DEC-205 (CD205) belongs to the macrophage mannose receptor family of C-type lectin endocytic receptors and behaves as an antigen uptake/processing receptor for dendritic cells (DC). To investigate ...DEC-205 tissue distribution in human leukocytes, we generated a series of anti-human DEC-205 monoclonal antibodies (MMRI-5, 6 and 7), which recognized epitopes within the C-type lectin-like domains 1 and 2, and the MMRI-7 immunoprecipitated a single ∼200 kDa band, identified as DEC-205 by mass spectrometry. MMRI-7 and another DEC-205 mAb (MG38), which recognized the epitope within the DEC-205 cysteine-rich and fibronectin type II domain, were used to examine DEC-205 expression by human leukocytes. Unlike mouse DEC-205, which is reported to have predominant expression on DC, human DEC-205 was detected by flow cytometry at relatively high levels on myeloid blood DC and monocytes, at moderate levels on B lymphocytes and at low levels on NK cells, plasmacytoid blood DC and T lymphocytes. MMRI-7 F(ab′)2 also labeled monocytes, B lymphocytes and NK cells similarly excluding reactivity due to non-specific binding of the mAb to FcγR. Tonsil mononuclear cells showed a similar distribution of DEC-205 staining on the leukocytes. DEC-205-specific semiquantitative immunoprecipitation/western blot and quantitative reverse transcriptase-PCR analysis established that these leukocyte populations expressed DEC-205 protein and the cognate mRNA. Thus, human DEC-205 is expressed on more leukocyte populations than that were previously assumed based on mouse DEC-205 tissue localization studies. The broader DEC-205 tissue expression in man is relevant to clinical DC targeting strategies and DEC-205 functional studies.
Only modest advances in AML therapy have occurred in the past decade and relapse due to residual disease remains the major challenge. The potential of the immune system to address this is evident in ...the success of allogeneic transplantation, however this leads to considerable morbidity. Dendritic cell (DC) vaccination can generate leukemia-specific autologous immunity with little toxicity. Promising results have been achieved with vaccines developed in vitro from purified monocytes (Mo-DC). We now demonstrate that blood DC (BDC) have superior function to Mo-DC. Whilst BDC are reduced at diagnosis in AML, they recover following chemotherapy and allogeneic transplantation, can be purified using CMRF-56 antibody technology, and can stimulate functional T cell responses. While most AML patients in remission had a relatively normal T cell landscape, those who had received fludarabine as salvage therapy have persistent T cell abnormalities including reduced number, altered subset distribution, failure to expand, and increased activation-induced cell death. Furthermore, PD-1 and TIM-3 are increased on CD4T cells in AML patients in remission and their blockade enhances the expansion of leukemia-specific T cells. This confirms the feasibility of a BDC vaccine to consolidate remission in AML and suggests it should be tested in conjunction with checkpoint blockade.
Objectives
Effective antibody–drug conjugates (ADCs) provide potent targeted cancer therapies. CD83 is expressed on activated immune cells including B cells and is a therapeutic target for Hodgkin ...lymphoma. Our objective was to determine CD83 expression on non‐Hodgkin lymphoma (NHL) and its therapeutic potential to treat mantle cell lymphoma (MCL) which is currently an incurable NHL.
Methods
We analysed CD83 expression on MCL cell lines and the lymph node/bone marrow biopsies of MCL patients. We tested the killing effect of CD83 ADC in vitro and in an in vivo xenograft MCL mouse model.
Results
CD83 is expressed on MCL, and its upregulation is correlated with the nuclear factor κB (NF‐κB) activation. CD83 ADC kills MCL in vitro and in vivo. Doxorubicin and cyclophosphamide (CP), which are included in the current treatment regimen for MCL, enhance the NF‐κB activity and increase CD83 expression on MCL cell lines. The combination of CD83 ADC with doxorubicin and CP has synergistic killing effect of MCL.
Conclusion
This study provides evidence that a novel immunotherapeutic agent CD83 ADC, in combination with chemotherapy, has the potential to enhance the efficacy of current treatments for MCL.
Mantle cell lymphoma (MCL) is a blood cell cancer with high mortality. We identified CD83 as a potential therapeutic target. Anti‐CD83 antibody toxin conjugate kills MCL. The combination of chemotherapy with anti‐CD83 antibody could enhance the therapeutic efficacy.
Antibody therapy for acute myeloid leukaemia Gasiorowski, Robin E.; Clark, Georgina J.; Bradstock, Kenneth ...
British journal of haematology,
February 2014, Letnik:
164, Številka:
4
Journal Article
Recenzirano
Summary
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.
The CD300 glycoproteins are a family of cell surface molecules that modulate a diverse array of cell processes via their paired triggering and inhibitory receptor functions. Family members share a ...common evolutionary pathway and at least one member of the family has undergone significant positive selection, indicating their crucial value to the host. This review clarifies the occasionally confusing usage of nomenclature for the CD300 family and summarizes our current understanding of their genomics, expression and function. Their ability to fine tune leukocyte function and immune responses highlights several potential options to exploit the CD300 molecules as therapeutic targets in chronic inflammatory diseases, allergy and other disease states.
