RESUMEN
Therapeutic strategies targeting non-adaptive immune cells are currently in clinical development. γδT cells are a small subtype of T cells (1-10% of total T cells) that mediate their effector function without the necessity of the antigen presenting machinery, and also share functional properties with innate cells. Among the different γδT subtypes, antibodies against Vγ9Vδ2T have reported signs of clinical efficacy in early clinical studies. In this review we describe the biology of this subtype of non-conventional T cells and provide insights into the mechanism of action of novel antibodies that activate these cells. We will focus on antibodies targeting the BTN3A ligand and bi-specific γδT cell engagers. We will review in detail the advantages of these strategies including the potential for overcoming mechanisms of resistance to check point inhibitors, or the much more adequate safety profile compared with agents activating classical T cells. Limitations identified during the first studies in humans and strategies to overcome them will be revised and discussed. Finally, clinical options for future clinical development will be suggested.
Asunto(s)
Receptores de Antígenos de Linfocitos T gamma-delta , Humanos , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Animales , Butirofilinas/inmunología , Activación de Linfocitos/inmunología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Inmunoterapia/métodos , Linfocitos Intraepiteliales/inmunología , Antígenos CDRESUMEN
The nucleotide-binding and oligomerization domain-like receptors (NLRs) NLR family CARD domain-containing protein 5 (NLRC5) and Class II Major Histocompatibility Complex Transactivator (CIITA) are transcriptional regulators of major histocompatibility complex (MHC) class I and class II genes, respectively. MHC molecules are central players in our immune system, allowing the detection of hazardous 'non-self' antigens and, thus, the recognition and elimination of infected or transformed cells from the organism. Recently, CIITA and NLRC5 have emerged as regulators of selected genes of the butyrophilin (BTN) family that interestingly are located in the extended MHC locus. BTNs are transmembrane proteins exhibiting structural similarities to B7 family co-modulatory molecules. The family member BTN2A2, which indeed contributes to the control of T cell activation, was found to be transcriptionally regulated by CIITA. NLRC5 emerged instead as an important regulator of the BTN3A1, BTN3A2, and BTN3A3 genes. Together with BTN2A1, BTN3As regulate non-conventional Vγ9Vδ2 T cell responses triggered by selected metabolites of microbial origin or accumulating in hematologic cancer cells. Even if endogenous metabolites conform to the canonical definition of 'self', metabolically abnormal cells can represent a danger for the organism and should be recognized and controlled by immune system cells. Collectively, new data on the role of NLRC5 in the expression of BTN3As link the mechanisms regulating canonical 'non-self' presentation and those marking cells with abnormal metabolic configurations for immune recognition, an evolutionary parallel that we discuss in this perspective review.
Asunto(s)
Butirofilinas , Péptidos y Proteínas de Señalización Intracelular , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Butirofilinas/metabolismo , Butirofilinas/genética , Butirofilinas/inmunología , Animales , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Transactivadores/genética , Transactivadores/metabolismo , Regulación de la Expresión Génica , Activación de Linfocitos/inmunología , Antígenos CDRESUMEN
Butyrophilin (BTN) molecules are emerging as key regulators of T cell immunity; however, how they trigger cell-mediated responses is poorly understood. Here, the crystal structure of a gamma-delta T cell antigen receptor (γδTCR) in complex with BTN2A1 revealed that BTN2A1 engages the side of the γδTCR, leaving the apical TCR surface bioavailable. We reveal that a second γδTCR ligand co-engages γδTCR via binding to this accessible apical surface in a BTN3A1-dependent manner. BTN2A1 and BTN3A1 also directly interact with each other in cis, and structural analysis revealed formation of W-shaped heteromeric multimers. This BTN2A1-BTN3A1 interaction involved the same epitopes that BTN2A1 and BTN3A1 each use to mediate the γδTCR interaction; indeed, locking BTN2A1 and BTN3A1 together abrogated their interaction with γδTCR, supporting a model wherein the two γδTCR ligand-binding sites depend on accessibility to cryptic BTN epitopes. Our findings reveal a new paradigm in immune activation, whereby γδTCRs sense dual epitopes on BTN complexes.
