range 25-104 nm. Responses to these nanoarrays were assessed using the extent of membrane-localized phosphotyrosine in T cells stimulated with CD3-binding nanoarrays and the size of cell contact area for NK cells stimulated with CD16-binding nanoarrays. In both cases, the strength of response decreased with increasing spacing, falling to background levels by 69 nm in the T cell/anti-CD3 system and 104 nm for the NK cell/anti-CD16 system. These results demonstrate that immune receptor triggering can be influenced by the nanoscale spatial organization of receptor/ligand interactions.

[Morpho-functional characteristics of human spleen (an immunohistochemical study)]

Using immunohistochemical and morphometric methods, the quantitative composition and structural localization of immunocompetent cells were studied in human spleen (n=20, autopsy material). The detailed morpho-functional characteristics of splenic white and red pulp are presented. Cell subpopulations of T (CD3+, CD4+, CD8+) and B lymphocytes (CD20+), natural killer cells (CD57+), tissue macrophages (CD68+) and dendritic cells (CD35+, S100+) were studied. An analysis of the correlations of immunocompetent cells in different regions of white and red pulp may become the basis for optimization of histopathological diagnosis definition in clinical practice

MHC class I target recognition, immunophenotypes and proteomic profiles of natural killer cells within the spleens of day-14 chick embryos

Chicken natural killer (NK) cells are not well defined, so little is known about the molecular interactions controlling their activity. At day 14 of embryonic development, chick spleens are a rich source of T-cell-free CD8αα(+), CD3(-) cells with natural killing activity. Cell-mediated cytotoxicity assays revealed complex NK cell discrimination of MHC class I, suggesting the presence of multiple NK cell receptors. Immunophenotyping of freshly isolated and recombinant chicken interleukin-2-stimulated d14E CD8αα(+) CD3(-) splenocytes provided further evidence for population heterogeneity. Complex patterns of expression were found for CD8α, chB6 (Bu-1), CD1-1, CD56 (NCAM), KUL01, CD5, and CD44. Mass spectrometry-based proteomics revealed an array of NK cell proteins, including the NKR2B4 receptor. DAVID and KEGG analyses and additional immunophenotyping revealed NK cell activation pathways and evidence for monocytes within the splenocyte cultures. This study provides an underpinning for further investigation into the specificity and function of NK cells in birds.

Kinome analysis of receptor-induced phosphorylation in human natural killer cells

BACKGROUND

Natural killer (NK) cells contribute to the defense against infected and transformed cells through the engagement of multiple germline-encoded activation receptors. Stimulation of the Fc receptor CD16 alone is sufficient for NK cell activation, whereas other receptors, such as 2B4 (CD244) and DNAM-1 (CD226), act synergistically. After receptor engagement, protein kinases play a major role in signaling networks controlling NK cell effector functions. However, it has not been characterized systematically which of all kinases encoded by the human genome (kinome) are involved in NK cell activation.

RESULTS

A kinase-selective phosphoproteome approach enabled the determination of 188 kinases expressed in human NK cells. Crosslinking of CD16 as well as 2B4 and DNAM-1 revealed a total of 313 distinct kinase phosphorylation sites on 109 different kinases. Phosphorylation sites on 21 kinases were similarly regulated after engagement of either CD16 or co-engagement of 2B4 and DNAM-1. Among those, increased phosphorylation of FYN, KCC2G (CAMK2), FES, and AAK1, as well as the reduced phosphorylation of MARK2, were reproducibly observed both after engagement of CD16 and co-engagement of 2B4 and DNAM-1. Notably, only one phosphorylation on PAK4 was differentally regulated.

CONCLUSIONS

The present study has identified a significant portion of the NK cell kinome and defined novel phosphorylation sites in primary lymphocytes. Regulated phosphorylations observed in the early phase of NK cell activation imply these kinases are involved in NK cell signaling. Taken together, this study suggests a largely shared signaling pathway downstream of distinct activation receptors and constitutes a valuable resource for further elucidating the regulation of NK cell effector responses.

Detailed characterisation of CB2 receptor protein expression in peripheral blood immune cells from healthy human volunteers using flow cytometry

It is commonly accepted from gene expression studies that the CB2 receptor is expressed by most cell types of the rodent and human immune system. However, the exact identity of cells expressing CB2 receptor protein in human blood or the abundance of receptors expressed by each immune subset is not well characterised. We conducted a detailed analysis of CB2 protein levels expressed by blood-derived immune cells from healthy human donors. Flow-cytometry was conducted using 4 commercially available anti-CB2 polyclonal antibodies in conjunction with a selection of immune cell specific markers. Across multiple healthy subjects we observed that NK cells, B-lymphocytes and monocytes expressed a higher level of CB2 receptor than CD4+ or CD8+ T-lymphocytes. Neutrophils also expressed a low level of CB2 receptor. NK cells had the greatest variation in CB2 expression levels, whereas for each of the other cell types CB2 levels were relatively similar between subjects. In contrast to other methods, the high sensitivity of flow-cytometry revealed that CB2 receptors are present on resting T-lymphocytes at low abundance in some healthy subjects. These data provide the first detailed analysis of CB2 protein levels in blood leukocyte subsets from healthy donors and identifies the cell types which could be targeted with CB-mimetic drugs in humans.

