Natural Killer Cell-Based Immunotherapy in Acute Myeloid Leukemia: Lessons for the Future.

The report by Curti et al. highlightsthe potential of NK cell-based adoptive cellular immunotherapy in oncology,currently boosted by advances in the knowledge on NK cell biology and in their ex-vivo GMP manipulation.Several issues deserve attention to fully achieve the translation of these advances to the clinic

Natural Killer Cell-Based Immunotherapy in Acute Myeloid Leukemia: Lessons for the Future.

The report by Curti et al. highlightsthe potential of NK cell-based adoptive cellular immunotherapy in oncology,currently boosted by advances in the knowledge on NK cell biology and in their ex-vivo GMP manipulation.Several issues deserve attention to fully achieve the translation of these advances to the clinic

Complete genomic characterization of a new KLRC2 allele, NKG2C*03

Data de publicació electrònica: 20-02-2021This work was partially funded by grants SAF2016‐80363‐C2‐1/2‐R from the Spanish Ministerio de Ciencia e Innovación (MCINN, Agencia Estatal de Investigación‐AEI/FEDER, EU), and PCIN‐2015‐191‐C02‐01/02 (FP7‐MINECO ERA‐NET Infect‐ERA program, EU) to C.V. and M.L.B. M.M. is hired by grant GCB15152947MELE from the Asociación Española contra el Cáncer Foundation; J.A. is hired by grant PID2019‐110609RB‐C22/AEI/10.13039/501100011033 (AEI/FEDER, EU) to C.V. Publication costs are defrayed by a nominative grant to support research from Consejería de Sanidad de la Comunidad de Madrid in 2021 to Fundación de Investigación Biomédica Puerta de Hierro

Adaptive NK cell response to human cytomegalovirus: Facts and open issues

Human cytomegalovirus (HCMV) infection exerts broad effects on the immune system. These include the differentiation and persistent expansion of a mature NK cell subset which displays a characteristic phenotypic and functional profile hallmarked by expression of the HLA-E-specific CD94/NKG2C activating receptor. Based on our experience and recent advances in the field, we overview the adaptive features of the NKG2C+ NK cell response, discussing observations and open questions on: (a) the mechanisms and influence of viral and host factors; (b) the existence of other NKG2C- NK cell subsets sharing adaptive features; (c) the development and role of adaptive NKG2C+ NK cells in the response to HCMV in hematopoietic and solid organ transplant patients; (d) their relation with other viral infections, mainly HIV-1; and (e) current perspectives for their use in adoptive immunotherapy of cancer.Research is supported by: Agencia Estatal de Investigación-FEDER (PID2019–110609RB-C21-C22/AEI/10.13039/501100011033); Fundació La Marató de TV3 (201822–10); Ministero dell’Istruzione (MIUR) - FRA 219; Ministero dell’Istruzione (MIUR): FISR2020IP_02937; ISCiii/FEDER (PI19/00328; PI22/00040) and CIBERONC

Haplotype-based analysis of KIR-gene profiles in a south european population-distribution of standard and variant Haplotypes, and identification of novel recombinant structures

Inhibitory Killer-cell Immunoglobulin-like Receptors (KIR) specific for HLA class I molecules enable human natural killer cells to monitor altered antigen presentation in pathogen-infected and tumor cells. KIR genes display extensive copy-number variation and allelic polymorphism. They organize in a series of variable arrangements, designated KIR haplotypes, which derive from duplications of ancestral genes and sequence diversification through point mutation and unequal crossing-over events. Genomic studies have established the organization of multiple KIR haplotypes-many of them are fixed in most human populations, whereas variants of those have less certain distributions. Whilst KIR-gene diversity of many populations and ethnicities has been explored superficially (frequencies of individual genes and presence/absence profiles), less abundant are in-depth analyses of how such diversity emerges from KIR-haplotype structures. We characterize here the genetic diversity of KIR in a sample of 414 Spanish individuals. Using a parsimonious approach, we manage to explain all 38 observed KIR-gene profiles by homo- or heterozygous combinations of six fixed centromeric and telomeric motifs; of six variant gene arrangements characterized previously by us and others; and of two novel haplotypes never detected before in Caucasoids. Associated to the latter haplotypes, we also identified the novel transcribed KIR2DL5B * 0020202 allele, and a chimeric KIR2DS2/KIR2DL3 gene (designated KIR2DL3 * 033) that challenges current criteria for classification and nomenclature of KIR genes and haplotypes.This work was supported by grants SAF2016-80363-C2-1/2-R (Spanish Ministry of Economy and Competitiveness (MINECO)-FEDER, EU), and PCIN-2015-191-C02-02 (FP7-MINECO Infect-ERA program) to CV and ML-B. MM was supported by Fundación Asociación Española Contra el Cáncer (AECC) grant GCB15152947MELE. EC was supported, successively, by grants SAF2010–22153-C03, Fundació La Marató de TV3 121531, and PCIN-2015-191-C02-02. AM was supported by Instituto de Salud Carlos III (ISCIII)/FEDER grant PI19/00328

