-
[show abstract]
[hide abstract]
ABSTRACT: As discussed in this review, human cytomegalovirus (HCMV) infection in healthy individuals is associated with a variable and persistent increase of NK cells expressing the CD94/NKG2C activating receptor. The expansion of NKG2C(+) NK cells reported in other infectious diseases is systematically associated with HCMV co-infection. The functionally mature NKG2C(bright) NK-cell subset expanding in HCMV(+) individuals displays inhibitory Ig-like receptors (KIR and LILRB1) specific for self HLA class I, and low levels of NKp46 and NKp30 activating receptors. Such reconfiguration of the NK-cell compartment appears particularly marked in immunocompromised patients and in children with symptomatic congenital infection, thus suggesting that its magnitude may be inversely related with the efficiency of the T-cell-mediated response. This effect of HCMV infection is reminiscent of the pattern of response of murine Ly49H(+) NK cells against murine CMV (MCMV), and it has been hypothesized that a cognate interaction of the CD94/NKG2C receptor with HCMV-infected cells may drive the expansion of the corresponding NK-cell subset. Yet, the precise role of NKG2C(+) cells in the control of HCMV infection, the molecular mechanisms underlying the NK-cell compartment redistribution, as well as its putative influence in the response to other pathogens and tumors remain open issues.
European Journal of Immunology 04/2013; · 5.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Human cytomegalovirus (HCMV) has been reported to reshape the NK-cell receptor (NKR) distribution, promoting an expansion of CD94/NKG2C(+) NK and T cells. The role of NK cells in congenital HCMV infection is ill-defined. Here we studied the expression of NKR (i.e. NKG2C, NKG2A, LILRB1, CD161) and the frequency of the NKG2C gene deletion in children with past congenital infection, both symptomatic (n = 15) and asymptomatic (n = 11), including as controls children with postnatal infection (n = 11) and non-infected (n = 20). The expansion of NKG2C(+) NK cells in HCMV-infected individuals appeared particularly marked and was associated with an increased number of LILRB1(+) NK cells in cases with symptomatic congenital infection. Increased numbers of NKG2C(+) , NKG2A(+) and CD161(+) T cells were also associated to HCMV infection. The NKG2C deletion frequency was comparable in children with congenital HCMV infection and controls. Remarkably, the homozygous NKG2C(+/+) genotype appeared associated with increased absolute numbers of NKG2C(+) NK cells. Moreover, HCMV-infected NKG2C(+/+) children displayed higher absolute numbers of NKG2A(+) and total NK cells than NKG2C(+/-) individuals. Our study provides novel insights on the impact of HCMV infection on the homeostasis of the NK-cell compartment in children, revealing a modulatory influence of NKG2C copy number.
European Journal of Immunology 09/2012; · 5.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Polymorphisms of the IL28B gene (encoding interferon-λ3) determine the spontaneous course of hepatitis C virus (HCV) infection and its response to antiviral therapy. We investigated the influence of the IL28B rs12979860 (C>T) polymorphism on the risk of severe HCV recurrence after liver transplantation.
Ninety patients who underwent transplantation because of HCV cirrhosis were retrospectively analyzed; forty-one (45.6%) of them with severe HCV recurrence. Forty-eight of their paired donors were available and were also analyzed. IL28B rs12979860 was genotyped by real-time polymerase chain reaction, and evaluated for association with severe HCV recurrence, along with other variables, by univariate and multivariate analyses.
The risk allele rs12979860-T was more common in transplanted patients (66.7%) than reported in healthy whites, and it was significantly overrepresented among patients with severe HCV recurrence, in comparison with patients without it (82.9% vs. 53.1%, odds ratio [OR]=4.30, etiologic fraction=63.6%; P=0.0028). Furthermore, separate analysis of the recipients' genotypes indicated that the risk of severe HCV recurrence increased with the dose of the T allele (linear trend, P=0.0068). Multiple logistic regression analysis confirmed the contribution of the IL28B genotype to the risk of severe HCV recurrence (OR=4.27; P=0.014), independently of other associated factors. Allele IL28B T in the donor seemed to have an opposite effect than that in the recipient (OR=0.46), but the study was underpowered to demonstrate this unforeseen effect (P=0.1995).
