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1.
Nucleic Acids Res ; 51(7): 3030-3040, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-36869666

RESUMO

The hybridization and dehybridization of DNA subject to tension is relevant to fundamental genetic processes and to the design of DNA-based mechanobiology assays. While strong tension accelerates DNA melting and decelerates DNA annealing, the effects of tension weaker than 5 pN are less clear. In this study, we developed a DNA bow assay, which uses the bending rigidity of double-stranded DNA (dsDNA) to exert weak tension on a single-stranded DNA (ssDNA) target in the range of 2-6 pN. Combining this assay with single-molecule FRET, we measured the hybridization and dehybridization kinetics between a 15 nt ssDNA under tension and a 8-9 nt oligonucleotide, and found that both the hybridization and dehybridization rates monotonically increase with tension for various nucleotide sequences tested. These findings suggest that the nucleated duplex in its transition state is more extended than the pure dsDNA or ssDNA counterpart. Based on coarse-grained oxDNA simulations, we propose that this increased extension of the transition state is due to steric repulsion between the unpaired ssDNA segments in close proximity to one another. Using linear force-extension relations verified by simulations of short DNA segments, we derived analytical equations for force-to-rate conversion that are in good agreement with our measurements.


Assuntos
DNA , Oligonucleotídeos , Oligonucleotídeos/genética , Hibridização de Ácido Nucleico , DNA/genética , DNA de Cadeia Simples/genética , Fenômenos Mecânicos
2.
Euro Surveill ; 29(28)2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38994600

RESUMO

We investigated a variant of measles virus that encodes three mismatches to the reverse priming site for a widely used diagnostic real-time RT-PCR assay; reduction of sensitivity was hypothesised. We examined performance of the assay in context of the variant using in silico data, synthetic RNA templates and clinical specimens. Sensitivity was reduced observed at low copy numbers for templates encoding the variant sequence. We designed and tested an alternate priming strategy, rescuing the sensitivity of the assay.


Assuntos
Vírus do Sarampo , Sarampo , RNA Viral , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Humanos , Sarampo/diagnóstico , Sarampo/virologia , Vírus do Sarampo/genética , Vírus do Sarampo/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , RNA Viral/genética
3.
Semin Cell Dev Biol ; 86: 3-14, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29499385

RESUMO

Dendritic cells (DC) are bone marrow derived leucocytes that are part of the mononuclear phagocytic system. These are surveillance cells found in all tissues and, as specialised antigen presenting cells, direct immune responses. Membrane molecules on the DC surface form a landscape that defines them as leucocytes and part of the mononuclear phagocytic system, interacts with their environment and directs interactions with other cells. This review describes the DC surface landscape, reflects on the different molecules confirmed to be on their surface and how they provide the basis for manipulation and translation of the potent functions of these cells into new diagnostics and immune therapies for the clinic.


Assuntos
Células Dendríticas/citologia , Fenótipo , Células Dendríticas/imunologia , Humanos
4.
Semin Cell Dev Biol ; 86: 77-88, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29454038

RESUMO

The ability of immune therapies to control cancer has recently generated intense interest. This therapeutic outcome is reliant on T cell recognition of tumour cells. The natural function of dendritic cells (DC) is to generate adaptive responses, by presenting antigen to T cells, hence they are a logical target to generate specific anti-tumour immunity. Our understanding of the biology of DC is expanding, and they are now known to be a family of related subsets with variable features and function. Most clinical experience to date with DC vaccination has been using monocyte-derived DC vaccines. There is now growing experience with alternative blood-derived DC derived vaccines, as well as with multiple forms of tumour antigen and its loading, a wide range of adjuvants and different modes of vaccine delivery. Key insights from pre-clinical studies, and lessons learned from early clinical testing drive progress towards improved vaccines. The potential to fortify responses with other modalities of immunotherapy makes clinically effective "second generation" DC vaccination strategies a priority for cancer immune therapists.


