RESUMO
HLA class I (HLA-I) glycoproteins drive immune responses by presenting antigens to cognate CD8+ T cells. This process is often hijacked by tumors and pathogens for immune evasion. Because options for restoring HLA-I antigen presentation are limited, we aimed to identify druggable HLA-I pathway targets. Using iterative genome-wide screens, we uncovered that the cell surface glycosphingolipid (GSL) repertoire determines effective HLA-I antigen presentation. We show that absence of the protease SPPL3 augmented B3GNT5 enzyme activity, resulting in upregulation of surface neolacto-series GSLs. These GSLs sterically impeded antibody and receptor interactions with HLA-I and diminished CD8+ T cell activation. Furthermore, a disturbed SPPL3-B3GNT5 pathway in glioma correlated with decreased patient survival. We show that the immunomodulatory effect could be reversed through GSL synthesis inhibition using clinically approved drugs. Overall, our study identifies a GSL signature that inhibits immune recognition and represents a potential therapeutic target in cancer, infection, and autoimmunity.
Assuntos
Ácido Aspártico Endopeptidases/metabolismo , Linfócitos T CD8-Positivos/imunologia , Glioma/imunologia , Glicoesfingolipídeos/metabolismo , Glicosiltransferases/metabolismo , Antígenos HLA/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Imunoterapia/métodos , Apresentação de Antígeno , Ácido Aspártico Endopeptidases/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Glioma/mortalidade , Glicoesfingolipídeos/imunologia , Antígenos HLA/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Ativação Linfocitária , Transdução de Sinais , Análise de Sobrevida , Evasão TumoralRESUMO
MHC class I molecules play an important role in adaptive immune responses against intracellular pathogens. These molecules are highly polymorphic, and many allotypes have been characterized. In a transplantation setting, a mismatch between MHC allotypes may initiate an alloimmune response. Rhesus macaques (Macaca mulatta, Mamu) are valuable as a preclinical model species in transplantation research as well as to evaluate the safety and efficacy of vaccine candidates. In both lines of research, the availability of nonhuman primate MHC-reactive mAbs may enable in vitro monitoring and detection of presence of particular Mamu molecules. In this study, we screened a collection of thoroughly characterized HLA class I-specific human mAbs for cross-reactivity with rhesus macaque MHC class I allotypes. Two mAbs, OK4F9 and OK4F10, recognize an epitope that is defined by isoleucine (I) at amino acid position 142 that is present on the Indian rhesus macaque Mamu-B*008:01 allotype, which is an allotype known to be associated with elite control of SIV replication. The reactive pattern of a third mAb, MUS4H4, is more complex and includes an epitope shared on Mamu-A2*05:01 and -B*001:01-encoded Ags. This is the first description, to our knowledge, of human HLA-reactive mAbs that can recognize Mamu allotypes, and these can be useful tools for in vitro monitoring the presence of the relevant allelic products. Moreover, OK4F9 and OK4F10 can be powerful mAbs for application in SIV-related research.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , HIV-1/fisiologia , Antígenos HLA/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/fisiologia , Síndrome da Imunodeficiência Adquirida/genética , Alelos , Animais , Anticorpos Monoclonais/metabolismo , Reações Cruzadas , Predisposição Genética para Doença , Antígenos HLA/genética , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Alótipos de Imunoglobulina , Células K562 , Macaca mulatta , Polimorfismo Genético , Síndrome de Imunodeficiência Adquirida dos Símios/genética , Replicação ViralRESUMO
A single model system for integrative studies on multiple facets of antigen presentation is lacking. PAKC is a novel panel of ten cell lines knocked out for individual components of the HLA class I antigen presentation pathway. PAKC will accelerate HLA-I research in the fields of oncology, infectiology, and autoimmunity.
