Expression profile of KIR3DS1/KIR3DL1 receptors in association with immunological responses in TB, HIV and HIV/TB infected patients.

Several studies investigated KIR3DS1 and KIR3DL1 in the context of various infections. However, none of the studies were performed on KIR3DS1/L1 in association with IFN-É£/IL-10 in TB, HIV-1, and their confections. We aimed to evaluate KIR3DS1/KIR3DL1 expression in association with IFNÉ£/IL-10 in HIV-1 and TB mono-infections and HIV-1/TB confection and compared with uninfected controls using RTq PCR. We also performed correlation analysis between KIR3DS1, KIR3DL1, IFN-É£ and IL-10 in the respective cohorts. The overall expression of KIR3DS1 was found to be downregulated in all groups, whereas in HIV-1 and HIV-1/TB, the frequency of KIR3DS1(+) expression was significantly (p < 0.05) associated with undetected HIV-1 viral load. However, expression of KIR3DL1 was found to be significantly (p < 0.05) upregulated in HIV-1 only. In addition, IFNÉ£ expression was significantly (p < 0.05) decreased in TB, whereas in HIV-1/TB, IFNÉ£ expression was significantly (p < 0.05) increased. In contrast, IL-10 expression was significantly (p < 0.05) increased in HIV-1 and HIV-1/TB but not in TB. Also, we found significant positive correlation (p < 0.05, r = 0.61) between KIR3DL1 and IFNÉ£ expression in TB and negative correlation (p < 0.05, r = - 0.62) between KIR3DS1 and IL-10 in HIV-1/TB. In conclusion, we suggest that expression of KIR3DS1/L1 is associated with IFNÉ£/IL-10 responses and it is involved in modulating disease severity in HIV-1 and TB infections.

Killer cell immunoglobulin-like receptor three domains long cytoplasmic tail 1 gene *007 may modulate disease progression of human immunodeficiency virus-1 infection in the Japanese population.

One of the KIR allele, KIR3DL1*007, was associated with the progression to acquired immunodeficiency syndrome and not with the susceptibility to HIV-1 infection in the Japanese and Indian populations, implying that KIR3DL1*007-positive NK cells might eliminate HIV-infected cells less effectively than NK cells bearing the other KIR3DL1 alleles or KIR3DS1 alleles.

Allele imputation for the killer cell immunoglobulin-like receptor KIR3DL1/S1.

Highly polymorphic interaction of KIR3DL1 and KIR3DS1 with HLA class I ligands modulates the effector functions of natural killer (NK) cells and some T cells. This genetically determined diversity affects severity of infections, immune-mediated diseases, and some cancers, and impacts the course of immunotherapies, including transplantation. KIR3DL1 is an inhibitory receptor, and KIR3DS1 is an activating receptor encoded by the KIR3DL1/S1 gene that has more than 200 diverse and divergent alleles. Determination of KIR3DL1/S1 genotypes for medical application is hampered by complex sequence and structural variation, requiring targeted approaches to generate and analyze high-resolution allele data. To overcome these obstacles, we developed and optimized a model for imputing KIR3DL1/S1 alleles at high-resolution from whole-genome SNP data. We designed the model to represent a substantial component of human genetic diversity. Our Global imputation model is effective at genotyping KIR3DL1/S1 alleles with an accuracy ranging from 88% in Africans to 97% in East Asians, with mean specificity of 99% and sensitivity of 95% for alleles >1% frequency. We used the established algorithm of the HIBAG program, in a modification named Pulling Out Natural killer cell Genomics (PONG). Because HIBAG was designed to impute HLA alleles also from whole-genome SNP data, PONG allows combinatorial diversity of KIR3DL1/S1 with HLA-A and -B to be analyzed using complementary techniques on a single data source. The use of PONG thus negates the need for targeted sequencing data in very large-scale association studies where such methods might not be tractable.

A Genome-Wide CRISPR/Cas9-Based Screen Identifies Heparan Sulfate Proteoglycans as Ligands of Killer-Cell Immunoglobulin-Like Receptors.