Asunto(s)
Butirofilinas , Receptores de Antígenos de Linfocitos T gamma-delta , Butirofilinas/metabolismo , Butirofilinas/inmunología , Butirofilinas/química , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Humanos , Unión Proteica , Multimerización de Proteína , Antígenos CD/metabolismo , Antígenos CD/inmunología , Antígenos CD/química , Linfocitos T/inmunología , Linfocitos T/metabolismo , Cristalografía por Rayos X , Activación de Linfocitos/inmunología , Modelos Moleculares , Linfocitos Intraepiteliales/inmunología , Linfocitos Intraepiteliales/metabolismoRESUMEN
Butyrophilin (BTN) proteins are a type of membrane protein that belongs to the Ig superfamily. They exhibit a high degree of structural similarity to molecules in the B7 family. They fulfill a complex function in regulating immune responses, including immunomodulatory roles, as they influence γδ T cells. The biology of BTN molecules indicates that they are capable of inhibiting the immune system's ability to detect antigens within tumors. A dynamic association between BTN molecules and cellular surfaces is also recognized in specific contexts, influencing their biology. Notably, the dynamism of BTN3A1 is associated with the immunosuppression of T cells or the activation of Vγ9Vδ2 T cells. Cancer immunotherapy relies heavily on T cells to modulate immune function within the intricate interaction of the tumor microenvironment (TME). A significant interaction between the TME and antitumor immunity involves the presence of BTN, which should be taken into account when developing immunotherapy. This review explores potential therapeutic applications of BTN molecules, based on the current understanding of their biology.
Asunto(s)
Butirofilinas , Inmunomodulación , Neoplasias , Humanos , Butirofilinas/metabolismo , Butirofilinas/inmunología , Neoplasias/inmunología , Neoplasias/terapia , Neoplasias/tratamiento farmacológico , Inmunomodulación/efectos de los fármacos , Inmunoterapia , Microambiente Tumoral/inmunologíaRESUMEN
In both cancer and infections, diseased cells are presented to human Vγ9Vδ2 T cells through an 'inside out' signalling process whereby structurally diverse phosphoantigen (pAg) molecules are sensed by the intracellular domain of butyrophilin BTN3A11-4. Here we show how-in both humans and alpaca-multiple pAgs function as 'molecular glues' to promote heteromeric association between the intracellular domains of BTN3A1 and the structurally similar butyrophilin BTN2A1. X-ray crystallography studies visualized that engagement of BTN3A1 with pAgs forms a composite interface for direct binding to BTN2A1, with various pAg molecules each positioned at the centre of the interface and gluing the butyrophilins with distinct affinities. Our structural insights guided mutagenesis experiments that led to disruption of the intracellular BTN3A1-BTN2A1 association, abolishing pAg-mediated Vγ9Vδ2 T cell activation. Analyses using structure-based molecular-dynamics simulations, 19F-NMR investigations, chimeric receptor engineering and direct measurement of intercellular binding force revealed how pAg-mediated BTN2A1 association drives BTN3A1 intracellular fluctuations outwards in a thermodynamically favourable manner, thereby enabling BTN3A1 to push off from the BTN2A1 ectodomain to initiate T cell receptor-mediated γδ T cell activation. Practically, we harnessed the molecular-glue model for immunotherapeutics design, demonstrating chemical principles for developing both small-molecule activators and inhibitors of human γδ T cell function.
Asunto(s)
Butirofilinas , Activación de Linfocitos , Fosfoproteínas , Receptores de Antígenos de Linfocitos T gamma-delta , Linfocitos T , Animales , Humanos , Antígenos CD/inmunología , Antígenos CD/metabolismo , Butirofilinas/inmunología , Butirofilinas/metabolismo , Camélidos del Nuevo Mundo/inmunología , Simulación de Dinámica Molecular , Fosfoproteínas/inmunología , Fosfoproteínas/metabolismo , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Linfocitos T/citología , Linfocitos T/inmunología , Linfocitos T/metabolismo , Cristalografía por Rayos X , Resonancia Magnética Nuclear Biomolecular , TermodinámicaRESUMEN
Vγ9Vδ2 T cells have been reported to participate to the immune response against infectious diseases such as the Q fever caused by Coxiella burnetii infection. Indeed, the number and proportion of Vγ9Vδ2 T cells are increased during the acute phase of Q fever. Human Vγ9Vδ2 T cell responses are triggered by phosphoantigens (pAgs) produced by pathogens and malignant cells, that are sensed via the membrane receptors butyrophilin-3A1 (BTN3A1) and -2A1 (BTN2A1). Here, by using CRISPR-Cas9 inactivation in THP-1 cells, we show that BTN3A and BTN2A are required to Vγ9Vδ2 T cell response to C. burnetii infection, though not directly involved in the infection process. Furthermore, C. burnetii-infected monocytes display increased BTN3A and BTN2A expression and induce Vγ9Vδ2 T cell activation that can be inhibited by specific antagonist mAb. More importantly, we show that the antimicrobial functions of Vγ9Vδ2 T cells towards C. burnetii are enhanced in the presence of an BTN3A activating antibody. This supports the role of Vγ9Vδ2 T cells in the control of C. burnetii infection and argues in favor of targeting these cells as an alternative treatment strategy for infectious diseases caused by intracellular bacteria.