Human cytomegalovirus antigen presentation by HLA-DR+ NKG2C+ adaptive NK cells specifically activates polyfunctional effector memory CD4+ T lymphocytes

Natural killer (NK) cells play a dual role in the defense against viral pathogens by directly lysing infected cells as well as by regulating anti-viral T cell immunity. Infection by human cytomegalovirus (HCMV) promotes a persistent expansion of NKG2C+ adaptive NK cells which have been shown to display enhanced antibody-dependent responses against infected targets and associated to viral control in transplanted patients. Based on gene expression data showing increased transcription of CIITA and several genes related to the MHC class II pathway in adaptive NK cells, we explored their putative capacity for antigen presentation to CD4+ T cells. Phenotypic analysis confirmed a preferential steady-state expression of HLA-DR by circulating NKG2C+ adaptive NK cells in healthy individuals. Expression of HLA-DR in NKG2C+ adaptive NK cells was variable and unrelated to the expression of activation (i.e., CD69 and CD25) or differentiation (i.e., FcRγ chain, CD57) markers, remaining stable over time at the individual level. Incubation of purified NK cells with HCMV complexed with serum specific antibodies induced an up-regulation of surface HLA-DR concomitant to CD16 loss whereas no changes in CD80/CD86 co-stimulatory ligands were detected. In addition, surface CX3CR1 decreased upon antigen-loading while HLA-DR+ NK cells maintained a CCR7-, CXCR3low homing profile. Remarkably, HCMV-loaded purified NK cells activated autologous CD4+ T cells in an HLA-DR dependent manner. The fraction of T lymphocytes activated by antigen-loaded NK cells was smaller than that stimulated by monocyte-derived dendritic cells, corresponding to CD28-negative effector-memory CD4+ T cells with cytotoxic potential. Antigen presentation by NK cells activated a polyfunctional CD4+ T cell response characterized by degranulation (CD107a) and the secretion of Th1 cytokines (IFNγ and TNFα). Overall, our data discloses the capacity of NKG2C+ adaptive NK cells to process and present HCMV antigens to memory CD4+ cytotoxic T cells, directly regulating their response to the viral infection.The authors are supported by Plan Estatal I+D Retos (SAF2016-80363-C2-1-R/-2-R), Spanish Ministry of Economy and Competitiveness (MINECO, FEDER); EU FP7-MINECO Infect-ERA program (PCIN-2015-191-C02-01/02); Fundación Española contra el Cáncer (GCB15152947MELE); Proyecto Integrado de Excelencia ISCIII (PIE 2015/00008); and Worldwide Cancer Research Foundation (15–1146)

Diversity of NKG2C genotypes in a European population: Conserved and recombinant haplotypes in the coding, promoter, and 3'-untranslated regions

Data de publicació electrònica: 08-07-2022NK cells monitor altered molecular patterns in tumors and infected cells through an ample array of receptors. Two families of evolutionarily distant receptors have converged to enable human NK cells to sense levels of HLA class I ligands, frequently abnormal in altered cells. Whilst different forms of polymorphism are a hallmark of killer-cell immunoglobulin-like receptors and their classic HLA-A, B, and C ligands, genetic diversity of killer-cell lectin-like receptors for the non-classical HLA-E (CD94/NKG2 heterodimers) is less conspicuous and has attracted less attention. A common pattern of diversification in both receptor families is evolution of pairs of inhibitory and activating homologs for a common ligand, the genes encoding activating receptors being more frequently affected by copy number variation (CNV). This is exemplified by the gene encoding the activating NKG2C subunit (KLRC2 or NKG2C), which marks an NK-cell subpopulation that differentiates or expands in response to cytomegalovirus. We have studied NKG2C diversity in 240 South European individuals, using polymerase chain reaction and sequencing methods to assess both gene CNV and single-nucleotide polymorphisms (SNPs) affecting its promoter, coding and 3'-untranslated (3'UT) regions. Sequence analysis revealed eight common SNPs-one in the promoter, two in the coding sequence, and five in the 3'UT region. These SNPs associate strongly with each other, forming three conserved extended haplotypes (frequencies: 0.456, 0.221, and 0.117). Homo- and heterozygous combination of these, together with complete gene deletion (0.175) and additional haplotypes with frequencies lower than 0.015, generate a diversity of NKG2C genotypes of potential immunological importance.This article is dedicated to the memory of Benny P. Shum. We thank Dr. Elvira Ramil, from the DNA sequencing core facility of Instituto de Investigación Sanitaria Puerta de Hierro – Segovia de Arana, for continued support. This work was funded by grant PID2019-110609RB-C22/AEI/10.13039/501100011033 (AEI/FEDER, EU). MM and JA were hired by the latter grant and by GCB15152947MELE from the Asociación Española contra el Cáncer Foundation. Karima Al-Akioui-Sanz was supported sequentially by grant PEJ-2017-AI/BMD-7377, with co-financing by EU Youth Employment Initiative, European Social Fund (91.89%), and Consejería de Educación, Juventud y Deporte de la Comunidad de Madrid; and by grant SAF2016-80363-C2-2-R (AEI/FEDER, EU)