Assuntos
Células Dendríticas/imunologia , Células Dendríticas/transplante , Imunoterapia , Neoplasias/imunologia , Neoplasias/terapia , Humanos , Linfócitos T/imunologia
5.
Haematologica ; 103(4): 655-665, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29351987

RESUMO

Chemotherapy and hematopoietic stem cell transplantation are effective treatments for most Hodgkin lymphoma patients, however there remains a need for better tumor-specific target therapy in Hodgkin lymphoma patients with refractory or relapsed disease. Herein, we demonstrate that membrane CD83 is a diagnostic and therapeutic target, highly expressed in Hodgkin lymphoma cell lines and Hodgkin and Reed-Sternberg cells in 29/35 (82.9%) Hodgkin lymphoma patient lymph node biopsies. CD83 from Hodgkin lymphoma tumor cells was able to trogocytose to surrounding T cells and, interestingly, the trogocytosing CD83+T cells expressed significantly more programmed death-1 compared to CD83-T cells. Hodgkin lymphoma tumor cells secreted soluble CD83 that inhibited T-cell proliferation, and anti-CD83 antibody partially reversed the inhibitory effect. High levels of soluble CD83 were detected in Hodgkin lymphoma patient sera, which returned to normal in patients who had good clinical responses to chemotherapy confirmed by positron emission tomography scans. We generated a human anti-human CD83 antibody, 3C12C, and its toxin monomethyl auristatin E conjugate, that killed CD83 positive Hodgkin lymphoma cells but not CD83 negative cells. The 3C12C antibody was tested in dose escalation studies in non-human primates. No toxicity was observed, but there was evidence of CD83 positive target cell depletion. These data establish CD83 as a potential biomarker and therapeutic target in Hodgkin lymphoma.


Assuntos
Antígenos CD/sangue , Biomarcadores Tumorais/sangue , Doença de Hodgkin/tratamento farmacológico , Imunoglobulinas/sangue , Glicoproteínas de Membrana/sangue , Terapia de Alvo Molecular/métodos , Adolescente , Adulto , Idoso , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Antígenos CD/imunologia , Feminino , Doença de Hodgkin/diagnóstico , Humanos , Imunoglobulinas/imunologia , Masculino , Glicoproteínas de Membrana/imunologia , Pessoa de Meia-Idade , Terapia de Salvação/métodos , Linfócitos T/citologia , Adulto Jovem , Antígeno CD83
6.
J Immunol ; 197(3): 885-98, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27316686

RESUMO

C-type lectin receptors play important roles in immune cell interactions with the environment. We described CD302 as the simplest, single domain, type I C-type lectin receptor and showed it was expressed mainly on the myeloid phagocytes in human blood. CD302 colocalized with podosomes and lamellopodia structures, so we hypothesized that it played a role in cell adhesion or migration. In this study, we used mouse models to obtain further insights into CD302 expression and its potential immunological function. Mouse CD302 transcripts were, as in humans, highest in the liver, followed by lungs, lymph nodes (LN), spleen, and bone marrow. In liver, CD302 was expressed by hepatocytes, liver sinusoidal endothelial cells, and Kupffer cells. A detailed analysis of CD302 transcription in mouse immune cells revealed highest expression by myeloid cells, particularly macrophages, granulocytes, and myeloid dendritic cells (mDC). Interestingly, 2.5-fold more CD302 was found in migratory compared with resident mDC populations and higher CD302 expression in mouse M1 versus M2 macrophages was also noteworthy. CD302 knockout (CD302KO) mice were generated. Studies on the relevant immune cell populations revealed a decrease in the frequency and numbers of migratory mDC within CD302KO LN compared with wild-type LN. In vitro studies showed CD302KO and wild-type DC had an equivalent capacity to undergo maturation, prime T cells, uptake Ags, and migrate toward the CCL19/CCL21 chemokines. Nevertheless, CD302KO migratory DC exhibited reduced in vivo migration into LN, confirming a functional role for CD302 in mDC migration.