Asunto(s)
Antígenos CD , Butirofilinas , Enfermedades Transmisibles , Coxiella burnetii , Fiebre Q , Antígenos CD/inmunología , Butirofilinas/inmunología , Humanos , Fiebre Q/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Linfocitos T/inmunologíaRESUMEN
Rheumatoid arthritis (RA) is an autoimmune disorder characterized by persistent inflammatory responses in target tissues and organs, resulting in the destruction of joints. Collagen type II (CII)-induced arthritis (CIA) is the most used animal model for human RA. Although BTN2A2 protein has been previously shown to inhibit T cell functions in vitro, its effect on autoimmune arthritis has not been reported. In this study, we investigate the ability of a recombinant BTN2A2-IgG2a Fc (BTN2A2-Ig) fusion protein to treat CIA. We show here that administration of BTN2A2-Ig attenuates established CIA, as compared with control Ig protein treatment. This is associated with reduced activation, proliferation and Th1/Th17 cytokine production of T cells in BTN2A2-Ig-treated CIA mice. BTN2A2-Ig also inhibits CII-specific T cell proliferation and Th1/Th17 cytokine production. Although the percentage of effector T cells is decreased in BTN2A2-Ig-treated CIA mice, the proportions of naive T cells and regulatory T cells is increased. Furthermore, BTN2A2-Ig reduces the percentage of proinflammatory M1 macrophages but increases the percentage of anti-inflammatory M2 macrophages in the CIA mice. Our results suggest that BTN2A2-Ig protein has the potential to be used in the treatment of collagen-induced arthritis models.
Asunto(s)
Artritis Experimental/inmunología , Butirofilinas/inmunología , Proteínas Recombinantes de Fusión/inmunología , Células Th17/inmunología , Animales , Artritis Experimental/inducido químicamente , Colágeno Tipo II/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , Células Th17/citologíaRESUMEN
Butyrophilins, which are members of the extended B7 family of immunoregulators structurally related to the B7 family, have diverse functions on immune cells as co-stimulatory and co-inhibitory molecules. Despite recent advances in the understanding on butyrophilins' role on adaptive immune cells during infectious or autoimmune diseases, nothing is known about their role in bone homeostasis. Here, we analyzed the role of one specific butyrophilin, namely Btn2a2, as we have recently shown that Btn2a2 is expressed on the monocyte/macrophage lineage that also gives rise to bone degrading osteoclasts. We found that expression of Btn2a2 on monocytes and pre-osteoclasts is upregulated by the receptor activator of nuclear factor κ-B ligand (RANKL), an essential protein required for osteoclast formation. Interestingly, in Btn2a2-deficient osteoclasts, typical osteoclast marker genes (Nfatc1, cathepsin K, TRAP, and RANK) were downregulated following RANKL stimulation. In vitro osteoclast assays resulted in decreased TRAP positive osteoclast numbers in Btn2a2-deficient cells. However, Btn2a2-deficient osteoclasts revealed abnormal fusion processes shown by their increased size. In vivo steady state µCT and histological analysis of bone architecture in complete Btn2a2-deficient mice showed differences in bone parameters further highlighting the fine-tuning effect of BTN2a2. Moreover, in rheumatoid arthritis patients and experimental arthritis, we detected significantly decreased serum levels of the secreted soluble Btn2a2 protein. Taken together, we identified the involvement of the immunomodulatory molecule Btn2a2 in osteoclast differentiation with potential future implications in basic and translational osteoimmunology.