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.
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.
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 CD2hi and CD2lo pDCs represent discontinuous subsets, each with hallmark pDC functionality, including interferon‐alpha production. The rarer CD2hi pDC subset demonstrated a significant survival advantage over CD2lo 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 CD2hi pDC in multiple myeloma patients treated with GCs. Hence, the selective apoptosis of CD2lo pDC during stress represents a novel mechanism for the control of innate responses.
BACKGROUNDDendritic cells (DC) are important in the development of acute graft-versus-host disease (GVHD) after allogeneic hemopoietic cell transplantation (alloHCT). The trafficking of immature DC ...from blood to GVHD target organs is likely to be regulated by chemokine receptors.
METHODSWe performed flow cytometry to document the expression of chemokine receptors on circulating DC and correlated the findings after alloHCT with occurrence of acute GVHD.
RESULTSIn normal individuals, plasmacytoid DC (pDC) expressed high levels of CCR5, whereas the major CD16 myeloid DC subpopulation lacked CCR5. However, its expression on CD16 cells was induced by culture in allogeneic mixed lymphocyte reaction supernatant, an effect largely mediated by interferon-γ. CCR5 was expressed on a significant proportion of CD16 DC in 42 alloHCT patients, whereas it was down-regulated on pDC. The maximum percentage of CCR5CD16 DC, at any time after transplantation, correlated with acute GVHD, whereas the minimum CCR5 on pDC showed a similar correlation. Before developing signs of GVHD, the maximum percentage CCR5CD16 DC was higher in patients with GVHD grades II to IV than in GVHD grades 0 and I, whereas the minimum percentage CCR5 on pDC was lower in GVHD grades II to IV than in GVHD grades 0 and I. CCR5 levels more than 20.5% on CD16 myeloid DC and less than 22.6% on CD123 pDC correlated with subsequent GVHD grades II to IV with high sensitivities and specificities.
CONCLUSIONSThese observations may reflect DC activation and altered homing during the alloimmune response and could allow early diagnosis and therapeutic intervention before the clinical diagnosis of GVHD.
BACKGROUNDThe majority of clinical allogeneic haemopoietic cell transplants (alloHCT) are currently performed using reduced intensity conditioning (RIC) instead of myeloablative conditioning (MAC). ...However, most of the murine models for alloHCT and ensuing complications such as Graft versus Host Disease (GVHD) are studied with MAC models while the biology underlying RIC treatment remains incompletely understood.
METHODSWe investigated a new murine model of major histocompatibility complex (MHC)-matched multiple minor histocompatibility antigen mismatched alloHCT, using 10 x 106 bone marrow (BM) cells and 10-15 x 106 splenocytes from C57BL6 (H-2b) donor mice transplanted into BALB.B (H-2b) recipients after optimizing a RIC protocol consisting of 100mg/kg/day fludarabine for 5 days, 60mg/kg/day cyclophosphamide for 2 days, and sub-lethal total body irradiation (TBI). The MAC model consisted of cyclophosphamide 60mg/kg/day for 2 days and TBI of 850cGy. Mice were scored daily for severity of GVHD for 100 days post-transplant. In other groups of mice, tissue samples from RIC alloHCT mice were collected at different time points to assess the pathological and immunological features of GVHD compared to syngeneic RIC or allogeneic MAC transplant models.
RESULTSThe lowest TBI dose capable of achieving complete donor chimerism with cyclophosphamide and fludarabine treatment in this strain combination was 325cGy. Mice given RIC had a reduced incidence and delayed onset of GVHD and significantly prolonged survival compared to MAC transplanted recipients. Similar to the MAC model, GVHD associated with RIC showed lymphocytic infiltration of portal tracts and damages bile ducts in liver. Gut pathology was less pronounced in RIC GVHD. In contrast, RIC mice with GVHD showed evidence of BM suppression, with anemia, reduced BM cellularity, and profound reduction in BM B cell lymphopoiesis, associated with damage to the endosteal BM niche. This was associated with an increase in BM CD8+ effector T cells in RIC mice, and elevated blood and BM plasma levels of Th1 cytokines. Increasing doses of splenocytes resulted in increased incidence of GVHD in RIC mice, which was dependent on donor CD8+ and CD4+ effector T cells. We have followed the upregulation of activation markers on donor and recipient dendritic cell and T cell populations in spleen and lymph nodes over time after RIC and MAC alloHCT to compare how the conditioning regimes contribute to immune activation.
CONCLUSIONWe demonstrate that the BM is a major target organ of GVHD driven by CD8+ and CD4+ effector T cells in an informative, clinically relevant, RIC alloHCT mouse model.
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