While human leukocyte antigen (HLA) and HLA-like proteins comprise an overwhelming majority of known ligands for NK-cell receptors, the interactions of NK-cell receptors with non-conventional ligands, particularly carbohydrate antigens, is less well described. We previously found through a bead-based HLA screen that KIR3DS1, a formerly orphan member of the killer-cell immunoglobulin-like receptor (KIR) family, binds to HLA-F. In this study, we assessed the ligand binding profile of KIR3DS1 to cell lines using Fc fusion constructs, and discovered that KIR3DS1-Fc exhibited binding to several human cell lines including ones devoid of HLA. To identify these non-HLA ligands, we developed a magnetic enrichment-based genome-wide CRISPR/Cas9 knock-out screen approach, and identified enzymes involved in the biosynthesis of heparan sulfate as crucial for the binding of KIR3DS1-Fc to K562 cells. This interaction between KIR3DS1 and heparan sulfate was confirmed via surface plasmon resonance, and removal of heparan sulfate proteoglycans from cell surfaces abolished KIR3DS1-Fc binding. Testing of additional KIR-Fc constructs demonstrated that KIR family members containing a D0 domain (KIR3DS1, KIR3DL1, KIR3DL2, KIR2DL4, and KIR2DL5) bound to heparan sulfate, while those without a D0 domain (KIR2DL1, KIR2DL2, KIR2DL3, and KIR2DS4) did not. Overall, this study demonstrates the use of a genome-wide CRISPR/Cas9 knock-out strategy to unbiasedly identify unconventional ligands of NK-cell receptors. Furthermore, we uncover a previously underrecognized binding of various activating and inhibitory KIRs to heparan sulfate proteoglycans that may play a role in NK-cell receptor signaling and target-cell recognition.

KIR3DS1 directs NK cell-mediated protection against human adenovirus infections.

Human adenoviruses (HAdVs) are a major cause for disease in children, in particular after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Currently, effective therapies for HAdV infections in immunocompromised hosts are lacking. To decipher immune recognition of HAdV infection and determine new targets for immune-mediated control, we used an HAdV infection 3D organoid system, based on primary human intestinal epithelial cells. HLA-F, the functional ligand for the activating NK cell receptor KIR3DS1, was strongly up-regulated and enabled enhanced killing of HAdV5-infected cells in organoids by KIR3DS1+ NK cells. In contrast, HLA-A and HLA-B were significantly down-regulated in HAdV5-infected organoids in response to adenoviral E3/glycoprotein19K, consistent with evasion from CD8+ T cells. Immunogenetic analyses in a pediatric allo-HSCT cohort showed a reduced risk to develop severe HAdV disease and faster clearance of HAdV viremia in children receiving KIR3DS1+/HLA-Bw4+ donor cells compared with children receiving non­KIR3DS1+/HLA-Bw4+ cells. These findings identify the KIR3DS1/HLA-F axis as a new target for immunotherapeutic strategies against severe HAdV disease.

Dynamic mRNA expression of donor-derived activating KIR genes and their significant effects on clinical outcome after haematopoietic stem cell transplantation.

Numerous reports suggest that activating killer immunoglobulin-like receptors (aKIRs) of natural killer (NK) cells, in addition to inhibitory KIRs (iKIRs), play a prognostic role after allogeneic haematopoietic stem cell transplantation (allo-HSCT). We aimed to investigate the association between the dynamic expression of KIRs on NK cells and the outcomes, particularly regarding graft-versus-host disease (GvHD). This study retrospectively enrolled 260 pairs of donors and recipients who had undergone allo-HSCT without in-vitro T cell depletion. The mRNA transcription level of KIRs was determined by quantitative real-time polymerase chain reaction (RT-qPCR). The levels of aKIR transcripts were decreased more than those of iKIRs during the occurrence of GvHD. The transcription levels of KIR2DS2 and KIR2DS4 in the patients developing GvHD, compared with those who were at a tolerance state, showed the most significant decrease in the month at their peak transcription levels (p = 0.03, p = 0.002). Significantly decreased expression of KIR2DS1 (p = 0.02), KIR2DS3 (p = 0.04) and KIR2DS5 (p = 0.04) in the GvHD group was observed when the transcription level reached a maximum. High expression of KIR3DS1 was associated with superior overall survival (OS) (p < 0.001). The expression of KIR2DS4 in the KIR genotype Bx group decreased more during GvHD, particularly at 3M (p = 0.02). These findings suggest that KIR genes are potential post-HSCT biomarkers and dynamic changes in the KIR transcription levels can be detected to better predict the occurrence and evaluate the treatment of GvHD after transplantation.