Asunto(s)
Resorción Ósea/inmunología , Butirofilinas/inmunología , Osteoclastos/citología , Animales , Artritis Experimental/sangre , Artritis Reumatoide/sangre , Butirofilinas/sangre , Butirofilinas/genética , Diferenciación Celular , Femenino , Humanos , Inmunomodulación , Masculino , Ratones Endogámicos DBA , Ratones Noqueados , Monocitos , Osteoclastos/inmunología , Ligando RANK , Linfocitos T/inmunología , Tibia , Microtomografía por Rayos XRESUMEN
Gamma-delta (γδ) T cells express T cell receptors (TCR) that are preconfigured to recognize signs of pathogen infection. In primates, γδ T cells expressing the Vγ9Vδ2 TCR innately recognize (E)-4-hydroxy-3-methyl-but- 2-enyl pyrophosphate (HMBPP), a product of the 2-C-methyl-D-erythritol 4- phosphate (MEP) pathway in bacteria that is presented in infected cells via interaction with members of the B7 family of costimulatory molecules butyrophilin (BTN) 3A1 and BTN2A1. In humans, Listeria monocytogenes (Lm) vaccine platforms have the potential to generate potent Vγ9Vδ2 T cell recognition. To evaluate the activation of Vγ9Vδ2 T cells by Lm-infected human monocyte-derived dendritic cells (Mo-DC) we engineered Lm strains that lack components of the MEP pathway. Direct infection of Mo-DC with these bacteria were unchanged in their ability to activate CD107a expression in Vγ9Vδ2 T cells despite an inability to synthesize HMBPP. Importantly, functional BTN3A1 was essential for this activation. Unexpectedly, we found that cytoplasmic entry of Lm into human dendritic cells resulted in upregulation of cholesterol metabolism in these cells, and the effect of pathway regulatory drugs suggest this occurs via increased synthesis of the alternative endogenous Vγ9Vδ2 ligand isoprenyl pyrophosphate (IPP) and/or its isomer dimethylallyl pyrophosphate (DMAPP). Thus, following direct infection, host pathways regulated by cytoplasmic entry of Lm can trigger Vγ9Vδ2 T cell recognition of infected cells without production of the unique bacterial ligand HMBPP.
Asunto(s)
Células Dendríticas/inmunología , Listeria monocytogenes/inmunología , Monocitos/inmunología , Organofosfatos/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Linfocitos T/inmunología , Butirofilinas/inmunología , Células Cultivadas , Hemiterpenos/inmunología , Humanos , Activación de Linfocitos/inmunología , Proteína 1 de la Membrana Asociada a los Lisosomas/inmunología , Compuestos Organofosforados/inmunología , Unión Proteica/inmunologíaRESUMEN
Butyrophilins (BTNs) belong to the immunoglobulin superfamily of transmembrane proteins and play a role in the regulation of lymphocyte activation, several autoimmune diseases, and the progression of human cancers. However, the associated clinicopathologic characteristics and prognostic value of BTNs in breast cancer remain unknown. This study aimed to discover potential key related BTN genes and signaling pathways in breast cancer, which could provide new insights for immune-based strategies. In the present study, the mRNA expression level and prognostic value of BTN2A1, BTN3A1, BTN3A2, BTN3A3, BTNL2, BTNL9, ERMAP, and MOG were measured. Up-regulation of these genes was significantly correlated with improved overall and relapse-free survival. We then analyzed the prognostic outcomes of breast cancer subtypes, genetic alterations, interaction networks, and the functional enrichment of eight BTN family genes. Our results showed that these eight genes played essential roles in tumor progression. Furthermore, an immune infiltration analysis indicated that most candidate BTN family members were associated with intratumoral immune cell infiltration, especially that of γδ T cells. Finally, gene set enrichment analysis for a single hub gene revealed that each BTN gene played a vital role in tumor progression through immune signaling pathways. These findings provided new insights into breast cancer pathogenesis and identified eight potential biomarkers for breast cancer.