Defining the membrane proteome of NK cells

The present study was initiated to define the composition of the membrane proteome of the Natural Killer (NK) like cell line YTS. Isolated membranes were treated with reagents that have been reported to remove peripheral membrane proteins. Additional steps involving trifluoroethanol (TFE) were introduced in an effort to remove remaining nonintegral membrane proteins. This treatment resulted in the release of a subset of proteins without any apparent disruption of membrane integrity. The membranes were solubilized and digested with trypsin in 25% TFE. The resulting peptides were separated using an off-line two-dimensional reversed phase LC technique at alkaline and acidic pHs. Mass spectrometric analysis identified 1843 proteins with high confidence scores. On the basis of the presence of transmembrane regions or evidence of posttranslational modifications and prediction algorithms, approximately 40% of the identified proteins were predicted as plausible membrane proteins. The remaining species were largely involved in cellular processes and molecular functions that could be predicted to be transiently associated with membranes. The analytical approaches presented in this study offer robust generic methods for the identification and characterization of membrane proteins. These observations highlight the fact that the membrane is a dynamic entity that is composed of integral and stably associated proteins.

Enteropathy-Type T-Cell Lymphoma Expressing NK-Cell Intraepithelial Lymphocyte (NK-IEL) Phenotype

Enteropathy-type T-cell lymphoma (ETL) is an intraepithelial T-lymphocyte (T-IEL) tumor. The tumor cells are usually CD3+, CD4-, CD8+, and contain cytotoxic granule associated proteins. We report on a CD3-negative CD56-positive enteropathy-associated lymphoma (ETL). This is the first case report of CD3-negative, CD56-positive, CD94-negative, and CD161-positive ETL. ETL cells originate from intraepithelial T-lymphocytes of the intestine. CD3-negative intraepithelial lymphocytes are known as natural killer (NK)-IELs. The phenotype of NK-IELs is also CD3-negative, CD56-positive, CD94-negative, and CD161-positive, while most normal NK cells express CD56 and CD94. CD3-negative lymphoma cells in this report also expressed CD56 and CD161, but not CD94. Because Southern blotting analysis showed a rearrangement of T-cell receptor (TCR) Cbeta in this case, the tumor is classified as an ETL. Based on the findings, NK-IELs may originate from T-cells, not NK-cells.

HLA-E and HLA-E-bound peptides: recognition by subsets of NK and T cells

In humans, major histocompatibility complex (MHC) class I molecules comprise the classical (class Ia) human leukocyte antigens (HLA)-A, -B, and -C, and the non-classical (class Ib) HLA-E, -F, -G and -H (HFE) molecules. The best-characterized MHC class Ib molecule is HLA-E. HLA-E was first described as a non-polymorphic ligand of the CD94/NKG2 receptors expressed mainly by natural killer (NK) cells and its role was thus confined to the regulation of NK cell function. Therefore, interaction of HLA-E with the CD94/NKG2 receptors can result in either inhibition or activation of NK cells, depending on the peptide presented and on the NKG2 receptor CD94 is associated with. Thus, CD94/NKG2A functions as an inhibitory receptor, whereas CD94/NKG2C functions as an activating receptor. However, recent evidences obtained by our group and others indicated that HLA-E represents a novel restriction element for ab T-cell receptor (TCR)-mediated recognition. Although HLA-E displays a selective preference for nonameric peptides derived from the leader sequences of various HLA class I alleles, several reports showed that it can also present "non-canonical" peptides derived from both stress-related and pathogen-associated proteins. Because HLA-E displays binding specificity for innate CD94/NKG2 receptors but also has the features of an antigen-presenting molecule--including the ability to be recognized by ab T cells--it does appear that this MHC class Ib molecule plays an important role in both natural and acquired immune responses.