Assuntos
Apresentação de Antígeno/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Autoimunidade/imunologia , Humanos , Neoplasias/imunologia , Transdução de Sinais/imunologiaRESUMO
The weight of human leukocyte antigen (HLA) matching in kidney allocation algorithms, especially in the United States, has been devalued in a stepwise manner, supported by the introduction of modern immunosuppression. The intent was further to reduce the observed ethnic/racial disparity, as data emerged associating HLA matching with decreased access to transplantation for African American patients. In recent years, it has been increasingly recognized that a leading cause of graft loss is chronic antibody-mediated rejection, attributed to the development of de novo antibodies against mismatched donor HLA expressed on the graft. These antibodies are most frequently against donor HLA-DQ molecules. Beyond their impact on graft survival, generation of de novo donor-specific HLA antibodies also leads to increased sensitization, as measured by panel-reactive antibody metrics. Consequently, access to transplantation for patients returning to the waitlist in need of a second transplant is compromised. Herein, we address the implications of reduced HLA matching policies in kidney allocation. We highlight the observed diminished outcome data, the significant financial burden, the long-term health consequences, and, more important, the unintended consequences. We further provide recommendations to examine the impact of donor-recipient HLA class II and specifically HLA-DQα1ß1 mismatching, focusing on collection of appropriate data, application of creative simulation approaches, and reconsideration of best practices to reduce inequalities while optimizing patient outcomes.
Assuntos
Transplante de Rim , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Antígenos HLA , Antígenos HLA-DQ , Teste de Histocompatibilidade , Humanos , Isoanticorpos , Doadores de TecidosRESUMO
After renal transplantation, there is a need for immunosuppressive regimens which effectively prevent allograft rejection, while preserving renal function and minimizing side effects. From this perspective, mesenchymal stromal cell (MSC) therapy is of interest. In this randomized prospective, single-center, open-label trial, we compared MSCs infused 6 and 7 weeks after renal transplantation and early tacrolimus withdrawal with a control tacrolimus group. Primary end point was quantitative evaluation of interstitial fibrosis in protocol biopsies at 4 and 24 weeks posttransplant. Secondary end points included acute rejection, graft loss, death, renal function, adverse events, and immunological responses. Seventy patients were randomly assigned of which 57 patients were included in the final analysis (29 MSC; 28 controls). Quantitative progression of fibrosis failed to show benefit in the MSC group and GFR remained stable in both groups. One acute rejection was documented (MSC group), while subclinical rejection in week 24 protocol biopsies occurred in seven patients (four MSC; three controls). In the MSC group, regulatory T cell numbers were significantly higher compared to controls (p = .014, week 24). In conclusion, early tacrolimus withdrawal with MSC therapy was safe and feasible without increased rejection and with preserved renal function. MSC therapy is a potentially useful approach after renal transplantation.
Assuntos
Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Medula Óssea , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/prevenção & controle , Humanos , Imunossupressores/uso terapêutico , Estudos Prospectivos , TacrolimoRESUMO
Understanding how decidual CD8+ T cell (CD8+ dT) cytotoxicity is regulated and how these cells integrate the competing needs for maternal-fetal tolerance and immunity to infection is an important research and clinical goal. Gene-expression analysis of effector-memory CD8+ dT demonstrated a mixed transcriptional signature of T cell dysfunction, activation, and effector function. High protein expression of coinhibitory molecules PD1, CTLA4, and LAG3, accompanied by low expression of cytolytic molecules suggests that the decidual microenvironment reduces CD8+ dT effector responses to maintain tolerance to fetal antigens. However, CD8+ dT degranulated, proliferated, and produced IFN-γ, TNF-α, perforin, and granzymes upon in vitro stimulation, demonstrating that CD8+ dT are not permanently suppressed and retain the capacity to respond to proinflammatory events, such as infections. The balance between transient dysfunction of CD8+ dT that are permissive of placental and fetal development, and reversal of this dysfunctional state, is crucial in understanding the etiology of pregnancy complications and prevention of congenital infections.
Assuntos
Linfócitos T CD8-Positivos/metabolismo , Decídua/metabolismo , Perfilação da Expressão Gênica/métodos , Tolerância Imunológica/genética , Linfócitos T CD8-Positivos/imunologia , Citomegalovirus/imunologia , Citomegalovirus/fisiologia , Infecções por Citomegalovirus/genética , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/virologia , Feminino , Granzimas/genética , Granzimas/metabolismo , Humanos , Tolerância Imunológica/imunologia , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Perforina/genética , Perforina/metabolismo , Fatores de TempoRESUMO
The future of HLA matching in solid organ transplantation lies in epitope matching. The article by Sapir-Pichhadze et al. provides indirect evidence that there is a difference in immunogenicity between antibody-verified versus non-verified eplets. However, this difference was less clear for HLA class II, showing the need for additional efforts to identify truly immunogenic HLA class II epitope mismatches.