Asunto(s)
Biomarcadores de Tumor/inmunología , Neoplasias de la Mama/inmunología , Butirofilinas/inmunología , Adulto , Anciano , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Butirofilinas/biosíntesis , Butirofilinas/genética , Femenino , Genómica , Humanos , Linfocitos Infiltrantes de Tumor/inmunología , Persona de Mediana Edad , Pronóstico , Proteómica , TranscriptomaRESUMEN
BACKGROUND: The Scianna (SC) blood group system comprises seven antigens. They reside on the erythroblast membrane-associated glycoprotein (ERMAP). The ERMAP and RHCE genes are juxtaposed to each other on chromosome 1. We report a novel SC antigen. STUDY DESIGN AND METHODS: Blood samples came from a patient and his two sisters in Saudi Arabia. To investigate the antibody specificity we used the column agglutination technique and soluble recombinant ERMAP protein. The significance of anti-SCAR was evaluated by the transfusion history and a monocyte monolayer assay. We determined the genomic sequence of ERMAP and RHCE genes. RESULTS: The patient's serum showed an antibody of titer 8 against a high-prevalence antigen. The soluble recombinant ERMAP protein inhibited the antibody. The propositus genotyped homozygous for an ERMAP:c.424C>G variant, for which his sisters were heterozygous. The c.424C>G variant occurred in the SC*01 allele in one haplotype with the RHCE*03 (RHCE*cE) allele. No signs of hemolysis occurred following an incompatible blood transfusion. The monocyte monolayer assay was negative. CONCLUSIONS: We characterized a high-prevalence antigen, with the proposed name "SCAR," which is the eighth antigen of the Scianna blood group system (proposed designation 013.008). Individuals homozygous for ERMAP:p.(Gln142Glu) protein variant can produce anti-SCAR. Although we did not observe any sign of hemolysis at this time, the anti-SCAR prompted a change of the treatment regimen. A review of the known reports indicated that all SC alloantibodies of sufficient titer should be considered capable of causing hemolysis.
Asunto(s)
Anemia de Células Falciformes/terapia , Antígenos de Grupos Sanguíneos/genética , Butirofilinas/genética , Reacción a la Transfusión/sangre , Alelos , Anemia de Células Falciformes/diagnóstico , Anemia de Células Falciformes/genética , Antidrepanocíticos/uso terapéutico , Antígenos de Grupos Sanguíneos/inmunología , Transfusión Sanguínea/métodos , Butirofilinas/inmunología , Femenino , Genotipo , Haplotipos , Heterocigoto , Homocigoto , Humanos , Hidroxiurea/uso terapéutico , Isoanticuerpos/genética , Masculino , Monocitos/metabolismo , Polimorfismo de Nucleótido Simple , Prevalencia , Sistema del Grupo Sanguíneo Rh-Hr/genética , Sistema del Grupo Sanguíneo Rh-Hr/inmunología , Arabia Saudita/epidemiología , Reacción a la Transfusión/genética , Adulto Joven , Talasemia beta/complicacionesRESUMEN
Gamma delta (γδ) T cells which combine both innate and adaptive potential have extraordinary properties. Indeed, their strong cytotoxic and pro-inflammatory activity allows them to kill a broad range of tumor cells. Several studies have demonstrated that γδ T cells are an important component of tumor-infiltrated lymphocytes in patients affected by different types of cancer. Tumor-infiltrating γδ T cells are also considered as a good prognostic marker in many studies, though the presence of these cells is associated with poor prognosis in breast and colon cancers. The tumor microenvironment seems to drive γδ T-cell differentiation toward a tumor-promoting or a tumor-controlling phenotype, which suggests that some tumor microenvironments can limit the effectiveness of γδ T cells.The major γδ T-cell subsets in human are the Vγ9Vδ2 T cells that are specifically activated by phosphoantigens. This unique antigenic activation process operates in a framework that requires the expression of butyrophilin 3A (BTN3A) molecules. Interestingly, there is some evidence that BTN3A expression may be regulated by the tumor microenvironment. Given their strong antitumoral potential, Vγ9Vδ2 T cells are used in therapeutic approaches either by ex vivo culture and amplification, and then adoptive transfer to patients or by direct stimulation to propagate in vivo. These strategies have demonstrated promising initial results, but greater potency is needed. Combining Vγ9Vδ2 T-cell immunotherapy with systemic approaches to restore antitumor immune response in tumor microenvironment may improve efficacy.In this chapter, we first review the basic features of γδ T cells and their roles in the tumor microenvironment and then analyze the advances about the understanding of these cells' activation in tumors and why this represent unique challenges for therapeutics, and finally we discuss γδ T-cell-based therapeutic strategies and future perspectives of their development.