Assuntos
Quimiotaxia de Leucócito/fisiologia , Células Dendríticas/metabolismo , Lectinas Tipo C/metabolismo , Receptores de Superfície Celular/metabolismo , Animais , Linhagem Celular , Separação Celular , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Reação em Cadeia da Polimerase
7.
J Immunol ; 197(12): 4613-4625, 2016 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-27837105

RESUMO

CD83 is a member of the Ig gene superfamily, first identified in activated lymphocytes. Since then, CD83 has become an important marker for defining activated human dendritic cells (DC). Several potential CD83 mRNA isoforms have been described, including a soluble form detected in human serum, which may have an immunosuppressive function. To further understand the biology of CD83, we examined its expression in different human immune cell types before and after activation using a panel of mouse and human anti-human CD83 mAb. The mouse anti-human CD83 mAbs, HB15a and HB15e, and the human anti-human CD83 mAb, 3C12C, were selected to examine cytoplasmic and surface CD83 expression, based on their different binding characteristics. Glycosylation of CD83, the CD83 mRNA isoforms, and soluble CD83 released differed among blood DC, monocytes, and monocyte-derived DC, and other immune cell types. A small T cell population expressing surface CD83 was identified upon T cell stimulation and during allogeneic MLR. This subpopulation appeared specifically during viral Ag challenge. We did not observe human CD83 on unstimulated human natural regulatory T cells (Treg), in contrast to reports describing expression of CD83 on mouse Treg. CD83 expression was increased on CD4+, CD8+ T, and Treg cells in association with clinical acute graft-versus-host disease in allogeneic hematopoietic cell transplant recipients. The differential expression and function of CD83 on human immune cells reveal potential new roles for this molecule as a target of therapeutic manipulation in transplantation, inflammation, and autoimmune diseases.


Assuntos
Antígenos CD/metabolismo , Células Dendríticas/imunologia , Doença Enxerto-Hospedeiro/imunologia , Transplante de Células-Tronco Hematopoéticas , Imunoglobulinas/metabolismo , Glicoproteínas de Membrana/metabolismo , Monócitos/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Doença Aguda , Animais , Antígenos CD/genética , Antígenos Virais/imunologia , Células Cultivadas , Glicosilação , Humanos , Imunoglobulinas/genética , Ativação Linfocitária , Glicoproteínas de Membrana/genética , Camundongos , Isoformas de RNA/genética , RNA Mensageiro/genética , Transplante Homólogo , Antígeno CD83
8.
Pharmacol Rev ; 67(4): 731-53, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26240218

RESUMO

Although the earliest­rudimentary­attempts at exploiting the immune system for cancer therapy can be traced back to the late 18th Century, it was not until the past decade that cancer immunotherapeutics have truly entered mainstream clinical practice. Given their potential to stimulate both adaptive and innate antitumor immune responses, dendritic cells (DCs) have come under intense scrutiny in recent years as pharmacological tools for cancer immunotherapy. Conceptually, the clinical effectiveness of this form of active immunotherapy relies on the completion of three critical steps: 1) the DCs used as immunotherapeutic vehicles must properly activate the antitumor immune effector cells of the host, 2) these immune effector cells must be receptive to stimulation by the DCs and be competent to mediate their antitumor effects, which 3) requires overcoming the various immune-inhibitory mechanisms used by the tumor cells. In this review, following a brief overview of the pivotal milestones in the history of cancer immunotherapy, we will introduce the reader to the basic immunobiological and pharmacological principles of active cancer immunotherapy using DCs. We will then discuss how current research is trying to define the optimal parameters for each of the above steps to realize the full clinical potential of DC therapeutics. Given its high suitability for immune interventions, acute myeloid leukemia was chosen here to showcase the latest research trends driving the field of DC-based cancer immunotherapy.