Assuntos
Transplante de Rim , Transplante de Órgãos , Anticorpos , Epitopos , Teste de HistocompatibilidadeRESUMO
In kidney transplantation, eplet mismatches between donor and recipient have been associated with de novo donor-specific antibody development. Eplets are theoretically defined configurations of polymorphic amino acids and require experimental verification to establish whether they can be bound by alloantibodies. Human HLA-specific monoclonal antibodies (mAbs) have been instrumental for this purpose but are largely lacking for HLA class II. In this study, we isolated single HLA-DR-specific memory B cells from peripheral blood of immunized individuals (n = 3) using HLA class II tetramers to generate recombinant human HLA-DR antigen-reactive mAbs (n = 5). Comparison of the amino acid composition of the reactive HLA alleles in relation to the antibody reactivity patterns led to identification of 3 configurations, 70Q 73A, 31F 32Y 37Y, and 14K 25Q recognized, respectively, by HLA-DRB1*01:01, HLA-DRB1*04:01, and HLA-DRB1*07:01 antigen-reactive mAbs. The first 2 correspond to eplets 70QA and 31FYY and can now be considered antibody verified. The latter indicates that eplet 25Q needs to be redefined before being considered as antibody verified. Generation and reactivity analysis of human HLA-DR mAbs allowed for identification of amino acid configurations corresponding to known eplets, whereas the other patterns may be used to redefine eplets with similar, but not identical predicted amino acid composition.
Assuntos
Anticorpos Monoclonais , Antígenos HLA-DR , Doadores de Tecidos , Epitopos , Teste de Histocompatibilidade , Humanos , IsoanticorposRESUMO
Mesenchymal stromal cells (MSC) hold promise as a novel immune-modulatory therapy in organ transplantation. First clinical studies have used autologous MSCs; however, the use of allogeneic "off-the-shelf" MSCs is more sustainable for broad clinical implementation, although with the risk of causing sensitization. We investigated safety and feasibility of allogeneic MSCs in renal transplantation, using a matching strategy that prevented repeated mismatches. Ten patients received two doses of 1.5 × 106 /kg allogeneic MSCs 6 months after transplantation in a single-center nonrandomized phase Ib trial, followed by lowering of tacrolimus (trough level 3 ng/mL) in combination with everolimus and prednisone. Primary end point was safety, measured by biopsy proven acute rejection (BPAR) and graft loss 12 months after transplantation. Immune monitoring was performed before and after infusion. No BPAR or graft loss occurred and renal function remained stable. One patient retrospectively had DSAs against MSCs, formed before infusion. No major alterations in T and B cell populations or plasma cytokines were observed upon MSC infusion. Administration of HLA selected allogeneic MSCs combined with low-dose tacrolimus 6 months after transplantation is safe at least in the first year after renal transplantation. This sets the stage to further explore the efficacy of third-party MSCs in renal transplantation.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Transplante de Rim , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Antígenos HLA , Humanos , Netuno , Estudos RetrospectivosRESUMO
Recognition of non-self structures on donor cells represents the main immunological barrier in solid organ transplantation. The human leukocyte antigens (HLA) are considered the most important non-self (allo)antigens in transplantation. Long-term graft attrition is mainly caused by the formation of alloreactive antibodies that are directed against non-self structures (i.e., epitopes) on cell surface proteins. Recently published data provided evidence for a similar importance of non-HLA mismatches between donors and recipients in acute rejection as well as long-term kidney allograft survival. These data suggest a broader concept of immunological non-self that goes beyond HLA incompatibility and expands the current concept of polymorphic non-self epitopes on cell surface molecules from HLA to non-HLA targets. Amino acid substitutions caused by single nucleotide variants in protein-coding genes or complete loss of gene expression represent the basis for polymorphic residues in both HLA and non-HLA molecules. To better understand these novel insights in non-HLA alloimmunity, we will first review basic principles of the alloimmune response with a focus on the HLA epitope concept in donor-specific antibody formation before discussing key publications on non-HLA antibodies.