Priming of NK cell anti-viral effector mechanisms by direct recognition of human cytomegalovirus

Natural killer (NK) cells play an important role in the defense against viral infections. Activation of resting NK cells is tightly controlled by the balance of surface inhibitory and activating receptors and aided by cytokines released by accessory cells along the anti-viral response. On the other hand, NK cells express functional pattern recognition receptors (PRRs) whose function has been mostly addressed by the use of synthetic agonists. The present study was undertaken to investigate whether NK cells could directly recognize a complex pathogen such as Human Cytomegalovirus (HCMV). Exposure of primary human NK cells to HCMV (TB40/E strain) induced the expression of CD69, promoted IFNγ secretion, and increased their cytotoxic activity against HCMV-infected autologous monocyte-derived dendritic cells. The divergent response induced by infective and UV-inactivated virions indicated the involvement of different NK cell sensors in the recognition of HCMV. The fact that NK cell activation could be partially prevented by blocking mAb specific for IFNAR and TLR2, together with the induction of IFNβ mRNA, supported the involvement of IFNβ and TLR2 in the response to HCMV. Thus, our data indicate that simultaneous activation of several PRRs leads to the autonomous priming of NK cell effector functions and could be a previously unappreciated mechanism presumably contributing to the control of HCMV infection.This work was supported by grants from Plan Nacional de I + D (SAF2010–22153-C03), and EU SUDOE program (SOE2/P1/E341). Aura Muntasell is supported by Asociación Española Contra el Cáncer (AECC), Andrea Vera is supported by Red HERACLES (Instituto de Salut Carlos III)

Impact of zygosity on bimodal phenotype distributions

Allele number, or zygosity, is a clear determinant of gene expression in diploid cells. However, the relationship between the number of copies of a gene and its expression can be hard to anticipate, especially when the gene in question is embedded in a regulatory circuit that contains feedback. Here, we study this question making use of the natural genetic variability of human populations, which allows us to compare the expression profiles of a receptor protein in natural killer cells among donors infected with human cytomegalovirus with one or two copies of the allele. Crucially, the distribution of gene expression in many of the donors is bimodal, which indicates the presence of a positive feedback loop somewhere in the regulatory environment of the gene. Three separate gene-circuit models differing in the location of the positive feedback loop with respect to the gene can all reproduce the homozygous data. However, when the resulting fitted models are applied to the hemizygous donors, one model (the one with the positive feedback located at the level of gene transcription) is superior in describing the experimentally observed gene-expression profile. In that way, our work shows that zygosity can help us relate the structure and function of gene regulatory network

Development of the adaptive NK cell response to human cytomegalovirus in the context ofaging

Human cytomegalovirus (HCMV) establishes a highly prevalent life-long latent infection. Though generally subclinical, HCMV infection may have severe consequences during fetal development and in immunocompromised individuals. Based on epidemiological studies HCMV(+) serology has been associated with the development of atherosclerosis, immune senescence and an increase mortality rate in elderly people. Such long-term detrimental effects of the viral infection presumably result from an inefficient immune control of the pathogen, depending on the quality and evolution of the individual host-pathogen relationship. Together with antigen-specific T lymphocytes, NK cells play an important role in anti-viral immune defense. HCMV promotes in some individuals the differentiation and persistent steady state expansion of an NK cell subset bearing the CD94/NKG2C activating receptor. The relationship between this adaptive NK cell response to HCMV and aging is overviewed.The team is supported by grants from Plan Estatal I + D Retos (SAF2013-49063-C2-1-R, MINECO-FEDER), Fundació La Marató de TV3 (121531) and REEM (RD12/0032/0016, Instituto de Salud Carlos III). AM is supported by Asociación Espanola ˜ Contra el Cáncer (AECC)