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Biomedical subjects

J L McKenzie

Publications and source records attributed to J L McKenzie.

At least 19 recordsLinked to original sources
PubMed1992

Adhesion molecules on human tonsil dendritic cells.

Dendritic cells are specialist antigen-presenting cells that have a unique ability to stimulate a primary T cell response. Activation of T cells by DC depends on the formation of cell clusters creating DC-T cell membrane contact that probably involves adhesion molecules. Monoclonal antibodies were used to study adhesion molecules on DC, including members of the integrin and immunoglobulin supergene families. DC expressed LFA-1, ICAM-1, LFA-3, and the Hermes antigen, but no other integrin or immunoglobulin supergene family adhesion molecules were detected using a sensitive immunoperoxidase staining technique. Monoclonal antibodies to LFA-1 alpha and LFA-1 beta inhibited DC-stimulated allogeneic T cell (MLR) responses by 75 +/- 12% and 74 +/- 8%, respectively, as did the anti-LFA-3 (56 +/- 3% inhibition) and anti-LFA-2 (60 +/- 5% inhibition) antibodies. Three different anti-ICAM-1 antibodies inhibited only to a limited degree (mean range 8-24%). The inhibitory effect of the LFA-1 and LFA-3 antibodies was maximal if added early to the MLR. The inhibitory effect of the different antibodies was associated with variable decreases in DC-T cell cluster stability. The simultaneous addition of monoclonal antibodies to MLRs and preincubation washing experiments established that DC have at least 3 independent adhesion ligand interactions (LFA-1-ICAM-1, ICAM-1-LFA-1, and LFA-3-CD2) with T cells. It seems likely that the additional ligand for LFA-1, ICAM-2, is expressed on DC and contributes significantly to DC-T cell adherence and T cell activation. The membrane mobility of these molecules may also be important in the DC-T cell activation process.

Antibodies↗
PubMed1992

Hodgkin's disease cell lines: a model for interleukin-1-independent accessory cell function.

The haemopoietic origins of the Hodgkin's disease (HD)-derived cell lines L428, KM-H2 and HDLM-2 remain controversial. Analysis of T-cell receptor (TcR) and Ig rearrangements cannot resolve this, and lineage promiscuity limits the interpretation of isolated surface antigen expression. Nonetheless the cell marker profile of L428 has similarities with human dendritic cells (DC), and L428 strongly stimulates in the mixed leucocyte reaction (MLR). We therefore undertook an extended immunophenotypic comparison of the HD lines with that recently defined for DC, prior to examining their ability to stimulate allogenic T lymphocytes, and comparing the molecular interactions involved with those of primary MLR stimulatory cells. The immunophenotype of the HD lines failed to establish either a lymphoid or monocytoid derivation. The profile of L428 appeared similar to the human DC. All three lines were potent stimulators in the primary MLR, and each expressed relevant adhesion and signal-transducing molecules important for co-stimulating T lymphocytes. Inhibition studies using monoclonal antibodies indicated similar contributions within HD line-T cell MLR to that documented in human tonsil DC-T cell MLR. The HD lines produced no detectable interleukin-1 (IL-1) by biological or immunological analysis. Moreover they stimulated allogeneic T lymphocytes in the presence of anti-IL-1 antibodies. Thus although IL-1 mRNA can be detected in both HDLM-2 and KM-H2 by polymerase chain reaction, these lines, and L428, share with DC the ability to stimulate allogeneic T lymphocytes in an IL-1-independent manner [corrected]. HD lines, particularly L428, may provide a standardized, reproducible, IL-1-independent model for dissection of the co-stimulatory requirements of the human primary MLR.

Antigens, CD↗
PubMed1990

Synthesis and alpha 2-adrenoceptor effects of substituted catecholimidazoline and catecholimidazole analogues in human platelets.