Assuntos
Rejeição de Enxerto/imunologia , Sobrevivência de Enxerto , Histocompatibilidade , Transplante de Rim , Epitopos , Antígenos HLA , Humanos , Proteínas de Membrana/imunologiaRESUMO
The aim was to evaluate the association of molecular-level human leukocyte antigen (HLA) mismatching with post-transplant graft survival, rejection, and cardiac allograft vasculopathy (CAV). We retrospectively analyzed all primary cardiac transplant recipients between 01/1984-06/2016. 1167 patients fulfilled inclusion criteria and had HLA typing information available. In 312 donor-recipient pairs, typing at serological split antigen level was available. We used the Epitope MisMatch Algorithm to calculate the number of amino acid differences in antibody-verified HLA eplets (amino acid mismatch load (AAMM)) between donor and recipient. Patients with a higher HLA-DR AAMM load had inferior 1-year graft survival (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.01-1.28). The HLA-AB AAMM load showed no impact on graft survival. In the subgroup with available split-level information, we observed an inferior graft survival for a higher HLA-DR AAMM load 3 months after transplantation (HR, 1.22; 95% CI, 1.04-1.44) and a higher risk for rejection for an increasing HLA-AB (HR, 1.70; 95% CI, 1.29-2.24) and HLA-DR (HR, 1.32; 95% CI, 1.09-1.61) AAMM load. No impact on the development of CAV was found. Molecular-level HLA mismatch analysis could serve as a tool for risk stratification after heart transplantation and might take us one step further into precision medicine.
Assuntos
Sobrevivência de Enxerto , Transplante de Coração , Rejeição de Enxerto , Antígenos HLA , Teste de Histocompatibilidade , Humanos , Estudos RetrospectivosRESUMO
The killer-cell Ig-like receptors (KIRs) play a central role in the immune recognition in infection, pregnancy, and transplantation through their interactions with MHC class I molecules. KIR genes display abundant copy number variation as well as high levels of polymorphism. As a result, it is challenging to characterize this structurally dynamic region. KIR haplotypes have been analyzed in different species using conventional characterization methods, such as Sanger sequencing and Roche/454 pyrosequencing. However, these methods are time-consuming and often failed to define complete haplotypes, or do not reach allele-level resolution. In addition, most analyses were performed on genomic DNA, and thus were lacking substantial information about transcription and its corresponding modifications. In this paper, we present a single-molecule real-time sequencing approach, using Pacific Biosciences Sequel platform to characterize the KIR transcriptomes in human and rhesus macaque (Macaca mulatta) families. This high-resolution approach allowed the identification of novel Mamu-KIR alleles, the extension of reported allele sequences, and the determination of human and macaque KIR haplotypes. In addition, multiple recombinant KIR genes were discovered, all located on contracted haplotypes, which were likely the result of chromosomal rearrangements. The relatively high number of contracted haplotypes discovered might be indicative of selection on small KIR repertoires and/or novel fusion gene products. This next-generation method provides an improved high-resolution characterization of the KIR cluster in humans and macaques, which eventually may aid in a better understanding and interpretation of KIR allele-associated diseases, as well as the immune response in transplantation and reproduction.