CD34+ hemopoietic precursor and stem cells traffic in peripheral blood of celiac patients is significantly increased but not directly related to epithelial damage severity

Celiac disease (CD) is a chronic inflammatory enteropathy of the small bowel resulting from a local TH1-mediated reaction to wheat gliadins and barley, rye and oat prolamins with the development of auto-antibodies to transglutaminases. As well as for other chronic inflammatory diseases, genetic background and environmental factors participate to pathogenesis. An increased traffic of CD34+ hemopoietic precursor and stem cells (HPC) has been reported in peripheral blood (PB) of subjects with allergic diseases that share in their pathogenesis immuno-mediated reactions, genetic and environmental factors. The aim of the present work was to investigate the CD34+ cell traffic and H2/H1 polarization of lymphoid T-cell lineage, in the peripheral blood of subjects with CD, by means of flow-cytometric techniques. Group A of control was of 20 healthy subjects, aged 5 to 58 years. Study population (Group B) was of twenty-eight patients, all females aged 13 to 70, receiving firstly a CD diagnosis at the SS Annunziata Hospital Digestive Physiopathology Out-standings' by means of clinical, serologic and small intestinal biopsy findings. Peripheral CD34+ HPCs were significantly increased in Group B (median value 0.16) when compared with Group A (median value 0.03) (p 0.0001) but did not correlate either with anti-transglutaminase (tTG) antibody levels (IgA: p 0.226; IgG: p 0.810) or with histological damage severity (p 0.41) that, on the contrary, was significantly related with anti-tTG IgA antibodies (p 0.027). Celiac circulating CD3+CD4+ lymphocytes expressed a chemokine-receptor pattern Th2-skewed in all but three patients investigated. Concluding, the CD34+ HPC highly increased peripheral traffic observed in celiac disease appears more related to a basic and emerging as common defect shared by chronic inflammatory diseases than to the gliadin-specific Th1 local reactions. Data are consistent with a potential NFkappaB deficiency and consequent prevalence of apoptotic versus survival programs leading to excessive cell-death; to replace lost cells a supplementary bone-marrow derived precursors supply, further to that physiologically provided by the gut stem cell "niches" that are cryptopatches, could be required.

Dendritic cells release HLA-B-associated transcript-3 positive exosomes to regulate natural killer function

NKp30, a natural cytotoxicity receptor expressed on NK cells is critically involved in direct cytotoxicity against various tumor cells and directs both maturation and selective killing of dendritic cells. Recently the intracellular protein BAT3, which is involved in DNA damage induced apoptosis, was identified as a ligand for NKp30. However, the mechanisms underlying the exposure of the intracellular ligand BAT3 to surface NKp30 and its role in NK-DC cross talk remained elusive. Electron microscopy and flow cytometry demonstrate that exosomes released from 293T cells and iDCs express BAT3 on the surface and are recognized by NKp30-Ig. Overexpression and depletion of BAT3 in 293T cells directly correlates with the exosomal expression level and the activation of NK cell-mediated cytokine release. Furthermore, the NKp30-mediated NK/DC cross talk resulting either in iDC killing or maturation was BAT3-dependent. Taken together this puts forward a new model for the activation of NK cells through intracellular signals that are released via exosomes from accessory cells. The manipulation of the exosomal regulation may offer a novel strategy to induce tumor immunity or inhibit autoimmune diseases caused by NK cell-activation.

Natural killer cell activation and modulation of chemokine receptor profile in vitro by an extract from the cyanophyta Aphanizomenon flos-aquae

The present research was designed to study the effects of an extract from the edible cyanophyta Aphanizomenon flos-aquae on human natural killer (NK) cells. We have previously shown, using a double-blind randomized placebo-controlled crossover design, that ingestion of 1.5 g of dried whole A. flos-aquae resulted in a transient reduction in peripheral blood NK cells in 21 healthy human volunteers, suggesting increased NK cell homing into tissue. We have now identified an extract from A. flos-aquae (AFAe) that directly activates NK cells in vitro and modulates the chemokine receptor profile. NK cell activation was evaluated by expression of CD25 and CD69 on CD3-CD56+ cells after 18 hours. Changes in CXCR3 and CXCR4 chemokine receptor expression after 5-60 minutes were evaluated by immunostaining and flow cytometry. AFAe induced the expression of CD69 on CD3-CD56+ NK cells, induced CD25 expression on 25% of these cells, and acted in synergy with interleukin 2. NK cells enriched by RosetteSep (StemCell Technologies Inc., Vancouver, BC, Canada) were not activated by AFAe, indicating that the NK activation was dependent on other cells such as monocytes. The low-molecular-weight fraction <5,000 of AFAe was responsible for the most robust NK cell activation, suggesting novel compounds different from previously reported macrophage-activating large polysaccharides.

Flow cytometry characterization of leukemic phase of nasal NK/T-cell lymphoma in tumor biopsies and peripheral blood

We report the findings of the immunophenotypic profile of three cases of nasal T/NK cell lymphoma in leukemic phase. Flow cytometry analysis was carried out using cell suspensions of tumor nasal biopsies and peripheral blood. Tumor samples were composed by a mixture of a predominant subset of medium-size true NK cytCD3epsilon-, sCD3epsilon-, CD56+ cells mixed with a minor subset of medium-size T/NK sCD3epsilon+, CD56+ cells. Both subsets were also detected in peripheral blood. In addition, an infiltration of small-size sCD3epsilon+, CD56- normal T lymphocytes was also present.