The recipient IL28B rs12979860 genotype has a major influence on the posttransplantation course of HCV infection, being a valuable biomarker for patient care in liver transplantation.
Transplantation 07/2012; 94(3):275-80. · 4.00 Impact Factor
-
Manuela Moraru,
Elisa Cisneros,
Natalia Gómez-Lozano,
Rosario de Pablo,
Francisca Portero,
María Cañizares,
Mercedes Vaquero,
Gastón Roustán,
Isabel Millán,
Miguel López-Botet, Carlos Vilches
[show abstract]
[hide abstract]
ABSTRACT: HSV-1 establishes life-long latency that can result in clinical relapses or in asymptomatic virus shedding. Although virtually all adults have been exposed to HSV-1, the clinical course varies remarkably. Genetic host variability could be related to this clinical diversity. In this study, we analyzed the contribution of gene families in chromosomes 1, 6, 12, and 19, which encode key regulators of the innate and adaptive immunity, in a cohort of 302 individuals. Class I and class II alleles of the HLA system, the copy-number variation of NK cell receptor genes (KIR and NKG2C), the combinations of killer cell Ig-like receptor and their HLA ligands, and CD16A and CD32A allotypes of variable affinity for IgG subclasses were all studied. Although no major susceptibility locus for HSV-1 was identified, our results show that the risk of suffering clinical HSV-1 infection is modified by MHC class I allotypes (B*18, C*15, and the group of alleles encoding A19), the high-affinity receptor/ligand pair KIR2DL2/HLA-C1, and the CD16A-158V/F dimorphism. Conversely, HLA class II and CD32A polymorphisms and NKG2C deletion did not seem to influence the clinical course of herpetic infection. Collectively, these findings support an important role in host defense against herpetic infection for several polymorphic genes implicated in adaptive immunity and in surveillance of its subversion. They confirm the crucial role of cytotoxic cells (CTL and NK) and the contribution of genetic diversity to the clinical course of HSV-1 infection.
The Journal of Immunology 04/2012; 188(9):4412-20. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The killer-cell immunoglobulin-like receptors (KIR), which enable NK cells to detect allogeneic target cells and abnormalities in the expression of self-HLA molecules, are encoded by genes that display extensive copy number variation. These variations in the KIR genotype are relevant for multiple aspects of human health, including therapy of cancer. PCR with sequence-specific primers (SSP) is simplest and most widely used among techniques for studying KIR genotypes. Here, we present a protocol that details the critical steps of a method for KIR genotyping by PCR-SSP.
Methods in molecular biology (Clifton, N.J.) 01/2012; 882:415-30.
-
[show abstract]
[hide abstract]
ABSTRACT: A recently developed anti-KIR2DL5 (CD158f) antibody has demonstrated KIR2DL5 expression on the surface of NK and T lymphocytes, making it the last functional KIR identified in the human genome. KIR2DL5 belongs to an ancestral lineage of KIR with Ig-like domains of the D0-D2 type, of which KIR2DL4, an HLA-G receptor, is the only other human member. Despite KIR2DL4 and KIR2DL5 being encoded by genes with similar domain usage, several KIR2DL5 functions resemble more closely those of KIR recognizing classical HLA class I molecules - surface-expressed KIR2DL5 inhibits NK cells through the SHP-2 phosphatase and displays a clonal distribution on NK and T lymphocytes. No activating homolog of KIR2DL5 has been described in any species. The genetics of KIR2DL5 is complicated by duplication of its gene in an ancestor of modern humans living ∼1.7 million years ago. Both KIR2DL5 paralogs have undergone allelic diversification; the centromeric gene is most often represented by alleles whose expression is silenced epigenetically through DNA methylation, thus providing a natural system to investigate the regulation of KIR transcription. The role of KIR2DL5 in immunity is not completely understood, in spite of different attempts to define its ligand. Here we revisit the most relevant characteristics of KIR2DL5, an NK-cell receptor possessing a unique combination of genetic, structural, and functional features.
Frontiers in immunology. 01/2012; 3:289.