Upregulation of HLA-F expression by BK polyomavirus infection induces immune recognition by KIR3DS1-positive natural killer cells.

BK polyomavirus-associated nephropathy is a common complication after kidney transplantation leading to reduced graft function or loss. The molecular pathogenesis of BK polyomavirus-induced nephropathy is not well understood. A recent study had described a protective effect of the activating natural killer cell receptor KIR3DS1 in BK polyomavirus-associated nephropathy, suggesting a role of NK cells in modulating disease progression. Using an in vitro cell culture model of human BK polyomavirus infection and kidney biopsy samples from patients with BK polyomavirus-associated nephropathy, we observed significantly increased surface expression of the ligand for KIR3DS1, HLA-F, on BK polyomavirus-infected kidney tubular cells. Upregulation of HLA-F expression resulted in significantly increased binding of KIR3DS1 to BK polyomavirus-infected cells and activation of primary KIR3DS-positive natural killer cells. Thus, our data provide a mechanism by which KIR3DS-positive natural killer cells can control BK polyomavirus infection of the kidney, and rationale for exploring HLA-F/KIR3DS1 interactions for immunotherapeutic approaches in BK polyomavirus-associated nephropathy.

The Loss of HLA-F/KIR3DS1 Ligation Is Mediated by Hemoglobin Peptides.

The human leukocyte antigen (HLA)-Ib molecule, HLA-F, is known as a CD4+ T-cell protein and mediator of HIV progression. While HLA-Ia molecules do not have the chance to select and present viral peptides for immune recognition due to protein downregulation, HLA-F is upregulated. Post HIV infection, HLA-F loses the affinity to its activating receptor KIR3DS1 on NK cells leading to progression of the HIV infection. Several studies aimed to solve the question of the biophysical interface between HLA ligands and their cognate receptors. It became clear that even an invariant HLA molecule can be structurally modified by the variability of the bound peptide. We recently discovered the ability of HLA-F to select and present peptides and the HLA-F allele-specific peptide selection from the proteomic content using soluble HLA (sHLA) technology and a sophisticated MS method. We established recombinant K562 cells that express membrane-bound HLA-F*01:01, 01:03 or 01:04 complexes. While a recombinant soluble form of KIR3DS1 did not bind to the peptide-HLA-F complexes, acid elution of the peptides resulted in the presentation of HLA-F open conformers, and the binding of the soluble KIR3DS1 receptor increased. We used CD4+/HIV- and CD4+/HIV+ cells and performed an MS proteome analysis. We could detect hemoglobin as significantly upregulated in CD4+ T-cells post HIV infection. The expression of cellular hemoglobin in nonerythroid cells has been described, yet HLA-Ib presentation of hemoglobin-derived peptides is novel. Peptide sequence analysis from HLA-F allelic variants featured hemoglobin peptides as dominant and shared. The reciprocal experiment of binding hemoglobin peptide fractions to the HLA-F open conformers resulted in significantly diminished receptor recognition. These results underpin the molecular involvement of HLA-F and its designated peptide ligand in HIV immune escape.

Association of killer-cell immunoglobulin-like receptor genes with acute myelogenous leukaemia.

Killer-cell immunoglobulin-like receptors (KIRs) are important because of their key roles in NK cell development and function. Some KIR genes have been associated with the incidence of haematological malignancies. This study was designed to determine whether the inheritance of specific KIR genes is associated with susceptibility to acute myelogenous leukaemia (AML) in Persians living in south-western Iran. KIR genes and KIR2DS4 variants were typed by polymerase chain reaction-sequence-specific primer (PCR-SSP) in 167 patients with AML and 169 healthy controls. Our results showed 10% of patients-mostly females-were classified as M3. Flt3 mutations were detected in 26% of patients, most of whom had internal tandem duplication (ITD). The frequency of activating KIRs (aKIRs)-mainly KIR3DS1-was higher in patients, whereas inhibitory KIRs (iKIRs)-particularly KIR3DL1 and KIR2DL1-were more common among controls. The incidence of the KIR2DS4fl allele was higher among patients with non-M3 AML than controls. We also found a higher frequency of 4 or more iKIR genes in the controls and a higher frequency of 4 or more aKIR genes in the patients. Individuals with more iKIR than aKIR belonged predominantly to the control group. Individuals with the telomeric AA genotype who had inherited the KIR2DS4fl allele were more frequent in the patient group. According to our results, increased frequency of aKIRs in patients with AML may lead to the hyperactivation of NK cells against malignant cells with reduced or lack of HLA class I molecules followed by NK cell exhaustion which allow malignant cells to progress.