Asunto(s)
Neoplasias/inmunología , Subgrupos de Linfocitos T/citología , Microambiente Tumoral/inmunología , Butirofilinas/inmunología , Diferenciación Celular , Humanos , Activación de Linfocitos , Neoplasias/terapia , Receptores de Antígenos de Linfocitos T gamma-delta , Subgrupos de Linfocitos T/inmunologíaRESUMEN
Gamma delta (γδ) T cells infiltrate most human tumors, but current immunotherapies fail to exploit their in situ major histocompatibility complex-independent tumoricidal potential. Activation of γδ T cells can be elicited by butyrophilin and butyrophilin-like molecules that are structurally similar to the immunosuppressive B7 family members, yet how they regulate and coordinate αß and γδ T cell responses remains unknown. Here, we report that the butyrophilin BTN3A1 inhibits tumor-reactive αß T cell receptor activation by preventing segregation of N-glycosylated CD45 from the immune synapse. Notably, CD277-specific antibodies elicit coordinated restoration of αß T cell effector activity and BTN2A1-dependent γδ lymphocyte cytotoxicity against BTN3A1+ cancer cells, abrogating malignant progression. Targeting BTN3A1 therefore orchestrates cooperative killing of established tumors by αß and γδ T cells and may present a treatment strategy for tumors resistant to existing immunotherapies.
Asunto(s)
Antígenos CD/inmunología , Butirofilinas/antagonistas & inhibidores , Butirofilinas/inmunología , Linfocitos Intraepiteliales/inmunología , Neoplasias Ováricas/inmunología , Neoplasias Ováricas/terapia , Animales , Anticuerpos Monoclonales/uso terapéutico , Antígenos CD/genética , Butirofilinas/genética , Femenino , Humanos , Inmunoterapia/métodos , Ratones , Ratones Transgénicos , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The butyrophilins (BTNs) represent a unique family of immunoglobulin. They were considered to be involved in milk lactation after their discovery in 1981. With the development of research, an increasing number of research revealed that BTNs play important roles in immune regulation [1992-2019]. Our research aimed to summarize the BTN research status and their relationship with lung cancers and breast cancers by bibliometrics and bioinformatics methods. Our results indicate that the researches on immune-regulatory functions of BTNs gradually developed from 1992 to 2006, whereas they increased quickly after 2007. There are international cooperations among 56 countries, of which the United States is the most active one with the highest number of studies as well as highest citations. By coauthorship and cocitation analysis, we showed that Adrian Hayday, who is active in γδ T-cell field, was an active author in BTN publications with average year of 2015 and led a subfield. By keywords co-occurrence analysis, we found that γδ T cell, which is an important cancer immune regulator, is one important hotspot. Finally, we found that several BTN members' expression levels were significantly correlated with prognosis of lung cancer and breast cancer patients. Thus, these BTNs might play immune regulatory effects and could serve as potential biomarkers for cancer.
Asunto(s)
Bibliometría , Butirofilinas/historia , Butirofilinas/inmunología , Neoplasias/inmunología , Historia del Siglo XX , Historia del Siglo XXI , Humanos , PronósticoRESUMEN
Butyrophilin-like (Btnl) genes are emerging as major epithelial determinants of tissue-associated γδ T cell compartments. Thus, the development of signature, murine TCRγδ+ intraepithelial lymphocytes (IEL) in gut and skin depends on Btnl family members, Btnl1 and Skint1, respectively. In seeking mechanisms underlying these profound effects, we now show that normal gut and skin γδ IEL development additionally requires Btnl6 and Skint2, respectively, and furthermore that different Btnl heteromers can seemingly shape different intestinal γδ+ IEL repertoires. This formal genetic evidence for the importance of Btnl heteromers also applied to the steady-state, since sustained Btnl expression is required to maintain the signature TCR.Vγ7+ IEL phenotype, including specific responsiveness to Btnl proteins. In sum, Btnl proteins are required to select and to maintain the phenotypes of tissue-protective γδ IEL compartments, with combinatorially diverse heteromers having differential impacts on different IEL subsets.