Assuntos
Células Dendríticas/metabolismo , Imunoterapia Ativa/métodos , Neoplasias/imunologia , Neoplasias/terapia , Linfócitos T Citotóxicos/imunologia , Transferência Adotiva/métodos , Anticorpos Monoclonais , Antígenos de Neoplasias/imunologia , Apoptose , Vacinas Anticâncer/imunologia , Técnicas de Cultura de Células , Citocinas/biossíntese , Células Dendríticas/imunologia , Relação Dose-Resposta a Droga , Vias de Administração de Medicamentos , Humanos , Células Matadoras Naturais/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Transdução de Sinais
9.
Immunol Cell Biol ; 94(5): 447-57, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26791160

RESUMO

Human plasmacytoid dendritic cells (pDCs) were considered to be a phenotypically and functionally homogeneous cell population; however, recent analyses indicate potential heterogeneity. This is of major interest, given their importance in the induction of anti-viral responses and their role in creating immunologically permissive environments for human malignancies. For this reason, we investigated the possible presence of human pDC subsets in blood and bone marrow, using unbiased cell phenotype clustering and functional studies. This defined two major functionally distinct human pDC subsets, distinguished by differential expression of CD2. The CD2(hi) and CD2(lo) pDCs represent discontinuous subsets, each with hallmark pDC functionality, including interferon-alpha production. The rarer CD2(hi) pDC subset demonstrated a significant survival advantage over CD2(lo) pDC during stress and upon exposure to glucocorticoids (GCs), which was associated with higher expression of the anti-apoptotic molecule BCL2. The differential sensitivity of these two human pDC subsets to GCs is demonstrated in vivo by a relative increase in CD2(hi) pDC in multiple myeloma patients treated with GCs. Hence, the selective apoptosis of CD2(lo) pDC during stress represents a novel mechanism for the control of innate responses.


Assuntos
Antígenos CD2/metabolismo , Células Dendríticas/metabolismo , Estresse Fisiológico , Apoptose/efeitos dos fármacos , Medula Óssea/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Glucocorticoides/farmacologia , Humanos , Ligantes , Linfonodos/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Receptores Imunológicos/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Receptores Toll-Like/metabolismo
10.
Br J Haematol ; 164(4): 481-95, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24321020

RESUMO

Novel therapies with increased efficacy and decreased toxicity are desperately needed for the treatment of acute myeloid leukaemia (AML). The anti CD33 immunoconjugate, gemtuzumab ozogamicin (GO), was withdrawn with concerns over induction mortality and lack of efficacy. However a number of recent trials suggest that, particularly in AML with favourable cytogenetics, GO may improve overall survival. This data and the development of alternative novel monoclonal antibodies (mAb) have renewed interest in the area. Leukaemic stem cells (LSC) are identified as the subset of AML blasts that reproduces the leukaemic phenotype upon transplantation into immunosuppressed mice. AML relapse may be caused by chemoresistant LSC and this has refocused interest on identifying and targeting antigens specific for LSC. Several mAb have been developed that target LSC effectively in xenogeneic models but only a few have begun clinical evaluation. Antibody engineering may improve the activity of potential new therapeutics for AML. The encouraging results seen with bispecific T cell-engaging mAb-based molecules against CD19 in the treatment of B-cell acute lymphobalstic leukaemia, highlight the potential efficacy of engineered antibodies in the treatment of acute leukaemia. Potent engineered mAb, possibly targeting novel LSC antigens, offer hope for improving the current poor prognosis for AML.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Humanos , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/radioterapia
11.
Blood ; 120(10): 2055-63, 2012 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-22705596

RESUMO

The transfer of membrane proteins between cells during contact, known as trogocytosis, can create novel cells with a unique phenotype and altered function. We demonstrate that trogocytosis is more common in multiple myeloma (MM) than chronic lymphocytic leukemia and Waldenstrom macroglobulinaemia; that T cells are more probable to be recipients than B or natural killer cells; that trogocytosis occurs independently of either the T-cell receptor or HLA compatibility; and that after trogocytosis, T cells with acquired antigens can become novel regulators of T-cell proliferation. We screened 168 patients with MM and found that CD86 and human leukocyte antigen G (HLA-G) were antigens commonly acquired by T cells from malignant plasma cells. CD3+ CD86acq+ and CD3+ HLA-Gacq+ cells were more prevalent in bone marrow than peripheral blood samples. The presence of either CD86 or HLA-G on malignant plasma cells was associated with a poor prognosis. CD38++ side population cells expressed HLA-G, suggesting that these putative myeloma stem cells could generate immune tolerance. HLA-G+ T cells had a regulatory potency similar to natural Tregs, thus providing another novel mechanism for MM to avoid effective immune surveillance.