The conceptus increases secreted phosphoprotein 1 gene expression in the mouse uterus during the progression of decidualization mainly due to its effects on uterine natural killer cells

Within the mouse endometrium, secreted phosphoprotein 1 (SPP1) gene expression is mainly expressed in the luminal epithelium and some macrophages around the onset of implantation. However, during the progression of decidualization, it is expressed mainly in the mesometrial decidua. To date, the precise cell types responsible for the expression in the mesometrial decidua has not been absolutely identified. The goal of the present study was to assess the expression of SPP1 in uteri of pregnant mice (decidua) during the progression of decidualization and compared it with those undergoing artificially induced decidualization (deciduoma). Significantly (P<0.05) greater steady-state levels of SPP1 mRNA were seen in the decidua when compared with deciduoma. Further, in the decidua, the majority of the SPP1 protein was localized within a subpopulation of granulated uterine natural killer (uNK) cells but not co-localized to their granules. However, in addition to being localized to uNK cells, SPP1 protein was also detected in another cell type(s) that were not epidermal growth factor-like containing mucin-like hormone receptor-like sequence 1 protein-positive immune cells that are known to be present in the uterus at this time. Finally, decidual SPP1 expression dramatically decreased in uteri of interleukin-15-deficient mice that lack uNK cells. In conclusion, SPP1 expression is greater in the mouse decidua when compared with the deciduoma after the onset of implantation during the progression of decidualization. Finally, uNK cells were found to be the major source of SPP1 in the pregnant uterus during decidualization. SPP1 might play a key role in uNK killer cell functions in the uterus during decidualization.

A novel multiparametric flow cytometry-based cytotoxicity assay simultaneously immunophenotypes effector cells: comparisons to a 4 h 51Cr-release assay

Natural killer (NK) cell-or T cell-mediated cytotoxicity traditionally is measured in 4-16 h (51)Cr-release assays (CRA). A new four-color flow cytometry-based cytotoxicity assay (FCC) was developed to simultaneously measure NK cell cytotoxicity and NK cell phenotype (CD3(-)CD16(+)CD56(+)). Target cells, K562 or Daudi, were labeled with Cell Tracker Orange (CTO) prior to the addition of effector cells. Following co-incubation, 7 amino-actinomycin D (7-AAD) was added to measure death of target cells. The phenotype of effectors, viability of targets, the formation of tumor-effector cell conjugates and absolute numbers of all cells were measured based on light scatter (FSC/SSC), double discrimination of the fluorescence peak integral and height, and fluorescence intensity. Kinetic studies (0.5 and 1 to 4 h) at different effector to target (E:T) cell ratios (50, 25, 12, and 6) confirmed that the 3 h incubation was optimal. The FCC assay is more sensitive than the CRA, has a coefficient of variation (CV) 8-13% and reliably measures NK cell-or lymphokine-activated killer (LAK) cell-mediated killing of target cells in normal controls and subjects with cancer. The FCC assay can be used to study a range of phenotypic attributes, in addition to lytic activity of various subsets of effector cells, without radioactive tracers and thus, it is relatively inexpensive. The FCC assay has a potential for providing information about molecular interactions underlying target cell lysis and thus becoming a major tool for studies of disease pathogenesis as well as development of novel immune therapies.

The human cytomegalovirus MHC class I homolog UL18 inhibits LIR-1+ but activates LIR-1- NK cells

The inhibitory leukocyte Ig-like receptor 1 (LIR-1, also known as ILT2, CD85j, or LILRB1) was identified by its high affinity for the human CMV (HCMV) MHC class I homolog gpUL18. The role of this LIR-1-gpUL18 interaction in modulating NK recognition during HCMV infection has previously not been clearly defined. In this study, LIR-1(+) NKL cell-mediated cytotoxicity was shown to be inhibited by transduction of targets with a replication-deficient adenovirus vector encoding UL18 (RAd-UL18). Fibroblasts infected with an HCMV UL18 mutant (DeltaUL18) also exhibited enhanced susceptibility to NKL killing relative to cells infected with the parental virus. In additional cytolysis assays, UL18-mediated protection was also evident in the context of adenovirus vector transduction and HCMV infection of autologous fibroblast targets using IFN-alpha-activated NK bulk cultures derived from a donor with a high frequency of LIR-1(+) NK cells. A single LIR-1(high) NK clone derived from this donor was inhibited by UL18, while 3 of 24 clones were activated. CD107 mobilization assays revealed that LIR-1(+) NK cells were consistently inhibited by UL18 in all tested donors, but this effect was often masked in the global response by UL18-mediated activation of a subset of LIR-1(-) NK cells. Although Ab-blocking experiments support UL18 inhibition being induced by a direct interaction with LIR-1, the UL18-mediated activation is LIR-1 independent.