Asunto(s)
Butirofilinas/metabolismo , Inmunidad Celular , Linfocitos Intraepiteliales/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Animales , Butirofilinas/genética , Butirofilinas/inmunología , Perfilación de la Expresión Génica , Mucosa Intestinal/citología , Mucosa Intestinal/inmunología , Linfocitos Intraepiteliales/metabolismo , Ratones , Ratones Transgénicos , Receptores de Antígenos de Linfocitos T gamma-delta/inmunologíaRESUMEN
γ9δ2T cells play a major role in cancer immune surveillance, yet the clinical translation of their in vitro promise remains challenging. To address limitations of previous clinical attempts using expanded γ9δ2T cells, we explored the clonal diversity of γ9δ2T cell repertoires and characterized their target. We demonstrated that only a fraction of expanded γ9δ2T cells was active against cancer cells and that activity of the parental clone, or functional avidity of selected γ9δ2 T cell receptors (γ9δ2TCRs), was not associated with clonal frequency. Furthermore, we analyzed the target-receptor interface and provided a 2-receptor, 3-ligand model. We found that activation was initiated by binding of the γ9δ2TCR to BTN2A1 through the regions between CDR2 and CDR3 of the TCR γ chain and modulated by the affinity of the CDR3 region of the TCRδ chain, which was phosphoantigen independent (pAg independent) and did not depend on CD277. CD277 was secondary, serving as a mandatory coactivating ligand. We found that binding of CD277 to its putative ligand did not depend on the presence of γ9δ2TCR, did depend on usage of the intracellular CD277, created pAg-dependent proximity to BTN2A1, enhanced cell-cell conjugate formation, and stabilized the immunological synapse (IS). This process critically depended on the affinity of the γ9δ2TCR and required membrane flexibility of the γ9δ2TCR and CD277, facilitating their polarization and high-density recruitment during IS formation.
Asunto(s)
Proliferación Celular , Activación de Linfocitos , Modelos Inmunológicos , Neoplasias/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Linfocitos T/inmunología , Antígenos de Neoplasias/inmunología , Butirofilinas/inmunología , Humanos , Células Jurkat , Proteínas de Neoplasias/inmunología , Neoplasias/patología , Linfocitos T/patologíaRESUMEN
Vγ9Vδ2 T cells respond in a TCR-dependent fashion to both microbial and host-derived pyrophosphate compounds (phosphoantigens, or P-Ag). Butyrophilin-3A1 (BTN3A1), a protein structurally related to the B7 family of costimulatory molecules, is necessary but insufficient for this process. We performed radiation hybrid screens to uncover direct TCR ligands and cofactors that potentiate BTN3A1's P-Ag sensing function. These experiments identified butyrophilin-2A1 (BTN2A1) as essential to Vγ9Vδ2 T cell recognition. BTN2A1 synergised with BTN3A1 in sensitizing P-Ag-exposed cells for Vγ9Vδ2 TCR-mediated responses. Surface plasmon resonance experiments established Vγ9Vδ2 TCRs used germline-encoded Vγ9 regions to directly bind the BTN2A1 CFG-IgV domain surface. Notably, somatically recombined CDR3 loops implicated in P-Ag recognition were uninvolved. Immunoprecipitations demonstrated close cell-surface BTN2A1-BTN3A1 association independent of P-Ag stimulation. Thus, BTN2A1 is a BTN3A1-linked co-factor critical to Vγ9Vδ2 TCR recognition. Furthermore, these results suggest a composite-ligand model of P-Ag sensing wherein the Vγ9Vδ2 TCR directly interacts with both BTN2A1 and an additional ligand recognized in a CDR3-dependent manner.