Diversity of KIR/HLA Genotypes and Their Association with Psoriasis Vulgaris in the Western Mexican Population.

NK and some T cell functions are regulated by the interaction between KIR and HLA molecules. Several studies have shown an association between activating KIR genes and the development of autoimmune diseases, including psoriasis vulgaris (PsV). Our objective was to determine the association between KIR/HLA genes and genotypes with PsV in the Western mestizo Mexican population. One hundred subjects diagnosed with PsV (SP) and 108 healthy subjects (HS) were genotyped for 14 KIR genes, HLA-Bw4, HLA-C1, and HLA-C2 by PCR-single specific primer (SSP). Positive associations of the KIR3DS1 gene (odds ratio (OR) 1.959, p = 0.021), G11 genotype (OR 19.940, p = 0.008), and KIR3DS1/HLA-ABw4 (OR 2.265, p = 0.009) were found with susceptibility to PsV. In contrast, the G1 genotype (OR 0.448, p = 0.031) and KIR3DL1/HLA-Bw4Ile80 (OR 0.522, p = 0.022) were negatively associated with susceptibility to this disease. These results suggest an implication of the KIR3DS1/HLA-ABw4 genotype in PsV pathology.

Activating killer cell immunoglobulin-like receptors: Detection, function and therapeutic use.

Killer cell immunoglobulin-like receptors (KIRs) have a central role in the control of natural killer (NK) cell function. The functions of the activating KIRs, as compared to those of the inhibitory KIR, have been more difficult to define due to difficulties in antibody-mediated identification and their apparent low affinities for HLA class I. Immunogenetic studies have shown associations of activating KIRs with the outcome of autoimmune diseases, pregnancy-associated disorders, infectious diseases and cancers. Activating KIR are thus thought to have important roles in the control of natural killer cell functions and their role in disease. In this review, we discuss current knowledge on activating KIR, their ligands and, their roles in the pathogenesis and potential therapy of human diseases.

HLA-F on Autologous HIV-Infected Cells Activates Primary NK Cells Expressing the Activating Killer Immunoglobulin-Like Receptor KIR3DS1.

HIV-exposed seronegative KIR3DS1 homozygotes have a reduced risk of HIV infection. HLA-F is the ligand for the activating NK cell receptor (NKR) KIR3DS1. HLA-F is expressed on HIV-infected CD4 T cells. Coculture of sorted, HIV-infected CD4- (siCD4-) T cells with NK cells activated a higher frequency of KIR3DS1+ than KIR3DS1- NK cells from KIR3DS1 homozygotes to elicit anti-HIV functions such as CCL4, gamma interferon (IFN-γ), and CD107a expression. This was the case whether KIR3DS1+/- NK cells were analyzed inclusively or exclusively by gating out NK cells coexpressing the NKRs, KIR2DL1/L2/L3, 3DL2, KIR2DS1/S2/S3/S5, NKG2A, and ILT2. Blocking the interaction of HLA-F on siCD4- cells with KIR3DS1 on exclusively gated KIR3DS1+ NK cells with KIR3DS1-Fc chimeric protein or an HLA-F-specific monoclonal antibody reduced the frequency of activated KIR3DS1+ cells compared to that under control conditions. KIR3DS1+ NK cell activation by HIV-infected CD4+ cells may underlie the reduced risk of KIR3DS1 homozygotes to HIV infection.IMPORTANCE This study investigated a mechanism that may underly epidemiological studies showing that carriage of the KIR3DS1 homozygous genotype is more frequent among HIV-exposed seronegative subjects than among HIV-susceptible individuals. Carriage of this genotype is associated with a reduced risk of HIV infection. The protective mechanism involves the interaction of HLA-F on CD4+ cells infected with replication-competent HIV with the activating NK receptor, KIR3DS1. This interaction leads to the activation of KIR3DS1+ NK cells for secretion of cytokines and chemokines with anti-HIV activity. Among these is CCL4, which binds and blocks CCR5, the coreceptor for HIV entry of HIV into new target cells. In the setting of an exposure to HIV, incoming HIV-infected cells expressing HLA-F rapidly activate KIR3DS1+ NK cells to elicit anti-HIV activity. Exclusive gating strategies and blocking experiments support the notion that the HLA-F/KIR3DS1 interaction is sufficient to activate NK cell functions.

