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Biomedical subjects

K McGinnes

Publications and source records attributed to K McGinnes.

10 recordsLinked to original sources
PubMed1993

Mononuclear cell subpopulations and cytokine levels in human visceral leishmaniasis before and after chemotherapy.

Serum cytokine levels and mononuclear cell subpopulations in the spleen and peripheral blood of patients with visceral leishmaniasis before and after antimony therapy were analyzed. The percentages of activated monocytes/macrophages, T cells, and possibly B cells; of gamma/delta T cell receptor (TCR)-bearing T cells; of CD4- CD8- alpha/beta TCR-bearing T cells; and serum levels of tumor necrosis factor-alpha (TNF alpha), interferon-gamma (IFN-gamma), and interleukin-6 (IL-6) were high in patients with active visceral leishmaniasis. The proportion of both helper and suppressor CD4+ cells and of cells with NK and cytotoxic T phenotypes were depressed. Successful chemotherapy normalized these parameters with the exception of activated monocytes. Thus, the impaired cell-mediated immunity in human Leishmania donovani infection is primarily due to a decrease in the proportion and possibly the activity of helper CD4+ cells, while suppressor cells do not seem to play a relevant role. TNF alpha, IL-6, and IFN-gamma may prove to be useful markers for monitoring response to therapy.

Adolescent↗
PubMed1991

B-lineage colonies from normal, human bone marrow are initiated by B cells and their progenitors.

We have recently described a reproducible method whereby colonies containing cells that secrete immunoglobulin (Ig) can be grown from normal, human, adult bone marrow samples. The present report characterizes the cells that initiate these colonies. It is shown that all clonogenic cells express the CD19 surface antigen, as removal of these cells before plating in the B-cell colony assay abolished the subsequent growth of plaque-forming, B-lineage colonies. Cells from both the CD10+ and CD20+ B-lineage subpopulations initiated the growth of B-cell colonies, as removal of either subset resulted in a 50% reduction in the number of resulting B-cell colonies. The removal of activated B cells (CD23+), plasma cells (PCA-1+), or myeloid cells (CD13+) did not lead to a significant depletion in B-cell colony formation. Pre-B cells that were not yet committed to Ig light chain expression were also able to differentiate and proliferate into Ig-secreting colonies under the culture conditions used. Colonies initiated by these light chain uncommitted cells were distinguished using a replicate protein immunoblotting technique, which detects the simultaneous secretion of Ig kappa and Ig lambda from single colonies. These experiments provide evidence that the CD10 antigen is expressed on B-lineage cells before Ig light chain commitment, whereas CD20 is not. In conclusion, this B-cell colony assay provides a system for studying the differentiation of bone marrow-derived B cells and their precursors into Ig-secreting cells.

Antibodies, Monoclonal↗
PubMed1991

Interleukins 1, 4 and 6 induce the colony formation of human bone marrow B lineage cells.

An agar-based, B cell colony assay (McGinnes, K. et al., Blood 1990. 76:896) has been used to study the influence of known cytokines on the growth of B lineage colonies initiated by cells from normal, human bone marrow samples. We demonstrate that a combination of interleukin (IL) 1, IL4 and IL6 act directly to promote the generation of plaque-forming colonies. IL6 was shown to act at a late stage of colony formation, which is consistent with its role in the induction of immunoglobulin secretion from mature B cells. In contrast, IL 1 and IL 4 were required at earlier stages in the formation of colonies containing cells which secrete immunoglobulin.

B-Lymphocytes↗
PubMed1991

Human B-lymphopoiesis is supported by bone marrow-derived stromal cells.

We have recently reported an in vitro culture system that allows the clonal growth and differentiation of normal human bone marrow B-lineage cells. In the report presented here, we have used this B-cell colony assay to study the influence of cellular components of the human bone marrow microenvironment on B-lymphopoiesis. It is demonstrated that bone marrow stromal cells were able to provide all the necessary requirements for the growth and differentiation of B-lineage cells under the conditions of the B-cell colony assay. These stromal cells were obtained from long-term bone marrow cultures (LTBMC) that had been established from the spicules in human bone marrow. When these stromal cells were plated as an adherent underlayer in the double-agar B-cell colony assay, both immature and mature B-lineage cells were induced to differentiate into colonies containing cells that secreted immunoglobulin. The stromal cells from these spicule-derived LTBMCs maintained the capacity to support B-cell colony formation for up to 9 months.

Antigens, CD↗
PubMed1990

Growth and detection of human bone marrow B-lineage colonies.

A reproducible method for growing normal human bone marrow B-lineage colonies in agar is described. The clonogenic cells require a rich medium, Opti-MEM (GIBCO/BRL, Burlington, Ontario, Canada), and a source of T-cell-derived factors for growth. The conditions described appear to be limiting for the colony progenitor, suggesting assay clonality. Three novel methods that permit routine and rapid detection of these human B-cell colonies are also described. Colonies containing cells that secrete immunoglobulin are detected by plaquing and protein immunoblotting, while RNA transcripts can be detected by RNA colony blotting. The detection of more than one secreted immunoglobulin isotype or RNA species in a single colony can also be achieved. This B-cell colony assay and the associated detection methods will allow the further delineation of human B lymphopoiesis in both normal and disease states.