Asunto(s)
Antígenos/inmunología , Butirofilinas/inmunología , Células Germinativas/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Linfocitos T/inmunología , Animales , Antígenos/metabolismo , Antígenos CD/química , Antígenos CD/inmunología , Antígenos CD/metabolismo , Butirofilinas/química , Butirofilinas/metabolismo , Células CHO , Cricetinae , Cricetulus , Células Germinativas/metabolismo , Células HEK293 , Humanos , Fosforilación , Unión Proteica , Multimerización de Proteína , Receptores de Antígenos de Linfocitos T gamma-delta/química , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Linfocitos T/metabolismoRESUMEN
Vγ9Vδ2 T cells are a major γδ T cell population in the human blood expressing a characteristic Vγ9JP rearrangement paired with Vδ2. This cell subset is activated in a TCR-dependent and MHC-unrestricted fashion by so-called phosphoantigens (PAgs). PAgs can be microbial [(E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate, HMBPP] or endogenous (isopentenyl pyrophosphate, IPP) and PAg sensing depends on the expression of B7-like butyrophilin (BTN3A, CD277) molecules. IPP increases in some transformed or aminobisphosphonate-treated cells, rendering those cells a target for Vγ9Vδ2 T cells in immunotherapy. Yet, functional Vγ9Vδ2 T cells have only been described in humans and higher primates. Using a genome-based study, we showed in silico translatable genes encoding Vγ9, Vδ2, and BTN3 in a few nonprimate mammalian species. Here, with the help of new monoclonal antibodies, we directly identified a T cell population in the alpaca (Vicugna pacos), which responds to PAgs in a BTN3-dependent fashion and shows typical TRGV9- and TRDV2-like rearrangements. T cell receptor (TCR) transductants and BTN3-deficient human 293T cells reconstituted with alpaca or human BTN3 or alpaca/human BTN3 chimeras showed that alpaca Vγ9Vδ2 TCRs recognize PAg in the context of human and alpaca BTN3. Furthermore, alpaca BTN3 mediates PAg recognition much better than human BTN3A1 alone and this improved functionality mapped to the transmembrane/cytoplasmic part of alpaca BTN3. In summary, we found remarkable similarities but also instructive differences of PAg-recognition by human and alpaca, which help in better understanding the molecular mechanisms controlling the activation of this prominent population of γδ T cells.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Butirofilinas/metabolismo , Hemiterpenos/farmacología , Activación de Linfocitos/inmunología , Compuestos Organofosforados/farmacología , Subgrupos de Linfocitos T/inmunología , Animales , Butirofilinas/antagonistas & inhibidores , Butirofilinas/genética , Butirofilinas/inmunología , Sistemas CRISPR-Cas , Camélidos del Nuevo Mundo , Femenino , Células HEK293 , Humanos , Activación de Linfocitos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Unión Proteica , Receptores de Antígenos de Linfocitos T gamma-delta/efectos de los fármacos , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Subgrupos de Linfocitos T/efectos de los fármacos , Subgrupos de Linfocitos T/metabolismoRESUMEN
Gamma delta (γδ) T cells are essential to protective immunity. In humans, most γδ T cells express Vγ9Vδ2+ T cell receptors (TCRs) that respond to phosphoantigens (pAgs) produced by cellular pathogens and overexpressed by cancers. However, the molecular targets recognized by these γδTCRs are unknown. Here, we identify butyrophilin 2A1 (BTN2A1) as a key ligand that binds to the Vγ9+ TCR γ chain. BTN2A1 associates with another butyrophilin, BTN3A1, and these act together to initiate responses to pAg. Furthermore, binding of a second ligand, possibly BTN3A1, to a separate TCR domain incorporating Vδ2 is also required. This distinctive mode of Ag-dependent T cell activation advances our understanding of diseases involving pAg recognition and creates opportunities for the development of γδ T cell-based immunotherapies.
Asunto(s)
Antígenos de Neoplasias/inmunología , Butirofilinas/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Linfocitos T/inmunología , Antígenos CD/química , Antígenos CD/inmunología , Butirofilinas/química , Butirofilinas/genética , Línea Celular Tumoral , Humanos , Ligandos , Activación de Linfocitos , Fosforilación , Dominios Proteicos , Multimerización de ProteínaRESUMEN
As interest in γδ T cells grows rapidly, what key points are emerging, and where is caution warranted? γδ T cells fulfill critical functions, as reflected in associations with vaccine responsiveness and cancer survival in humans and ever more phenotypes of γδ T cell-deficient mice, including basic physiological deficiencies. Such phenotypes reflect activities of distinct γδ T cell subsets, whose origins offer interesting insights into lymphocyte development but whose variable evolutionary conservation can obfuscate translation of knowledge from mice to humans. By contrast, an emerging and conserved feature of γδ T cells is their "adaptate" biology: an integration of adaptive clonally-restricted specificities, innate tissue-sensing, and unconventional recall responses that collectively strengthen host resistance to myriad challenges. Central to adaptate biology are butyrophilins and other γδ cell regulators, the study of which should greatly enhance our understanding of tissue immunogenicity and immunosurveillance and guide intensifying clinical interest in γδ cells and other unconventional lymphocytes.