Inhibitory receptor signals suppress ligation-induced recruitment of NKG2D to GM1-rich membrane domains at the human NK cell immune synapse

NKG2D is an activating receptor expressed on all human NK cells and a subset of T cells. In cytolytic conjugates between NK cells and target cells expressing its ligand MHC class I chain-related gene A, NKG2D accumulates at the immunological synapse with GM1-rich microdomains. Furthermore, NKG2D is specifically recruited to detergent-resistant membrane fractions upon ligation. However, in the presence of a strong inhibitory stimulus, NKG2D-mediated cytotoxicity can be intercepted, and recruitment of NKG2D to the immunological synapse and detergent-resistant membrane fractions is blocked. Also, downstream phosphorylation of Vav-1 triggered by NKG2D ligation is circumvented by coengaging inhibitory receptors. Thus, we propose that one way in which inhibitory signaling can control NKG2D-mediated activation is by blocking its recruitment to GM1-rich membrane domains. The accumulation of activating NK cell receptors in GM1-rich microdomains may provide the necessary platform from which stimulatory signals can proceed.

Organelle Proteomics

Natural killer (NK) cells and cytotoxic T lymphocytes eliminate virally infected and transformed cells. Target cell killing is mediated by the regulated exocytosis of secretory lysosomes, which deliver perforin and proapoptotic granzymes to the infected or transformed cell. Yet despite the central role that secretory lysosome exocytosis plays in the immune response to viruses and tumors, little is known about the molecular machinery that regulates the docking and fusion of this organelle with the plasma membrane. To identify potential components of this exocytic machinery we used proteomics to define the protein composition of the NK cell secretory lysosome membrane. Secretory lysosomes were isolated from the NK cell line YTS by subcellular fractionation, integral membrane proteins and membrane-associated proteins were enriched using Triton X-114 and separated by SDS-PAGE, and tryptic peptides were identified by LC ESI-MS/MS. In total 221 proteins were identified unambiguously in the secretory lysosome membrane fraction of which 61% were predicted to be either integral membrane proteins or membrane-associated proteins. A significant proportion of the proteins identified play a role in vesicular trafficking, including members of both the Rab GTPase and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) and protein families. These proteins include Rab27a and the SNARE vesicle-associated membrane protein-7, both of which were enriched in the secretory lysosome fraction and represent potential components of the machinery that regulates the exocytosis of this organelle in NK cells.

High-throughput killer cell immunoglobulin-like receptor genotyping by MALDI-TOF mass spectrometry with discovery of novel alleles

The killer cell immunoglobulin-like receptors (KIR) interact with major histocompatibility complex (MHC) class I ligands to regulate the functions of natural killer cells and T cells. Like human leukocyte antigens class I, human KIR are highly variable and correlated with infection, autoimmunity, pregnancy syndromes, and transplantation outcome. Limiting the scope of KIR analysis is the low resolution, sensitivity, and speed of the established methods of KIR typing. In this study, we describe a first-generation single nucleotide polymorphism (SNP)-based method for typing the 17 human KIR genes and pseudogenes that uses analysis by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. It is a high-throughput method that requires minute amounts of genomic DNA for discrimination of KIR genes with some allelic resolution. A study of 233 individuals shows that the results obtained by the SNP-based KIR/MALDI-TOF method are consistent with those obtained with the established sequence-specific oligonucleotide probe or sequence-specific polymerase chain reaction methods. The added sensitivity of the KIR/MALDI-TOF method allowed putative novel alleles of the KIR2DL1, KIR3DL1, KIR2DS5, and KIR2DL5 genes to be identified. Sequencing the KIR2DL5 variant proved it was a newly discovered allele, one that appears associated with Hispanic and Native American populations. This KIR/MALDI-TOF method of KIR typing should facilitate population and disease-association studies that improve knowledge of the immunological functions of KIR-MHC class I interactions.

NKT Cell Activation Mediates Neutrophil IFN-γ Production and Renal Ischemia-Reperfusion Injury

Previous work has shown that ischemia-reperfusion (IR) injury (IRI) is dependent on CD4(+) T cells from naive mice acting within 24 h. We hypothesize that NKT cells are key participants in the early innate response in IRI. Kidneys from C57BL/6 mice were subjected to IRI (0.5, 1, 3, and 24 h of reperfusion). After 30 min of reperfusion, we observed a significant increase in CD4(+) cells (145% of control) from single-cell kidney suspensions as measured by flow cytometry. A significant fraction of CD4(+) T cells expressed the activation marker, CD69(+), and adhesion molecule, LFA-1(high). Three hours after reperfusion, kidney IFN-gamma-producing cells were comprised largely of GR-1(+)CD11b(+) neutrophils, but also contained CD1d-restricted NKT cells. Kidney IRI in mice administered Abs to block CD1d, or deplete NKT cells or in mice deficient of NKT cells (Jalpha18(-/-)), was markedly attenuated. These effects were associated with a significant decrease in renal infiltration and, in activation of NKT cells, and a decrease in IFN-gamma-producing neutrophils. The results support the essential role of NKT cells and neutrophils in the innate immune response of renal IRI by mediating neutrophil infiltration and production of IFN-gamma.