-
[show abstract]
[hide abstract]
ABSTRACT: NK cells detect altered patterns of HLA expression in infections and tumors using a variegated repertoire of killer cell Ig-like receptors (KIR). Each clone surveys different HLA molecules by expressing a limited subset of the KIR encoded in its genome, which is maintained throughout cell divisions by epigenetic mechanisms (methylation of the nonexpressed genes). How KIR repertoires are acquired remains, however, unexplained. Human KIR2DL5 is a useful model for studying KIR expression because it has alleles with similar coding regions, but drastically divergent expression - whilst some are transcribed in a typically clonal manner, others, with distinctive promoter polymorphisms, are nonexpressed. Here we investigate the relationship between the sequence diversity of KIR2DL5, including three novel alleles, and its variable transcription. The promoters of the transcribed alleles recruit the transcriptional regulator RUNX3, whilst a mutation shared by all silent alleles precludes this binding. However, all promoters are functional in vitro, and pharmacological DNA demethylation of NK cells rescues the transcription of silent alleles, indicating that only epigenetic mechanisms prevent their inclusion in a normal KIR repertoire. Our results are consistent with a model in which RUNX factors could function as switch elements in the acquisition of KIR repertoires by NK cell precursors.
European Journal of Immunology 08/2007; 37(7):1954-65. · 5.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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 Journal of Immunology 05/2007; 178(7):4402-10. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although natural killer cells lyse targets without pre-sensitization, and in an MHC-unrestricted manner, they can also respond to healthy allogeneic cells of different MHC type. Such alloreactivity is a consequence of NK cells using clonally distributed, inhibitory MHC class I receptors to achieve tolerance to healthy autologous cells. Absence of an appropriate MHC class I ligand on an allogeneic cell erroneously informs the NK cell that the allogeneic cell has lost MHC class I expression and should be killed. Potential NK-cell allo-reactivities are common in non-HLA-identical hematopoietic cell transplants and can have both beneficial and detrimental effects. Less is known of NK-cell allo-reactivities in solid organ transplantation. In animal models NK cells are neither necessary nor sufficient for acute transplant rejection, but they can make a contribution by helping activate T cells. Genes encoding NK-cell receptors for polymorphic MHC class I molecules are also highly polymorphic, contributing to variability of the NK-cell repertoire and response in the human population. These receptors could represent intrinsic patient factors that influence the success of their transplanted solid organs.
Transplant Immunology 01/2007; 17(1):27-30. · 1.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We present here the complete coding sequences, previously unavailable, of the DRB1 alleles DRB1*030102, *0306, *040701, *0408, *1327, *1356, *1411, *1446, *1503, *1504, *0806, *0813, and *0818. For cDNA isolation, new group-specific primers located at the 5'UT and 3'UT regions were used to carry out allele-specific amplification and a convenient method for determining full-length sequences for DRB1 alleles. Complete coding sequencing of samples previously typed as DRB1*0406, DRB1*080101, and DRB1*1111 revealed new alleles with noncoding nucleotide changes at exons 1 and 3. In addition, we found a novel allele, DRB1*0113, whose second exon carries a sequence motif characteristic of DRB1*07 alleles. The predicted class II haplotypic associations of all alleles are reported and discussed.
Human Immunology 01/2007; 67(12):1008-16. · 2.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The generation of killer cell Ig-like receptor (KIR) expression patterns in NK cells involves variegated silencing of KIR genes by DNA methylation. To identify regulatory elements involved in KIR gene activation, upstream regions of KIR genes were functionally characterized in NK3.3 cells as well as in primary NK cells. Three kinds of KIR promoters were defined, controlling clonally expressed KIR genes, the constitutively active KIR2DL4, and the weakly expressed KIR3DL3. Upstream of a short core promoter common to all KIR genes, a region containing functionally divergent elements was characterized. Although this region had no impact on the activity of the KIR2DL3 promoter, an inhibitory element was identified in the KIR2DL4 promoter and an activating element was found in the KIR3DL3 promoter. Upon treatment with a methyltransferase inhibitor, KIR3DL3 expression could be readily induced showing that the low levels of KIR3DL3 expression in peripheral blood are due to sustained DNA methylation of an otherwise fully functional promoter. Analysis of transcription factor binding sites identified a functional acute myeloid leukemia (AML) site common to all three KIR promoters. Mutation of this site led to a substantial increase in activity of all KIR promoters. Among the different members of the AML family, AML-2 was identified as the predominant KIR binding factor. The present study suggests that AML-2 acts as a repressor of KIR expression in mature NK cells and opens the possibility that AML factors and associated cofactors are involved in regulation of KIR expression during NK cell development.
