Distinguishing human peripheral blood CD16 myeloid cells based on phenotypic characteristics.

Myeloid lineage cells present in human peripheral blood include dendritic cells (DC) and monocytes. The DC are identified phenotypically as HLA-DR cells that lack major cell surface lineage markers for T cells (CD3), B cells (CD19, CD20), NK cells (CD56), red blood cells (CD235a), hematopoietic stem cells (CD34), and Mo that express CD14. Both DC and Mo can be phenotypically divided into subsets.

CD300f epitopes are specific targets for acute myeloid leukemia with monocytic differentiation.

Antibody-based therapy in acute myeloid leukemia (AML) has been marred by significant hematologic toxicity due to targeting of both hematopoietic stem and progenitor cells (HSPCs). Achieving greater success with therapeutic antibodies requires careful characterization of the potential target molecules on AML. One potential target is CD300f, which is an immunoregulatory molecule expressed predominantly on myeloid lineage cells.

CD83: Activation Marker for Antigen Presenting Cells and Its Therapeutic Potential.

CD83 is a member of the immunoglobulin (Ig) superfamily and is expressed in membrane bound or soluble forms. Membrane CD83 (mCD83) can be detected on a variety of activated immune cells, although it is most highly and stably expressed by mature dendritic cells (DC). mCD83 regulates maturation, activation and homeostasis.

Examination of CD302 as a potential therapeutic target for acute myeloid leukemia.

Acute myeloid leukemia (AML) is the most common form of adult acute leukemia with ~20,000 new cases yearly. The disease develops in people of all ages, but is more prominent in the elderly, who due to limited treatment options, have poor overall survival rates. Monoclonal antibodies (mAb) targeting specific cell surface molecules have proven to be safe and effective in different haematological malignancies.

The cell surface phenotype of human dendritic cells.

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.

Dendritic cells as cancer therapeutics.

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.

CD83 is a new potential biomarker and therapeutic target for Hodgkin lymphoma.

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.

The Analysis of CD83 Expression on Human Immune Cells Identifies a Unique CD83+-Activated T Cell Population.

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.

CMRF-56(+) blood dendritic cells loaded with mRNA induce effective antigen-specific cytotoxic T-lymphocyte responses.

There are numerous transcriptional, proteomic and functional differences between monocyte-derived dendritic cells (Mo-DC) and primary blood dendritic cells (BDC). The CMRF-56 monoclonal antibody (mAb) recognizes a cell surface marker, which is upregulated on BDC following overnight culture. Given its unique ability to select a heterogeneous population of BDC, we engineered a human chimeric (h)CMRF-56 IgG4 mAb to isolate primary BDC for potential therapeutic vaccination.

A multi-laboratory comparison of blood dendritic cell populations.

HLDA10 collated a panel of monoclonal antibodies (mAbs) that primarily recognised molecules on human myeloid cell and dendritic cell (DC) populations. As part of the studies, we validated a backbone of mAbs to delineate monocyte and DC populations from peripheral blood. The mAb backbone allowed identification of monocyte and DC subsets using fluorochromes that were compatible with most 'off the shelf' or routine flow cytometers.

New insights into the phenotype of human dendritic cell populations.

HLDA10 is the Tenth Human Leukocyte Differentiation Antigen (HLDA) Workshop. The HLDA Workshops provide a mechanism to allocate cluster of differentiation (CD) nomenclature by engaging in interlaboratory studies. As the host laboratory, we invited researchers from national and international academic and commercial institutions to submit monoclonal antibodies (mAbs) to human leukocyte surface membrane molecules, particularly those that recognised molecules on human myeloid cell populations and dendritic cells (DCs).

A phase I clinical trial of CD1c (BDCA-1)+ dendritic cells pulsed with HLA-A*0201 peptides for immunotherapy of metastatic hormone refractory prostate cancer.

Preclinical studies have suggested that purified populations of CD1c (BDCA-1) blood-derived dendritic cells (BDC) loaded with tumor-specific peptides may be a feasible option for prostate cancer immunotherapy. We performed an open-label dose-finding Phase I study to evaluate the safe use of CD1c BDC in patients with advanced metastatic hormone refractory prostate cancer. HLA-A*0201-positive patients with advanced metastatic prostate cancer were recruited and consented.