iTRAQ is a useful method to screen for membrane-bound proteins differentially expressed in human natural killer cell types

We are interested in the biological as well as the molecular processes involved in natural killer (NK) cell development and function. Determining the proteomic complement could be a useful tool in predicting cellular function and fate. For the first time shown here, we have utilized iTRAQ, a new method that allows identification and quantification of proteins between multiple samples, to determine the expression of membrane-bound proteins in two previously characterized human NK cell populations. One population was derived from umbilical cord blood (UCB) stem cells (CD34+38-Lin-) and the other from expanded CD3-depleted adult peripheral blood. iTRAQ was employed for multiplex peptide labeling of proteins from fractionated membranes followed by two-dimensional high-performance liquid chromatography (2D-HPLC), and tandem mass spectrometry was used to identify protein signatures. We were able to identify and quantify differences in expression levels of 400-800 proteins in a typical experiment. Ontology analysis showed the majority of the proteins to be involved in cell signaling, nucleic acid binding, or mitochondrial function. Nearly all proteins were associated with the plasma membrane, membrane-bound organelle (lysosome or mitochondria), or nucleus. We found several novel proteins highly expressed in UCB stem cell derived NK cells compared to adult NK cells including CD9, alpha-2 macroglobulin, brain abundant signaling protein (BASP1), and allograft inflammatory factor-1 (AIF-1). In addition, we were able to confirm several of our iTRAQ results by RT-PCR, Western blot, and fluorescence-activated cell-sorting (FACS) analysis. This is the first demonstration and verification using iTRAQ to screen for membrane-bound protein differences in human NK cells and represents a powerful new tool in the field of proteomics.

Induction of CD16+ CD56bright NK cells with antitumour cytotoxicity not only from CD16- CD56bright NK Cells but also from CD16- CD56dim NK cells

The aim of this study was to examine the effect of cytokines on different subsets of NK cells, while especially focusing on CD16(-) CD56(dim) cells and CD16(-) CD56(bright) cells. When human peripheral blood mononuclear cells (PBMC) were cultured with a combination of IL-2, IL-12 and IL-15 for several days, a minor population of CD56(bright) NK cells expanded up to 15%, and also showed potent cytotoxicities against various cancer cells. Sorting experiments revealed that unconventional CD16(-) CD56(+) NK cells (CD16(-) CD56(dim) NK cells and CD16(-) CD56(bright) NK cells, both of which are less than 1% in PBMC) much more vigorously proliferated after cytokine stimulation, whereas predominant CD16(+) CD56(dim) NK cells proliferated poorly. In addition, many of the resting CD16(-) CD56(bright) NK cells developed into CD16(+) CD56(bright) NK cells, and CD16(-) CD56(dim) NK cells developed into CD16(-) CD56(bright) NK cells and also further into CD16(+) CD56(bright) NK cells by the cytokines. CSFE label experiments further substantiated the proliferation capacity of each subset and the developmental process of CD16(+) CD56(bright) NK cells. Both CD16(-) CD56(dim) NK cells and CD16(-) CD56(bright) NK cells produced large amounts of IFN-gamma and Fas-ligands. The CD16(+) CD56(bright) NK cells showed strong cytotoxicities against not only MHC class I (-) but also MHC class I (+) tumours regardless of their expression of CD94/NKG2A presumably because they expressed NKG2D as well as natural cytotoxicity receptors. The proliferation of CD16(+) CD56(bright) NK cells was also induced when PBMC were stimulated with penicillin-treated Streptococcus pyogenes, thus suggesting their role in tumour immunity and bacterial infections.