Assuntos
Antígeno B7-2/imunologia , Antígenos HLA-G/imunologia , Leucemia Linfocítica Crônica de Células B/metabolismo , Mieloma Múltiplo/metabolismo , Plasmócitos/imunologia , Macroglobulinemia de Waldenstrom/metabolismo , Linfócitos B/imunologia , Linfócitos B/metabolismo , Biomarcadores/análise , Membrana Celular/imunologia , Membrana Celular/metabolismo , Proliferação de Células , Humanos , Tolerância Imunológica , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Leucemia Linfocítica Crônica de Células B/imunologia , Leucemia Linfocítica Crônica de Células B/mortalidade , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/mortalidade , Especificidade de Órgãos , Plasmócitos/metabolismo , Prognóstico , Transporte Proteico/imunologia , Taxa de Sobrevida , Linfócitos T/imunologia , Linfócitos T/metabolismo , Macroglobulinemia de Waldenstrom/imunologia , Macroglobulinemia de Waldenstrom/mortalidade
12.
Vaccines (Basel) ; 12(7)2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39066448

RESUMO

Molecular surveillance of circulating measles variants serves as a line of evidence for the absence of endemic circulation and provides a means to track chains of transmission. Molecular surveillance for measles (genotyping) is based on the sequence of 450 nucleotides at the end of the nucleoprotein coding region (N450) of the measles genome. Genotyping was established in 1998 and, with over 50,000 sequence submissions to the Measles Nucleotide Surveillance database, has proven to be an effective resource for countries attempting to trace pathways of transmission. This review summarizes the tools used for the molecular surveillance of measles and describes the challenge posed by the decreased number of circulating measles genotypes. The Global Measles and Rubella Laboratory Network addressed this challenge through the development of new tools such as named strains and distinct sequence identifiers that analyze the diversity within the currently circulating genotypes. The advantages and limitations of these approaches are discussed, together with the need to generate additional sequence data including whole genome sequences to ensure the continued utility of strain surveillance for measles.

13.
Eur J Immunol ; 42(6): 1512-22, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22678905

RESUMO

Human blood myeloid DCs can be subdivided into CD1c (BDCA-1)(+) and CD141 (BDCA-3)(+) subsets that display unique gene expression profiles, suggesting specialized functions. CD1c(+) DCs express TLR4 while CD141(+) DCs do not, thus predicting that these two subsets have differential capacities to respond to Escherichia coli. We isolated highly purified CD1c(+) and CD141(+) DCs and compared them to in vitro generated monocyte-derived DCs (MoDCs) following stimulation with whole E. coli. As expected, MoDCs produced high levels of the proinflammatory cytokines TNF, IL-6, and IL-12, were potent inducers of Th1 responses, and processed E. coli-derived Ag. In contrast, CD1c(+) DCs produced only low levels of TNF, IL-6, and IL-12 and instead produced high levels of the anti-inflammatory cytokine IL-10 and regulatory molecules IDO and soluble CD25. Moreover, E. coli-activated CD1c(+) DCs suppressed T-cell proliferation in an IL-10-dependent manner. Contrary to their mouse CD8(+) DC counterparts, human CD141(+) DCs did not phagocytose or process E. coli-derived Ag and failed to secrete cytokines in response to E. coli. These data demonstrate substantial differences in the nature of the response of human blood DC subsets to E. coli.


Assuntos
Antígenos de Superfície/análise , Células Dendríticas/imunologia , Escherichia coli/imunologia , Interleucina-10/biossíntese , Células Mieloides/imunologia , Antígenos CD1 , Células Dendríticas/metabolismo , Glicoproteínas , Humanos , Interleucina-10/metabolismo , Ativação Linfocitária , Fenótipo , Linfócitos T/imunologia , Trombomodulina
14.
J Immunol ; 187(8): 3987-96, 2011 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-21908738