Antibody therapy for acute myeloid leukaemia.

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.

Alterations in chemokine receptor CCR5 expression on blood dendritic cells correlate with acute graft-versus-host disease.

Background: Dendritic 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.

Methods: We performed flow cytometry to document the expression of chemokine receptors on circulating DC and correlated the findings after alloHCT with occurrence of acute GVHD.

CD300 molecule regulation of human dendritic cell functions.

Dendritic cells (DC) are a heterogeneous population of leucocytes which play a key role in initiating and modulating immune responses. The human CD300 family consists of six immunoregulatory leucocyte membrane molecules that regulate cellular activity including differentiation, viability, cytokine and chemokine secretion, phagocytosis and chemotaxis. Recent work has identified polar lipids as probable ligands for these molecules in keeping with the known evolutionary conservation of this family.

Human CD1c (BDCA-1)+ myeloid dendritic cells secrete IL-10 and display an immuno-regulatory phenotype and function in response to Escherichia coli.

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.

Myeloma-induced alloreactive T cells arising in myeloma-infiltrated bones include double-positive CD8+CD4+ T cells: evidence from myeloma-bearing mouse model.

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.

Cellular therapy to treat haematological and other malignancies: progress and pitfalls.

The recent Food and Drug Administration (FDA) approval of a cellular therapy to treat castration resistant prostate cancer has reinforced the potential of cellular therapy to consolidate current pharmacological approaches to treating cancer. The emergence of the cell manufacturing facility to facilitate clinical translation of these new methodologies allows greater access to these novel therapies. Here we review different strategies currently being explored to treat haematological malignancies with a focus on adoptive allogeneic or autologous transfer of antigen specific T cells, NK cells or dendritic cells.

Human kallikrein 4 signal peptide induces cytotoxic T cell responses in healthy donors and prostate cancer patients.

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.

Mannose-binding lectin deficiency influences innate and antigen-presenting functions of blood myeloid dendritic cells.

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.

Screening of the HLDA9 panel on peripheral blood dendritic cell populations.

Dendritic cells (DC) are a heterogeneous population of bone marrow derived leucocytes that are essential in the initiation of primary T lymphocyte responses. DC are identified as Lineage negative, HLA-DR(+) blood cells that can be further subdivided by CD11c to distinguish CD11c(+) DC and the CD11c(-) plasmacytoid DC. Plasmacytoid DC are the primary IFNα producing cells and express CD303, CD304 and CD123.

Mesenchymal stromal cells transiently alter the inflammatory milieu post-transplant to delay graft-versus-host disease.

Background: Multipotent mesenchymal stromal cells suppress T-cell function in vitro, a property that has underpinned their use in treating clinical steroid-refractory graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. However the potential of mesenchymal stromal cells to resolve graft-versus-host disease is confounded by a paucity of pre-clinical data delineating their immunomodulatory effects in vivo.

Design And Methods: We examined the influence of timing and dose of donor-derived mesenchymal stromal cells on the kinetics of graft-versus-host disease in two murine models of graft-versus-host disease (major histocompatibility complex-mismatched: UBI-GFP/BL6 [H-2(b)]→BALB/c [H-2(d)] and the sibling transplant mimic, UBI-GFP/BL6 [H-2(b)]→BALB.

Human CD141+ (BDCA-3)+ dendritic cells (DCs) represent a unique myeloid DC subset that cross-presents necrotic cell antigens.

The characterization of human dendritic cell (DC) subsets is essential for the design of new vaccines. We report the first detailed functional analysis of the human CD141+ DC subset. CD141+ DCs are found in human lymph nodes, bone marrow, tonsil, and blood, and the latter proved to be the best source of highly purified cells for functional analysis.

Isolation of human blood DC subtypes.

Human blood dendritic cells (DCs) are a rare, heterogeneous cell population that comprise approximately 1% of circulating peripheral blood mononuclear cells (PBMCs). Their isolation has been confounded by their scarcity and lack of distinguishing markers and their characterisation perplexed by the recent discovery of phenotypic and functionally distinct subsets. Human blood DCs are broadly defined as leukocytes that are HLA-DR positive and lack expression of markers specific for T cell, B cell, NK cell, monocyte and granulocyte lineages.