Human KIR2DL5 Is an Inhibitory Receptor Expressed on the Surface of NK and T Lymphocyte Subsets

Human NK cells, by means of a repertoire of clonally distributed killer cell Ig-like receptors (KIR), survey the expression of individual self HLA class I molecules, which is often altered in infections and tumors. KIR2DL5 (CD158f) is the last identified KIR gene and, with KIR2DL4, constitutes a structurally divergent lineage conserved in different primate species. Research on KIR2DL5 has thus far been limited to its genetic aspects due to a lack of reagents to detect its product. We report here the identification and characterization of the receptor encoded by KIR2DL5 using a newly generated specific mAb that recognizes its most commonly expressed allele, KIR2DL5A*001. KIR2DL5 displays a variegated distribution on the surface of CD56(dim) NK cells. This contrasts with the expression pattern of its structural homolog KIR2DL4 (ubiquitous transcription, surface expression restricted to CD56(bright) NK cells) and resembles the profile of KIR recognizing classical HLA class I molecules. Like other MHC class I receptors, KIR2DL5 is also found in a variable proportion of T lymphocytes. KIR2DL5 is detected on the cell surface as a monomer of approximately 60 kDa that, upon tyrosine phosphorylation, recruits the Src homology region 2-containing protein tyrosine phosphatase-2 and, to a lesser extent, Src homology region 2-containing protein tyrosine phosphatase-1. Ab-mediated cross-linking of KIR2DL5 inhibits NK cell cytotoxicity against murine FcR+ P815 cells. KIR2DL5 is thus an inhibitory receptor gathering a combination of genetic, structural, and functional features unique among KIR, which suggests that KIR2DL5 plays a specialized role in innate immunity.

The contribution of conformational adjustments and long-range electrostatic forces to the CD2/CD58 interaction

CD2 is a T cell surface molecule that enhances T and natural killer cell function by binding its ligands CD58 (humans) and CD48 (rodents) on antigen-presenting or target cells. Here we show that the CD2/CD58 interaction is enthalpically driven and accompanied by unfavorable entropic changes. Taken together with structural studies, this indicates that binding is accompanied by energetically significant conformational adjustments. Despite having a highly charged binding interface, neither the affinity nor the rate constants of the CD2/CD58 interaction were affected by changes in ionic strength, indicating that long-range electrostatic forces make no net contribution to binding.

Functional polymorphism of the KIR3DL1/S1 receptor on human NK cells

NK cells express both inhibitory and activatory receptors that allow them to recognize target cells through HLA class I Ag expression. KIR3DL1 is a receptor that recognizes the HLA-Bw4 public epitope of HLA-B alleles. We demonstrate that polymorphism within the KIR3DL1 receptor has functional consequences in terms of NK cell recognition of target. Inhibitory alleles of KIR3DL1 differ in their ability to recognize HLA-Bw4 ligand, and a consistent hierarchy of ligand reactivity can be defined. KIR3DS1, which segregates as an allele of KIR3DL1, has a short cytoplasmic tail characteristic of activatory receptors. Because it is very similar to KIR3DL1 in the extracellular domains, it has been assumed that KIR3DS1 will recognize a HLA-Bw4 ligand. In this study, we demonstrate that KIR3DS1 is expressed as a protein at the cell surface of NK cells, where it is recognized by the Z27 Ab. Using this Ab, we found that KIR3DS1 is expressed on a higher percentage of NK cells in KIR3DS1 homozygous compared with heterozygous donors. In contrast to the inhibitory KIR3DL1 allotypes, KIR3DS1 did not recognize HLA-Bw4 on EBV-transformed cell lines.

Sensitivity of NK1.1-negative NKT cells to transgenic BATF defines a role for activator protein-1 in the expansion and maturation of immature NKT cells in the thymus

NKT cells are glycolipid-reactive lymphocytes that express markers and perform functions common to both T lymphocytes and NK cells. Although the genetic events controlling conventional T cell development are well defined, the transcription factors and genetic programs regulating NKT cell development are only beginning to be elucidated. Previously, we described the NKT cell-deficient phenotype of transgenic (Tg) mice constitutively expressing B cell-activating transcription factor (BATF), a basic leucine zipper protein and inhibitor of AP-1. In this study, we show that Tg BATF targets the majority of Valpha14Jalpha281 (Valpha14i(7)) NKT cells, regardless of CD4 expression and Vbeta gene usage. The residual NKT cells in the thymus of BATF-Tg mice are CD44(+), yet are slow to display the NK1.1 marker characteristic of mature cells. As a population, BATF-expressing NKT cells are TCRbeta/CD3epsilon(low), but express normal levels of CD69, suggesting a failure to expand appropriately following selection. Consistent with the sensitivity of NKT cells to BATF-induced changes in AP-1 activity, we detect a full complement of AP-1 basic leucine zipper proteins in wild-type NKT cells isolated from the thymus, spleen, and liver, and show that AP-1 DNA-binding activity and cytokine gene transcription are induced in NKT cells within a few hours of glycolipid Ag exposure. This study is the first to characterize AP-1 activity in NKT cells and implicates the integrity of this transcription factor complex in developmental events essential to the establishment of this unique T cell subset in the thymus.