RESUMO

The graft-versus-myeloma (GVM) effect represents a powerful form of immune attack exerted by alloreactive T cells against multiple myeloma cells, which leads to clinical responses in multiple myeloma transplant recipients. Whether myeloma cells are themselves able to induce alloreactive T cells capable of the GVM effect is not defined. Using adoptive transfer of T naive cells into myeloma-bearing mice (established by transplantation of human RPMI8226-TGL myeloma cells into CD122(+) cell-depleted NOD/SCID hosts), we found that myeloma cells induced alloreactive T cells that suppressed myeloma growth and prolonged survival of T cell recipients. Myeloma-induced alloreactive T cells arising in the myeloma-infiltrated bones exerted cytotoxic activity against resident myeloma cells, but limited activity against control myeloma cells obtained from myeloma-bearing mice that did not receive T naive cells. These myeloma-induced alloreactive T cells were derived through multiple CD8(+) T cell divisions and enriched in double-positive (DP) T cells coexpressing the CD8αα and CD4 coreceptors. MHC class I expression on myeloma cells and contact with T cells were required for CD8(+) T cell divisions and DP-T cell development. DP-T cells present in myeloma-infiltrated bones contained a higher proportion of cells expressing cytotoxic mediators IFN-γ and/or perforin compared with single-positive CD8(+) T cells, acquired the capacity to degranulate as measured by CD107 expression, and contributed to an elevated perforin level seen in the myeloma-infiltrated bones. These observations suggest that myeloma-induced alloreactive T cells arising in myeloma-infiltrated bones are enriched with DP-T cells equipped with cytotoxic effector functions that are likely to be involved in the GVM effect.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Efeito Enxerto vs Tumor/imunologia , Mieloma Múltiplo/imunologia , Transferência Adotiva , Animais , Linhagem Celular Tumoral , Separação Celular , Citotoxicidade Imunológica/imunologia , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Transplante Homólogo
15.
J Exp Med ; 203(1): 27-33, 2006 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-16390938

RESUMO

Langerhans cells (LC) and other antigen-presenting cells are believed to be critical in initiating graft versus host responses that influence the outcome of allogeneic hematopoietic stem cell transplantation. However, their fate in humans is poorly understood. We have sought to define the effect of conditioning regimes and graft versus host disease (GVHD) on the survival of recipient LC and reconstitution of donor cells after transplant. Confocal microscopy of epidermal sheets shows that full intensity transplant (FIT) depletes LC more rapidly than reduced intensity transplant (RIT) at day 0, although the nadir is similar in both at 14-21 d. Recovery occurs rapidly within 40 d in the absence of acute GVHD, but is delayed beyond 100 d when GVHD is active. LC chimerism was determined in sex-mismatched transplants using a two-step Giemsa/fluorescence in situ hybridization assay on isolated cells. Acquisition of donor chimerism at 40 d is more rapid after FIT (97%) than RIT (36.5%), irrespective of blood myeloid engraftment. At 100 d, all transplants achieve at least 90% LC donor chimerism and over half achieve 100%. Complete donor chimerism is associated with prior acute cutaneous GVHD, suggesting a role for allogeneic T cells in promoting LC engraftment.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Células de Langerhans , Adulto , Feminino , Doença Enxerto-Hospedeiro , Humanos , Masculino , Pessoa de Meia-Idade , Quimeras de Transplante , Condicionamento Pré-Transplante
16.
Cancer Immunol Immunother ; 61(2): 169-179, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21874303

RESUMO

Immunotherapy is a promising new treatment for patients with advanced prostate and ovarian cancer, but its application is limited by the lack of suitable target antigens that are recognized by CD8+ cytotoxic T lymphocytes (CTL). Human kallikrein 4 (KLK4) is a member of the kallikrein family of serine proteases that is significantly overexpressed in malignant versus healthy prostate and ovarian tissue, making it an attractive target for immunotherapy. We identified a naturally processed, HLA-A*0201-restricted peptide epitope within the signal sequence region of KLK4 that induced CTL responses in vitro in most healthy donors and prostate cancer patients tested. These CTL lysed HLA-A*0201+ KLK4 + cell lines and KLK4 mRNA-transfected monocyte-derived dendritic cells. CTL specific for the HLA-A*0201-restricted KLK4 peptide were more readily expanded to a higher frequency in vitro compared to the known HLA-A*0201-restricted epitopes from prostate cancer antigens; prostate-specific antigen (PSA), prostate-specific membrane antigen (PSMA) and prostatic acid phosphatase (PAP). These data demonstrate that KLK4 is an immunogenic molecule capable of inducing CTL responses and identify it as an attractive target for prostate and ovarian cancer immunotherapy.