B-Lymphocytes↗
PubMed1988

Effects of interferon on natural killer (NK) cells assessed by fluorescent probes and flow cytometry.

The effects of interferon-alpha and -gamma (IFN) on natural killer (NK) cells was investigated by labelling cells with fluorescent membrane and intracellular probes and analysing these by flow cytometry. Peripheral blood mononuclear cells (PBMCs), sorted NK cells and non-NK cells were labelled with one of the fluorescent probes, 3,3'-dihexyloxacarbocyanine (DiOC6(3], N-phenyl-1-naphthylamine (NPN) or Quin 2, subsequent to incubation with IFN-alpha or IFN-gamma and the change in their fluorescence was monitored by flow cytometry. NK activity after treatment with IFN-alpha or -gamma was also monitored in parallel using a standard 51Cr-release assay. IFN-alpha treatment of PBMCs caused an apparent depolarisation and subsequent hyperpolarization of the cell membranes. Such changes reflect movement of ions across the cell membrane and also the binding of IFN-alpha to the cell surface receptor. Molecular conformational changes in the cell membrane due to IFN-alpha and IFN-gamma were monitored by labelling cell populations with NPN. Changes in NPN-labelled cell fluorescence intensity, indicating changes in membrane conformation, were greatest in NK cell populations activated by IFN-gamma. IFN-alpha had a more profound effect on non-NK cell populations. The concentration of free intracellular Ca2+ ions is also affected by IFN-alpha and IFN-gamma activation, as monitored by the fluorescent probe, Quin 2. There is an apparent decrease in intracellular Ca2+ ion concentration in the NK cell population when treated with IFNs, with the greatest effect being shown by IFN-gamma. These data indicate that the effects of IFNs on NK cells can be monitored at a cellular level using fluorescent probes and flow cytometry. As analysed by these probes, IFN-alpha and IFN-gamma appear to affect NK cells via different mechanisms.

1-Naphthylamine↗
PubMed1988

Effect of interferon on the in vitro synthesis of paraprotein by plasma cells in myeloma.

The aim of this study was to determine the effects of interferon on in vitro immunoglobulin synthesis by the plasma cells of patients with multiple myeloma. Bone marrow cultures were set up in the presence of media alone or alpha-interferon. Supernatants were harvested over a 24-hour period and assayed for paraprotein immunoglobulin synthesis using radio-immunoassays developed in this department. The 24-hour paraprotein synthesis ranged from 9 to 493 micrograms/10(6) plasma cells in patients with IgG myeloma (n = 11), and from 0.3 to 8.3 micrograms/10(6) plasma cells in those with IgA (n = 4). Alpha-Interferon had variable effects on paraprotein synthesis in IgG myelomas, causing an inhibition of synthesis (up to 61%) in 3 patients and an enhancement of synthesis (up to 95%) in 5 cases. In IgA myelomas, on the other hand, alpha-interferon caused inhibition of synthesis in 1 case. In the 2 patients studied during alpha-interferon administration, IgG synthesis was significantly reduced. More cases are currently being investigated. Clearly, immunoglobulin synthesis by plasma cells shows variable modulation by alpha-interferon in vitro.

Adult↗
PubMed1987

The effect of radiotherapy on the natural killer (NK)-cell activity of cancer patients.

The aim of this study was to determine the effect of radiotherapy on peripheral blood natural killer (NK)-cell number and activity in 15 patients with cancer, prior to the commencement and at the completion of radiotherapy. The following observations were made. Prior to radiotherapy NK activity could not be correlated with the stage of malignancy. In all patients with advanced disease and with subnormal baseline NK activity, the outcome of radiotherapy was unfavorable. Following radiotherapy to sites including the mediastinum, patients had decreased NK activity compared with those receiving treatment to other sites. This decrease was not related to the dose of radiotherapy or stage of malignancy. The tumor response was favorable in most patients whose NK activity decreased as a result of radiotherapy. The decrease in NK activity may be associated with a decrease in the percentage of NK (N901) cells in the peripheral blood. The reduction in NK activity in those patients receiving mediastinal irradiation may be due to the large volume of blood which transits the field, so that the NK cells, or their more radiosensitive precursors, may be damaged and/or differentiation inhibited. Thus, these new observations show that radiotherapy does indeed affect the NK activity in cancer patients predominantly when the irradiation site includes the mediastinum.

Adult↗
PubMed1986

A fluorescence NK assay using flow cytometry.

A flow cytometric NK assay was developed in which the K562 targets were labelled with the fluorogenic substrate, carboxyfluorescein diacetate (c'FDA). This new assay compared favourably with results obtained using the conventional 51Cr-release assay. c'FDA was not toxic to target cells and did not inhibit lysis. The assay permits the evaluation of various aspects of NK activity such as the activity of NK-enriched, IFN-alpha-activated, and ALG-inhibited populations. The assay can be used in place of 51Cr-release, and has the advantages of being able to directly monitor target cell lysis of reducing overall assay time, and the avoidance of radioisotope usage.

Adult↗