The Journal of Immunology 05/2005; 174(7):4135-43. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Killer-cell Ig-like receptors (KIR) are structurally and functionally diverse, and enable human NK cells to survey the expression of individual HLA class I molecules, often altered in infections and tumors. Multiple events of non-reciprocal recombination have contributed to the rapid diversification of KIR. We show that approximately 4.5% of the individuals of a Caucasoid population bear a recombinant allele of KIR3DP1, officially designed KIR3DP1*004, that associates tightly with gene duplications of KIR3DP1, KIR2DL4 and KIR3DL1/KIR3DS1. The KIR3DP1 gene is normally silent, but the recombinant allele carries a novel promoter sequence and, as a consequence, is transcribed in all tested individuals. Messenger RNA of KIR3DP1*004 is made up of six exons; of these, exons 1-5 are similar to, and spliced like, those encoding the leader peptide and Ig-domains of KIR3D. By contrast, exon 6 is homologous to no other human KIR sequence, but only to possible homologs in chimpanzees and rhesus macaques, and encodes a short hydrophilic tail. The putative KIR3DP1*004 product, like those of the related genes LAIR-2 and LILRA3/ILT6/LIR4, is predicted to be secreted to the extracellular medium rather than anchored to the cell membrane.
European Journal of Immunology 02/2005; 35(1):16-24. · 5.10 Impact Factor
-
European Journal of Immunology - EUR J IMMUNOL. 01/2005; 35(1):16-24.
-
[show abstract]
[hide abstract]
ABSTRACT: Expression of the activating CD94/NKG2C killer lectin-like receptor (KLR) specific for HLA-E was analyzed in peripheral blood lymphocytes (PBLs) from healthy adult blood donors; the expression of other natural killer (NK) cell receptors (ie, CD94/NKG2A, KIR, CD85j, CD161, NKp46, NKp30, and NKG2D) was also studied. Human cytomegalovirus (HCMV) infection as well as the HLA-E and killer immunoglobulin-like receptor (KIR) genotypes were considered as potentially relevant variables associated with CD94/NKG2C expression. The proportion of NKG2C(+) lymphocytes varied within a wide range (<0.1% to 22.1%), and a significant correlation (r = 0.83; P < .001) between NKG2C(+) NK and T cells was noticed. The HLA-E genotype and the number of activating KIR genes of the donors were not significantly related to the percentage of NKG2C(+) lymphocytes. By contrast, a positive serology for HCMV, but not for other herpesviruses (ie, Epstein-Barr and herpes simplex), turned out to be strongly associated (P < .001) with increased proportions of NKG2C(+) NK and T cells. Remarkably, the CD94/NKG2C(+) population expressed lower levels of natural cytotoxicity receptors (NCRs) (ie, NKp30, NKp46) and included higher proportions of KIR(+) and CD85j(+) cells than CD94/NKG2A(+) cells. Altogether, these data support that HCMV infection selectively shapes the natural killer cell receptor (NKR) repertoire of NK and T cells from healthy carrier individuals.
Blood 12/2004; 104(12):3664-71. · 9.90 Impact Factor
-
Steven G E Marsh,
Peter Parham,
Bo Dupont,
Daniel E Geraghty,
John Trowsdale,
Derek Middleton, Carlos Vilches,
Mary Carrington,
Campbell Witt,
Lisbeth A Guethlein,
Heather Shilling,
Christian A Garcia,
Katharine C Hsu,
Hester Wain
Immunogenetics 08/2003; 55(4):220-6. · 2.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A central issue of reproductive immunology in mammals is why a semi-allogeneic embryo is not rejected by the pregnant mother. This is particularly intriguing since, in different species, the early pregnant uterus is infiltrated by numerous maternal lymphocytes, predominantly NK cells. The human NK cell receptor KIR2DL4 has been implicated in the maternal tolerance to the embryo due to its recognition of HLA-G, a non-classical MHC molecule expressed preferentially in the placenta. Killer cell Ig-like receptors (KIR) are believed to participate in the natural immunity to infection and tumors, but KIR2DL4 has unique structural, functional and genetic features that could confer it a different role. However, we demonstrate here that the KIR2DL4:HLA-G interaction is not essential for human reproduction by showing that a multiparous woman lacks a KIR2DL4 gene.