Assuntos
Haplótipos/genética , Receptores KIR/genética , Transcriptoma/genética , Alelos , Animais , Variações do Número de Cópias de DNA/genética , Rearranjo Gênico/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Macaca mulatta , Polimorfismo Genético/genéticaRESUMO
Maternal microchimerism (MMc) has been associated with development of allospecific transplant tolerance, antitumor immunity, and cross-generational reproductive fitness, but its mode of action is unknown. We found in a murine model that MMc caused exposure to the noninherited maternal antigens in all offspring, but in some, MMc magnitude was enough to cause membrane alloantigen acquisition (mAAQ; "cross-dressing") of host dendritic cells (DCs). Extracellular vesicle (EV)-enriched serum fractions from mAAQ+, but not from non-mAAQ, mice reproduced the DC cross-dressing phenomenon in vitro. In vivo, mAAQ was associated with increased expression of immune modulators PD-L1 (programmed death-ligand 1) and CD86 by myeloid DCs (mDCs) and decreased presentation of allopeptide+self-MHC complexes, along with increased PD-L1, on plasmacytoid DCs (pDCs). Remarkably, both serum EV-enriched fractions and membrane microdomains containing the acquired MHC alloantigens included CD86, but completely excluded PD-L1. In contrast, EV-enriched fractions and microdomains containing allopeptide+self-MHC did not exclude PD-L1. Adoptive transfer of allospecific transgenic CD4 T cells revealed a "split tolerance" status in mAAQ+ mice: T cells recognizing intact acquired MHC alloantigens proliferated, whereas those responding to allopeptide+self-MHC did not. Using isolated pDCs and mDCs for in vitro culture with allopeptide+self-MHC-specific CD4 T cells, we could replicate their normal activation in non-mAAQ mice, and PD-L1-dependent anergy in mAAQ+ hosts. We propose that EVs provide a physiologic link between microchimerism and split tolerance, with implications for tumor immunity, transplantation, autoimmunity, and reproductive success.
Assuntos
Quimerismo , Células Dendríticas/imunologia , Vesículas Extracelulares/imunologia , Tolerância Imunológica , Transferência Adotiva , Animais , Antígeno B7-2/biossíntese , Antígeno B7-2/imunologia , Antígeno B7-H1/biossíntese , Antígeno B7-H1/imunologia , Linfócitos T CD4-Positivos/imunologia , Feminino , Transfusão Feto-Materna/imunologia , Antígenos H-2/genética , Antígenos H-2/imunologia , Antígeno de Histocompatibilidade H-2D/genética , Antígeno de Histocompatibilidade H-2D/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Isoantígenos/imunologia , Masculino , Troca Materno-Fetal/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Imunológicos , Gravidez , Especificidade do Receptor de Antígeno de Linfócitos TRESUMO
About 10-15% of couples who want to conceive suffer from subfertility, while in 30% of these cases, a male factor plays a role. Levels of particular microRNAs in seminal plasma, including those involved in spermatogenesis, may serve as an indicative parameter for subfertility. We first optimized a protocol for acquiring microRNAs from seminal plasma. Next, using a test-validation strategy in a male cohort, we aimed to identify microRNAs of which the levels are related to semen motility and concentration. By qPCR, 742 microRNAs were profiled in three normozoospermic samples, three seminal samples with a low semen motility (asthenozoospermia), and three with a low semen concentration (oligozoospermia). MicroRNAs showing significant differences between groups were further validated in a second cohort consisting of 40 samples with normozoospermia (control group), 47 samples with asthenozoospermia, and 19 samples with oligozoospermia (of which 74% also low motility). Highest microRNA yields were obtained with the Biofluids RNA extraction kit, with inclusion of MS2 RNA carrier and proteinase K treatment to the protocol, and when 50 µL of seminal plasma was used as input. Exosome isolation prior to RNA extraction did not lead to enhanced yields. In the test cohort, 236 microRNAs could be detected, of which 54 microRNAs showed a difference between groups. Five microRNAs were analyzed in the validation cohort. MiR-34b-5p levels in the control group were significantly higher compared to the asthenozoospermia group (p < 0.05) and compared to the oligozoospermia group (p < 0.001). We optimized microRNA acquirement from seminal plasma and identified microRNA levels in relation to semen concentration and motility. As recent human and mouse studies show that the miR-34 family is a marker of low semen concentration and is crucial in spermatogenesis, seminal plasma miR-34b-5p may represent a suitable candidate to study further as a marker of male subfertility.