The Emerging Roles of Human Leukocyte Antigen-F in Immune Modulation and Viral Infection.

Human leukocyte antigens (HLAs) play various critical roles in both innate and adaptive immunity through processes such as presenting antigens to T cells and serving as ligands for receptors expressed on natural killer (NK) cells. Among the HLA class I family, the clinical significance and biological function of HLA-F have been the least investigated and have remained elusive for a long period of time. Previous studies have revealed that HLA-F expression might be involved in various physiological and pathological processes, such as pregnancy, viral infection, cancer, transplantation, and autoimmune diseases. However, recent data have shown that, akin to other HLA family members, HLA-F molecules can interact with both activating and inhibitory receptors on immune cells, such as NK cells, and can present a diverse panel of peptides. These important findings pave new avenues for investigations regarding the functions of HLA-F as an important immune regulatory molecule. In the present review, we summarize the studies on the role of HLA-F in immune modulation, with a special emphasis placed on the roles of HLA-F and KIR3DS1 interactions in viral infection.

A Variant of a Killer Cell Immunoglobulin-like Receptor Is Associated with Resistance to PD-1 Blockade in Lung Cancer.

PURPOSE: PD-(L)1-blocking antibodies have clinical activity in metastatic non-small cell lung cancer (NSCLC) and mediate durable tumor remissions. However, the majority of patients are resistant to PD-(L)1 blockade. Understanding mechanisms of primary resistance may allow prediction of clinical response and identification of new targetable pathways. EXPERIMENTAL DESIGN: Peripheral blood mononuclear cells were collected from 35 patients with NSCLC receiving nivolumab monotherapy. Cellular changes, cytokine levels, gene expression, and polymorphisms were compared between responders and nonresponders to treatment. Findings were confirmed in additional cohorts of patients with NSCLC receiving immune checkpoint blockade. RESULTS: We identified a genetic variant of a killer cell immunoglobulin-like receptor (KIR) KIR3DS1 that is associated with primary resistance to PD-1 blockade in patients with NSCLC. This association could be confirmed in independent cohorts of patients with NSCLC. In a multivariate analysis of the pooled cohort of 135 patients, the progression-free survival was significantly associated with presence of the KIR3DS1 allele (HR, 1.72; 95% confidence interval, 1.10-2.68; P = 0.017). No relationship was seen in cohorts of patients with NSCLC who did not receive immunotherapy. Cellular assays from patients before and during PD-1 blockade showed that resistance may be due to NK-cell dysfunction. CONCLUSIONS: We identified an association of the KIR3DS1 allelic variant with response to PD-1-targeted immunotherapy in patients with NSCLC. This finding links NK cells with response to PD-1 therapy. Although the findings are interesting, a larger analysis in a randomized trial will be needed to confirm KIRs as predictive markers for response to PD-1-targeted immunotherapy.

Allele diversity of the killer cell immunoglobulin-like receptors KIR3DL1/S1 and the combination with their HLA ligands in Mexican Mestizos from Mexico City.

Killer cell immunoglobulin-like receptors (KIRs), expressed on Natural Killer (NK) cells, activate/inhibit NK cell function through interactions with their HLA-A, B and C ligands. KIR3DL1 is one of the most polymorphic genes and its effect varies depending on the interaction of the specific allotype with its Bw4 ligand. We investigated the allelic diversity of KIR3DL1/S1 using sequence based typing and we typed as well, their Bw4 ligands in Mexican Mestizos of Mexico City. The results showed that this population has a great KIR3DL1 allelic diversity with ∗01502 (19.9%), ∗00101 (13.2%) and ∗00501 (12.8%) being the most common alleles, while KIR3DS1 showed predominance of ∗01301 (86%); these data agree with the diversity found in most populations studied. At least one KIR3DL1-HIGH surface expression allele was present in 67.5% of the subjects. Phylogenetic comparisons between Mestizos and 28 different populations showed that allelic diversity of KIR3DL1/S1 was similar in Mexican Mestizos from Mexico and in Hispanics from USA. Knowledge of KIR and MHC diversity worldwide is fundamental for understanding the impact of KIR and KIR-ligand polymorphism on NK cell effector functions and is relevant in genetic anthropology, disease association and transplantation.