Assuntos
Antígenos de Neoplasias/metabolismo , Calicreínas/metabolismo , Fragmentos de Peptídeos/metabolismo , Neoplasias da Próstata/imunologia , Linfócitos T Citotóxicos/metabolismo , Adulto , Idoso , Antígenos de Neoplasias/imunologia , Proliferação de Células , Biologia Computacional , Células Dendríticas/imunologia , Feminino , Antígeno HLA-A2/metabolismo , Humanos , Epitopos Imunodominantes/genética , Calicreínas/imunologia , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/imunologia , Neoplasias da Próstata/patologia , Sinais Direcionadores de Proteínas/genética , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/patologia
17.
Blood ; 116(16): e74-80, 2010 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-20628149

RESUMO

Monocytes and cells of the dendritic cell lineage circulate in blood and eventually migrate into tissue where they further mature and serve various functions, most notably in immune defense. Over recent years these cells have been characterized in detail with the use of cell surface markers and flow cytometry, and subpopulations have been described. The present document proposes a nomenclature for these cells and defines 3 types of monocytes (classical, intermediate, and nonclassical monocytes) and 3 types of dendritic cells (plasmacytoid and 2 types of myeloid dendritic cells) in human and in mouse blood. This classification has been approved by the Nomenclature Committee of the International Union of Immunological Societies, and we are convinced that it will facilitate communication among experts and in the wider scientific community.


Assuntos
Células Sanguíneas/classificação , Células Dendríticas/classificação , Monócitos/classificação , Terminologia como Assunto , Animais , Humanos , Camundongos
18.
Immunology ; 132(2): 296-305, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21091907

RESUMO

Mannose-binding lectin (MBL) is a serum lectin that plays a significant role in innate host defence. Individuals with mutations in exon 1 of the MBL2 gene have reduced MBL ligand binding and complement activation function and increased incidence of infection. We proposed that, during infection, MBL deficiency may impact on dendritic cell (DC) function. We analysed the blood myeloid DC (MDC) surface phenotype, inflammatory cytokine production and antigen-presenting capacity in MBL-deficient (MBL-D) individuals and MBL-sufficient (MBL-S) individuals using whole blood culture supplemented with zymosan (Zy) or MBL-opsonized zymosan (MBL-Zy) as a model of infection. Zy-stimulated MDCs from MBL-D individuals had significantly increased production of interleukin (IL)-6 and tumour necrosis factor (TNF)-α. Stimulation with MBL-Zy significantly decreased IL-6 production by MDCs from MBL-D, but had no effect on TNF-α production. MDCs from both MBL-S and MBL-D individuals up-regulated expression of the activation molecule CD83, and down-regulated expression of homing (CXCR4), adhesion (CD62L, CD49d) and costimulatory (CD40, CD86) molecules in response to Zy and MBL-Zy. MDC from both MBL-D and MBL-S individuals induced proliferation of allogeneic (allo) T cells following Zy or MBL-Zy stimulation; however, MBL-D individuals demonstrated a reduced capacity to induce effector allo-T cells. These data indicate that MBL deficiency is associated with unique functional characteristics of pathogen-stimulated blood MDCs manifested by increased production of IL-6, combined with a poor capacity to induce effector allo-T-cell responses. In MBL-D individuals, these functional features of blood MDCs may influence their ability to mount an immune response.