European Journal of Immunology 04/2003; 33(3):639-44. · 5.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Killer-cell immunoglobulin-like receptors (KIR) comprise a family of structurally diverse proteins encoded by a compact cluster of genes located in human Chromosome 19q13.4. The most recently described member of the KIR family, KIR2DL5, is represented in human populations by at least four gene variants, whose exons differ by two to eight nucleotides. We show here that these structurally similar variants are encoded by alleles of two different loci, KIR2DL5A and KIR2DL5B, which map to different regions of the KIR-gene cluster. Regarding KIR2DL5, four groups of KIR haplotypes can be distinguished: those having both KIR2DL5A and KIR2DL5B, those having either KIR2DL5A or KIR2DL5B, and those lacking KIR2DL5. Positive association between KIR2DL5A and KIR2DL5B was detected but did not reach statistical significance. These results are consistent with a model in which KIR2DL5A and KIR2DL5B are products of a gene duplication, which through the action of subsequent recombination have became separated on some haplotypes.
Immunogenetics 09/2002; 54(5):314-9. · 2.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Killer-cell Immunoglobulin-like Receptors (KIR) help human natural killer (NK) cells counteract infections by pathogens that evade the immune system by inducing down-regulation of HLA class I molecules in infected cells. KIRs are structural and functionally diverse receptors encoded by a family of polymorphic genes. The most extreme aspect of KIR polymorphism is the varying content of KIR-genes in the genome of different individuals, as first demonstrated by KIR genotyping using the PCR-SSP method. Knowledge on the KIR-gene family has been recently expanded by the identification of new genes, pseudogenes and multiple gene variants, several of which escaped detection by the original genotyping technique. We present here an upgraded PCR-SSP method for KIR genotyping that integrates recent achievements in the research of the diversity of this gene family. Our method permits detection of all known KIR genes and pseudogenes in a 16-reaction set. Furthermore, an additional set of six reactions permits subtyping of KIR2DL5 variants, each of which shows well-differentiated functional and genetic features.
Tissue Antigens 04/2002; 59(3):184-93. · 2.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The novel HLA-B*3704 allele was identified by polymerase chain reaction with sequence specific oligoneucletides (PCR-SSO) in a Spanish Caucasoid individual whose T-lymphocytes showed an ambiguous HLA-B phenotype. The nucleotide sequence of B*3704 was determined after reverse transcription-polymerase chain reaction (RT-PCR) amplification and molecular cloning of its complete coding region. B*3704 differs from B*3701 by a single nucleotide replacement that induces the substitution of histidine for tyrosine 171. Residue 171 is located in the alpha-helix of the alpha-2 domain, lining the A pocket of the peptide-binding site. Therefore, the His171 substitution seen in HLA-B*3704 is likely to affect its antigen-presenting properties and is probably responsible for the differentiated serological phenotype of this allele in comparison with B*3701.
Tissue Antigens 03/2002; 59(2):142-4. · 2.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: KIR genes have evolved in primates to generate a diverse family of receptors with unique structures that enable them to recognize MHC-class I molecules with locus and allele-specificity. Their combinatorial expression creates a repertoire of NK cells that surveys the expression of almost every MHC molecule independently, thus antagonizing the spread of pathogens and tumors that subvert innate and adaptive defense by selectively downregulating certain MHC class I molecules. The genes encoding KIR that recognize classical MHC molecules have diversified rapidly in human and primates; this contrasts with conservation of immunoglobulin- and lectin-like receptors for nonclassical MHC molecules. As a result of the variable KIR-gene content in the genome and the polymorphism of the HLA system, dissimilar numbers and qualities of KIR:HLA pairs function in different humans. This diversity likely contributes variability to the function of NK cells and T-lymphocytes by modulating innate and adaptive immune responses to specific challenges.
Annual Review of Immunology 02/2002; 20:217-51. · 52.76 Impact Factor