[The favorable effects of KIR3DS1 and Bw4(80Ile) on viral set point and CD4 count decline in HIV-1 patients with acutely infected with HIV-1 infection].

Objective: To investigate whether killer cell immunoglobulin-like receptor 3DS1(KIR3DS1)and Bw4(80Ile) could play a protective role during HIV-1 infection. Methods: KIR3DL1/3DS1 and Bw4, Bw6 were genotyped by SSP-PCR and Bw4 allotypes (Bw4(80Ile) and Bw4(80Thr))were classified via sequencing among 109 individuals acutely infected with HIV-1 in Beijing You'an Hospital between 2006 and 2012. Results: (1)Of the 109 patients, 65, 7, and 37 subjects respectively harbored KIR3DL1/KIR3DL1, KIR3DS1/KIR3DS1, and KIR3DL1/KIR3DS1 genotypes. Their viral set points were determined as 4.35±0.79, 4.24±0.49 and 3.99±0.85 respectively. The viral set point of patients carrying KIR3DL1/KIR3DS1 was significantly lower than the KIR3DL1/KIR3DL1 genotype patients (P=0.032). (2)26, 41, 42 subjects harbored Bw4(80Ile,) Bw4(80Thr,) Bw6/6, respectively. Viral set points of these subjects were respectively 3.89±0.49, 4.20±1.03 and 4.44±0.59.One-way ANOVA indicated that Bw4(80Ile)influenced the levels of viral set point(P=0.027). Moreover, the level of viral set point of the Bw4(80Ile) genotype was significantly lower than the Bw6/6 genotype (P=0.020). These outcomes indicated Bw4(80Ile) was associated with lower levels of viral set point.(3)Viral set point of patients harboring KIR3DS1 and Bw4(80Ile)was 3.26±0.81 and significantly lower than individuals possessing other genotypes (all P<0.05). KIR3DS1 and Bw4(80Ile) conferred an advantage over other genotypes, especially over KIR3DS1 and Bw6/6 (P=0.006), KIR3DL1 and Bw6/6 (P=0.015) and even KIR3DL1 and Bw4(80Ile) (P=0.019 6) in delaying CD4 count decline within 3 years after HIV-1 infection. Conclusions: KIR3DS1 and Bw4(80Ile) are synergistically related to lower viral set point and slowing down the CD4 count decline as Bw4(80Ile) in the presence of KIR3DS1.

Analysis of KIR3DP1 Polymorphism Provides Relevant Information on Centromeric KIR Gene Content.

Four killer cell Ig-like receptor (KIR) genes, collectively referred to as framework genes, characterize almost all KIR haplotypes. In particular, KIR3DL3 and KIR3DL2 mark the ends of the locus, whereas KIR3DP1 and KIR2DL4 are located in the central part. A recombination hot spot, mapped between KIR3DP1 and KIR2DL4, splits the haplotypes into two regions: a centromeric (Cen) region (spanning from KIR3DL3 to KIR3DP1) and a telomeric region (from KIR2DL4 to KIR3DL2), both varying in KIR gene content. In this study, we analyzed KIR3DP1 polymorphism in a cohort of 316 healthy, unrelated individuals. To this aim, we divided KIR3DP1 alleles into two groups by the use of a sequence-specific primer- PCR approach. Our data clearly indicated that KIR3DP1 alleles present on haplotypes carrying Cen-A or Cen-B1 regions differ from those having Cen-B2 motifs. Few donors (∼3%) made exceptions, and they were all, except one, characterized by uncommon haplotypes, including either KIR deletions or KIR duplications. Consequently, as KIR2DL1 is present in Cen-A and Cen-B1 regions but absent in Cen-B2 regions, we demonstrated that KIR3DP1 polymorphism might represent a suitable marker for KIR2DL1 gene copy number analysis. Moreover, because Cen-B1 and Cen-B2 regions are characterized by different KIR3DP1 alleles, we showed that KIR3DP1 polymorphism analysis also provides information to dissect between Cen-B1/Cen-B1 and Cen-B1/Cen-B2 donors. Taken together, our data suggest that the analysis of KIR3DP1 polymorphism should be included in KIR repertoire evaluation.