Assuntos
MicroRNAs/genética , Sêmen , Contagem de Espermatozoides , Astenozoospermia/diagnóstico , Astenozoospermia/genética , Biomarcadores , Biologia Computacional/métodos , Perfilação da Expressão Gênica , Humanos , Masculino , Oligospermia/diagnóstico , Oligospermia/genética , Prognóstico , Reprodutibilidade dos Testes , Espermatogênese , TranscriptomaRESUMO
Tissue resident lymphocytes are present within many organs, and are presumably transferred at transplantation, but their impact on host immunity is unclear. Here, we examine whether transferred donor natural regulatory CD4 T cells (nT-regs) inhibit host alloimmunity and prolong allograft survival. Transfer of donor-strain lymphocytes was first assessed by identifying circulating donor-derived CD4 T cells in 21 consecutive human lung transplant recipients, with 3 patterns of chimerism apparent: transient, intermediate, and persistent (detectable for up to 6 weeks, 6 months, and beyond 1 year, respectively). The potential for transfer of donor nT-regs was then confirmed by analysis of leukocyte filters recovered from ex vivo normothermic perfusion circuits of human kidneys retrieved for transplantation. Finally, in a murine model of cardiac allograft vasculopathy, depletion of donor CD4 nT-regs before organ recovery resulted in markedly accelerated heart allograft rejection and augmented host effector antibody responses. Conversely, adoptive transfer or purified donor-strain nT-regs inhibited host humoral immunity and prolonged allograft survival, and more effectively so than following administration of recipient nT-regs. In summary, following transplantation, passenger donor-strain nT-regs can inhibit host adaptive immune responses and prolong allograft survival. Isolated donor-derived nT-regs may hold potential as a cellular therapy to improve transplant outcomes.
Assuntos
Rejeição de Enxerto/imunologia , Sobrevivência de Enxerto/imunologia , Transplante de Rim , Transplante de Pulmão , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Aloenxertos , Animais , Linhagem da Célula , Transplante de Coração , Humanos , Sistema Imunitário , Imunidade Humoral , Isoanticorpos/imunologia , Camundongos , Preservação de Órgãos , Perfusão , Doadores de Tecidos , Transplante Homólogo , Resultado do TratamentoRESUMO
Abacavir administration is associated with drug-induced hypersensitivity reactions in HIV+ individuals expressing the HLA-B*57:01 allele. However, the immunological effects of abacavir administration in an HLA-B57 mismatched transplantation setting have not been studied. We hypothesized that abacavir exposure could induce de novo HLA-B57-specific allorecognition. HIV-specific CD8 T cell clones were generated from HIV+ individuals, using single cell sorting based on HIV peptide/HLA tetramer staining. The T cell clones were assayed for alloreactivity against a panel of single HLA-expressing cell lines, in the presence or absence of abacavir. Cytokine assay, CD137 upregulation, and cytotoxicity were used as readout. Abacavir exposure can induce de novo HLA-B57 allorecognition by HIV-specific T cells. A HIV Gag RK9/HLA-A3-specific T cell did exhibit interferon-γ production, CD137 upregulation, and cytolytic effector function against allogeneic HLA-B57, but only in the presence of abacavir. Allorecognition was specific to the virus specificity, HLA restriction, and T cell receptor TRBV use of the T cell. We provide proof-of-principle evidence that administration of a drug could induce specific allorecognition of mismatched HLA molecules in the transplant setting. We suggest that HIV-seropositive recipients of an HLA-B57 mismatched graft should not receive abacavir until further studies are completed.
Assuntos
Fármacos Anti-HIV/efeitos adversos , Didesoxinucleosídeos/efeitos adversos , Hipersensibilidade a Drogas/imunologia , Infecções por HIV/sangue , Antígenos HLA-B/imunologia , Alelos , Linfócitos T CD8-Positivos/imunologia , Citocinas/metabolismo , Infecções por HIV/complicações , Infecções por HIV/imunologia , Soropositividade para HIV/imunologia , Teste de Histocompatibilidade , Humanos , Interferon gama/metabolismo , Leucócitos Mononucleares/citologia , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T/imunologia , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismoRESUMO
Whereas regular allocation avoids unacceptable mismatches on the donor organ, allocation to highly sensitized patients within the Eurotransplant Acceptable Mismatch (AM) program is based on the patient's HLA phenotype plus acceptable antigens. These are HLA antigens to which the patient never made antibodies, as determined by extensive laboratory testing. AM patients have superior long-term graft survival compared with highly sensitized patients in regular allocation. Here, we questioned whether the AM program also results in lower rejection rates. From the PROCARE cohort, consisting of all Dutch kidney transplants in 1995-2005, we selected deceased donor single transplants with a minimum of 1 HLA mismatch and determined the cumulative 6-month rejection incidence for patients in AM or regular allocation. Additionally, we determined the effect of minimal matching criteria of 1 HLA-B plus 1 HLA-DR, or 2 HLA-DR antigens on rejection incidence. AM patients showed significantly lower rejection rates than highly immunized patients in regular allocation, comparable to nonsensitized patients, independent of other risk factors for rejection. In contrast to highly sensitized patients in regular allocation, minimal matching criteria did not affect rejection rates in AM patients. Allocation based on acceptable antigens leads to relatively low-risk transplants for highly sensitized patients with rejection rates similar to those of nonimmunized individuals.