Adoptive transfer of TRAIL-expressing natural killer cells prevents recurrence of hepatocellular carcinoma after partial hepatectomy

BACKGROUND

Antitumor activity of the liver natural killer (NK) cells reportedly decreases after partial hepatectomy, suggesting that patients with such depressed immune status are susceptible to the recurrence of hepatocellular carcinoma (HCC). We hypothesize that adoptive immunotherapy using activated NK cells can be a novel strategy to improve the depressed immune status in patients with HCC after hepatectomy or partial liver transplantation. In the present study, we have tested this hypothesis by using a mouse model.

METHODS

Intraportal injection of 1-5 x 10(6) Hepa1-6 cells (hepatoma cell line) did not result in liver metastases in untreated B6 mice, but led to the growth of liver metastases after extensive partial hepatectomy. Utilizing this murine HCC metastasis model, we investigated the antitumor activity of both remnant liver and exogenously transferred NK cells.

RESULTS

The anti-HCC activity of liver NK cells significantly decreased after partial hepatectomy. The expression of CD69 and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) on liver NK cells was temporarily downregulated. The adoptive transfer of NK cells, including a TRAIL-expressing fraction, extracted from the liver perfusates of poly I:C-stimulated B6 mice inhibited the growth of liver metastasis in B6 or (B6xBALB/c) F1 (B6CF1) mice that underwent hepatectomy and received intraportal Hepa1-6 injection.

CONCLUSIONS

These findings indicate that adoptive immunotherapy using activated NK cells extracted from normal liver perfusates may be a novel technique for reconstituting the depressed immune status in cases of living donor liver transplantation involving HCC patients, recipients of a partial liver graft.

Links between innate and cognate tumor immunity

Cancer results from a tumor cell intrinsic dysregulation of oncogenes, tumor suppressor and stability genes as well as from the avoidance of immunosurveillance. A complex network of cellular interactions allows one to mount cognate anti-tumor immune responses. Recently, discoveries have been made regarding the links between innate and cognate antitumor immunity eliciting protective T-cell responses. The intricate differentiation pathway, whereby dendritic cells can efficiently mature in the tumor microenvironment, appears crucial for the priming of T cells. Transformed cells might deliver danger signals directly to the dendritic cell. Alternatively, other cell types belonging to the innate immune system can sense transformed cells through a specific set of receptors and then interact with dendritic cells to modulate their activation state. A novel subset of innate effector cells called interferon-producing killer dendritic cells are multitasking chimeras that can recognize and kill transformed cells, and undergo a maturation state of antigen presentation. Also, evidence has been produced suggesting that cell death promoted by conventional chemotherapy or radiotherapy might elicit interactions between the innate and the cognate immune system that result in anti-tumor immune responses.

Targeting of products of genes to tumor sites using adoptively transferred A-NK and T-LAK cells

Despite successes in animals, cytokine gene expression selectively in human tumors is difficult to achieve owing to lack of efficient delivery methods. Since interleukin (IL)-2-activated natural killer (A-NK) and phytohemagglutinin and IL-2 activated killer T (T-LAK) cells, as previously demonstrated, localize and accumulate in murine lung tumor metastases following adoptive transfer, we transduced them to test their ability to deliver products of genes selectively to tumors. Assessments of transduction efficiency in vitro demonstrated that adenoviral transduction consistently resulted in high (>60%) transduction rates and substantial expression of transgenes such as GFP, Red2, luciferase, beta-galactosidase and mIL-12 for at least 4 days. In vivo experiments illustrated that Ad-GFP transduced A-NK and Ad-Red2 (RFP) transduced T-LAK or mIL-12 transduced A-NK cells localized 10-50-fold more or survived significantly better than mock transduced cells, respectively, within lung metastases than in the surrounding normal lung tissue. Most importantly, mIL-12 transduced A-NK cells provided a significantly greater antitumor response than non-transduced A-NK cells. Thus, adoptive transfer of A-NK and T-LAK cells represents an efficient method for targeting products of genes to tumor sites.

Molecular analysis and solution structure from small-angle X-ray scattering of the human natural killer inhibitory receptor IRp60 (CD300a)

Natural killer (NK) cells are lymphocytes of the innate immune system specialized in recognition and killing of certain virus-infected and tumor cells. To carry out this task, NK cells are equipped with a complex array of germ line encoded receptors. These receptors deliver either positive or negative signals, and a delicate balance between these signals governs the NK cell cytolytic activity against the target cell. IRp60 (CD300a) is a human NK inhibitory receptor with an immunoglobulin-like fold. In the present study the IRp60 protein was expressed in Escherichia coli as inclusion bodies and refolded by dilution. The refolded protein was purified to homogeneity, biochemical characterized and the solution structure was investigated using small-angle X-ray scattering (SAXS). The SAXS data revealed that IRp60 is monomeric in solution with a molecular shape characteristic of the immunoglobulin-like structures. A homology model of IRp60 was built and validated experimentally against the SAXS data.