Killer-cell immunoglobulin-like receptors associated with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) affects the endocrine system and is associated with low-grade inflammation. Natural killer (NK) cells are involved in the defense of the female reproductive tract, folliculogenesis, ovulation and the menstrual cycle. The killer-cell immunoglobulin-like receptors (KIR) on the surface of NK cells modulate the activation and function of these cells after interacting with human leukocyte antigen (HLA) class I ligands. The objective of this study was to evaluate the possible association of the KIR and their HLA ligands with polycystic ovary syndrome. METHODS: Ninety-three patients with PCOS according to the Rotterdam criteria and 104 healthy controls were included in this study. The HLA class I and KIR genotypes were determined using a PCR-SSO technique, rSSO Luminex®. In order to assess whether the distribution of the HLA and KIR genotypes was in Hardy-Weinberg equilibrium, Arlequin 3.1 software was used. The frequency distributions in the two study groups were compared using the chi-squared statistic with Yates´s correction using Open Epi software. RESULTS: The higher frequencies of KIR3DS1-Bw4 (41% vs. 19%, Pc = 0.002; OR = 2.90) and homozygotic KIR2DS4-del (54% vs. 26%, Pc = 0.0002; OR = 3.316) in patients compared with controls suggest they confer susceptibility to PCOS. A lower frequency of KIR2DS4-full was observed in patients (43% vs. 70%, Pc = 0.0004, OR = 0.320). CONCLUSION: KIR and its HLA ligands were associated with the development of PCOS in the studied population.

Interactions Between KIR3DS1 and HLA-F Activate Natural Killer Cells to Control HCV Replication in Cell Culture.

Killer-cell immunoglobulin-like receptors (KIRs) are transmembrane glycoproteins expressed by natural killer (NK) cells. Binding of KIR3DS1 to its recently discovered ligand, HLA-F, activates NK cells and has been associated with resolution of hepatitis C virus (HCV) infection. We investigated the mechanisms by which KIR3DS1 contributes to the antiviral immune response. Using cell culture systems, mice with humanized livers, and primary liver tissue from HCV-infected individuals, we found that the KIR3DS1 ligand HLA-F is up-regulated on HCV-infected cells, and that interactions between KIR3DS1 and HLA-F contribute to NK cell-mediated control of HCV. Strategies to promote interaction between KIR3DS1 and HLA-F might be developed for treatment of infectious diseases and cancer.

HLA-F on HLA-Null 721.221 Cells Activates Primary NK Cells Expressing the Activating Killer Ig-like Receptor KIR3DS1.

NK cells elicit important responses against transformed and virally infected cells. Carriage of the gene encoding the activating killer Ig-like receptor KIR3DS1 is associated with slower time to AIDS and protection from HIV infection. Recently, open conformers of the nonclassical MHC class Ib Ag HLA-F were identified as KIR3DS1 ligands. In this study, we investigated whether the interaction of KIR3DS1 on primary NK cells with HLA-F on the HLA-null cell line 721.221 (221) stimulated KIR3DS1+ NK cells. We used a panel of Abs to detect KIR3DS1+CD56dim NK cells that coexpressed the inhibitory NK cell receptors KIR2DL1/L2/L3, 3DL2, NKG2A, and ILT2; the activating NK cell receptors KIR2DS1/S2/S3/S5; and CCL4, IFN-γ, and CD107a functions. We showed that both untreated and acid-pulsed 221 cells induced a similar frequency of KIR3DS1+ cells to secrete CCL4/IFN-γ and express CD107a with a similar intensity. A higher percentage of KIR3DS1+ than KIR3DS1- NK cells responded to 221 cells when either inclusive or exclusive (i.e., coexpressing none of the other inhibitory NK cell receptors and activating NK cell receptors detected by the Ab panel) gating strategies were employed to identify these NK cell populations. Blocking the interaction of HLA-F on 221 cells with KIR3DS1-Fc chimeric protein or anti-HLA-F Abs on exclusively gated KIR3DS1+ cells reduced the frequency of functional cells compared with that of unblocked conditions for stimulated KIR3DS1+ NK cells. Thus, ligation of KIR3DS1 activates primary NK cells for several antiviral functions.