Assuntos
Rejeição de Enxerto/diagnóstico , Antígenos HLA/imunologia , Histocompatibilidade/imunologia , Imunização/métodos , Falência Renal Crônica/imunologia , Transplante de Rim/efeitos adversos , Seleção de Pacientes , Doadores de Tecidos/provisão & distribuição , Feminino , Seguimentos , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/patologia , Sobrevivência de Enxerto/imunologia , Antígenos HLA/química , Teste de Histocompatibilidade , Humanos , Isoanticorpos/efeitos adversos , Falência Renal Crônica/cirurgia , Transplante de Rim/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Prognóstico , Fatores de Risco , Obtenção de Tecidos e Órgãos/métodos , Imunologia de TransplantesRESUMO
Misfolded endoplasmic reticulum (ER) proteins are dislocated towards the cytosol and degraded by the ubiquitin-proteasome system in a process called ER-associated protein degradation (ERAD). During infection with human cytomegalovirus (HCMV), the viral US2 protein targets HLA class I molecules (HLA-I) for degradation via ERAD to avoid elimination by the immune system. US2-mediated degradation of HLA-I serves as a paradigm of ERAD and has facilitated the identification of TRC8 (also known as RNF139) as an E3 ubiquitin ligase. No specific E2 enzymes had previously been described for cooperation with TRC8. In this study, we used a lentiviral CRISPR/Cas9 library targeting all known human E2 enzymes to assess their involvement in US2-mediated HLA-I downregulation. We identified multiple E2 enzymes involved in this process, of which UBE2G2 was crucial for the degradation of various immunoreceptors. UBE2J2, on the other hand, counteracted US2-induced ERAD by downregulating TRC8 expression. These findings indicate the complexity of cellular quality control mechanisms, which are elegantly exploited by HCMV to elude the immune system.
Assuntos
Citomegalovirus/metabolismo , Regulação para Baixo , Receptores Imunológicos/metabolismo , Enzimas de Conjugação de Ubiquitina/metabolismo , Proteínas do Envelope Viral/metabolismo , Sistemas CRISPR-Cas/genética , Testes Genéticos , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Modelos Biológicos , Proteólise , Receptores de Superfície Celular/metabolismo , Células U937 , Regulação para CimaRESUMO
The observation, by Ray Owen and colleagues in 1954, that D-negative women were less likely to form anti-D antibodies against their D-positive fetus if their mother possessed the D-antigen, was not found in all later studies. We hypothesized that breastfeeding, received by the mother, may affect her immunity against non-inherited maternal red blood cell antigens. We studied a cohort of 125 grandmother-mother-child combinations, from a follow-up study of mothers after intrauterine transfusion of the fetus for alloimmune hemolytic disease. For mismatched red blood cell antigens the mother was exposed to, whether or not antibodies were formed, we determined whether her mother, the grandmother, carried these antigens. The duration for which the mothers were breastfed was estimated by way of a questionnaire. Using multivariate logistic regression analyses, the interaction term (non-inherited maternal antigen exposure by categorized breastfeeding period) showed that a longer breastfeeding period was associated with decreased alloimmunization against non-inherited maternal antigens (adjusted odds ratio 0.66; 95% confidence interval 0.48-0.93). Sensitivity analysis with dichotomized (shorter versus longer) breastfeeding periods showed that this lower risk was reached after two months (aOR 0.22; 95% CI 0.07-0.71) and longer duration of breastfeeding did not seem to provide additional protection. These data suggest that oral neonatal exposure to non-inherited maternal red blood cell antigens through breastfeeding for at least two months diminishes the risk of alloimmunization against these antigens when encountered later in life.