Assuntos
Apresentação de Antígeno/imunologia , Células Dendríticas/imunologia , Imunidade Inata , Interleucina-6/metabolismo , Lectina de Ligação a Manose/deficiência , Células Mieloides/imunologia , Animais , Diferenciação Celular , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Humanos , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/metabolismo , Camundongos , Células Mieloides/citologia , Células Mieloides/metabolismo , Linfócitos T/citologia , Linfócitos T/imunologia , Zimosan/imunologia , Zimosan/farmacologia
19.
J Hepatol ; 53(4): 599-607, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20667615

RESUMO

BACKGROUND & AIMS: HCV patients who fail conventional interferon-based therapy have limited treatment options. Dendritic cells are central to the priming and development of antigen-specific CD4(+) and CD8(+) T cell immunity, necessary to elicit effective viral clearance. The aim of the study was to investigate the safety and efficacy of vaccination with autologous dendritic cells loaded with HCV-specific cytotoxic T cell epitopes. METHODS: We examined the potential of autologous monocyte-derived dendritic cells (MoDC), presenting HCV-specific HLA A2.1-restricted cytotoxic T cell epitopes, to influence the course of infection in six patients who failed conventional therapy. Dendritic cells were loaded and activated ex vivo with lipopeptides. In this phase 1 dose escalation study, all patients received a standard dose of cells by the intradermal route while sequential patients received an increased dose by the intravenous route. RESULTS: No patient showed a severe adverse reaction although all experienced transient minor side effects. HCV-specific CD8(+) T cell responses were enumerated in PBMC by ELIspot for interferon-gamma. Patients generated de novo responses, not only to peptides presented by the cellular vaccine but also to additional viral epitopes not represented in the lipopeptides, suggestive of epitope spreading. Despite this, no increases in ALT levels were observed. However, the responses were not sustained and failed to influence the viral load, the anti-HCV core antibody response and the level of circulating cytokines. CONCLUSIONS: Immunotherapy using autologous MoDC pulsed with lipopeptides was safe, but was unable to generate sustained responses or alter the outcome of the infection. Alternative dosing regimens or vaccination routes may need to be considered to achieve therapeutic benefit.


Assuntos
Células Dendríticas/imunologia , Hepatite C Crônica/imunologia , Hepatite C Crônica/prevenção & controle , Vacinação , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
20.
Blood ; 112(4): 1184-94, 2008 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-18535206

RESUMO

Activation of human plasmacytoid dendritic cells (pDCs) with ligands for Toll-like receptors (TLRs) 7 and 9 induces the secretion of type I interferons and other inflammatory cytokines as well as pDC differentiation. Transcripts for 2 members of the CD300 gene family, CD300a and CD300c, were identified on pDCs during gene expression studies to identify new immunoregulatory molecules on pDCs. We therefore investigated the expression of CD300a and CD300c and their potential regulation of pDC function. CD300a/c RNA and surface expression were downregulated after stimulation of pDCs with TLR7 and TLR9 ligands. Exogenous interferon (IFN)-alpha down-regulated CD300a/c expression, whereas neutralizing IFN-alpha abolished TLR ligand-induced CD300a/c down-regulation. This implicates IFN-alpha in regulating CD300a/c expression in pDCs. In addition, IFN-alpha favored tumor necrosis factor (TNF)-alpha secretion by CpG-induced pDCs. CD300a/c triggering by cross-linking antibody reduced TNF-alpha and increased IFN-alpha secretion by pDCs. Furthermore, CD300a/c triggering, in the presence of neutralizing IFN-alpha, further reduced TNF-alpha secretion. These data indicate that CD300a and CD300c play an important role in the cross-regulation of TNF-alpha and IFN-alpha secretion from pDCs.


Assuntos
Antígenos CD/fisiologia , Antígenos de Superfície/fisiologia , Células Dendríticas/citologia , Interferon Tipo I/metabolismo , Glicoproteínas de Membrana/fisiologia , Receptores Imunológicos/fisiologia , Receptor 7 Toll-Like/agonistas , Receptor Toll-Like 9/agonistas , Fator de Necrose Tumoral alfa/metabolismo , Antígenos CD/genética , Antígenos de Superfície/genética , Diferenciação Celular , Células Cultivadas , Regulação para Baixo , Perfilação da Expressão Gênica , Humanos , Ligantes , Glicoproteínas de Membrana/genética , RNA Mensageiro/análise , Receptores Imunológicos/genética
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