It is known that the steric requirements for the interactions of catecholamines and catecholimidazolines with alpha 1- and alpha 2-adrenoceptors are different. New analogues of desoxycatecholimidazoline (1), desoxycatecholimidazole (3), benzylic hydroxyl substituted imidazole (4), and the aromatic fluorine substitution analogues of 1 at the 2 (5), 5 (6), and 6 (7) positions, and a set of asymmetric 4-substituted catecholimidazolines, S-8 and R-8, were prepared and tested for interaction with alpha 2-adrenoceptors in human platelets. With the exception of 3, all compounds were selective for alpha-adrenoceptor-mediated responses in human platelets. Introduction of a double bond in imidazoline 1 to give an imidazole 3 or the introduction of a benzylic hydroxyl group to 3, as in 4, reduced the inhibition of platelet aggregation with a rank order potency of 1 greater than 3 greater than 4. Fluorine atom substitution at the 2-, 5-, or 6-positions only slightly modified the inhibitory activity of 1. Each analogue (1, 3-7) produced alpha 2-mediated inhibition of platelet adenylate cyclase and can be classified as a partial agonist. The inhibition potency of S-8 and R-8 against epinephrine-induced aggregatory responses were greatly different, and only R-8 and 4 were alpha 2-agonists on human platelet function. Our studies provide further evidence for the differential interaction of catecholamines and catecholimidazolines in alpha 1- and alpha 2-adrenoceptor systems.

Blood Platelets↗
PubMed1990

Interstitial dendritic cells.

Interstitial dendritic cells (IDC) were first identified in the interstitium of non-lymphoid organs as leucocytes which stained intensely with anti-MHC class II antibodies. These cells have been identified in several species including man, and can be distinguished from tissue macrophages by their immunological phenotype and cytochemical and functional characteristics. IDC appear to be closely related to lymphoid dendritic cells (DC), and have the capacity to bind antigen and stimulate T lymphocyte responses. It seems probable that they represent a stage of nonlymphoid dendritic cell differentiation necessary for antigen surveillance, similar to the Langerhans cell of the skin. Exposure to antigen appears to induce migration of these cells into adjacent lymphatics and subsequent localization in the interfollicular areas of lymph node, where the DC present processed antigen to activate a primary T cell response. The IDC has been identified as the passenger leucocyte within organ allografts which contributes substantially to graft immunogenicity, so that eradication of donor organ IDC improves organ graft survival.

Animals↗
PubMed1989

An activation antigen on a subpopulation of B lymphocytes identified by the monoclonal antibody CMRF-17.

The identification of membrane molecules expressed on subpopulations of B lymphocytes is of potential significance because these molecules may be candidates for regulating the activation, proliferation and differentiation of B cells. A new monoclonal antibody, CMRF-17, which reacts with a subpopulation of tonsil B lymphocytes has been produced. The antibody did not react with T lymphocytes in tonsil or peripheral blood nor most peripheral blood B lymphocytes but did label erythrocytes and some platelets. In tonsil, the germinal centre cells, cells in the interfollicular region and endothelial cells were positive, but mantle zone B cells were negative. Double labelling experiments showed that CMRF-17 reacted with activated tonsillar lymphocytes. The antigen recognized by CMRF-17 was heat stable, resistant to treatment with proteolytic enzymes and neuraminidase and was shown to be a carbohydrate determinant on one or more glycolipids. These characteristics of the antigen recognized by CMRF-17 and its pattern of reactivity distinguish this antibody from other monoclonal antibodies recognizing B-cell activation markers. It was notable that of the B-lymphoid malignancies tested to date, including those of probable follicular origin, few stained with CMRF-17.

Antibodies, Monoclonal↗
PubMed1989

Human dendritic cells stimulate allogeneic T cells in the absence of IL-1.

Dendritic cells (DC), which express high-density HLA class II molecules, stimulate strong primary allogeneic T-cell responses via an interaction of the T-cell receptor with major histocompatibility complex (MHC) antigens (signal 1). It is not yet clear whether they also provide a second stimulus to the responding T cell in the form of the cytokine interleukin-1 (IL-1). To clarify this point, the ability of purified human tonsil DC to produce IL-1 and to stimulate allogeneic T cells was tested. No intracellular IL-1 alpha or beta was identified in DC comparable to that readily demonstrated in monocytes, and IL-1 release from lipopolysaccharide (LPS)-stimulated DC was not detected in either a biological assay for IL-1 or an ELISA assay for IL-1 beta. Furthermore, strong stimulation of allogeneic T lymphocytes by DC in the mixed leucocyte reaction (MLR) was noted to occur in the absence of IL-1 production, and this stimulation was not inhibited by polyclonal antisera to IL-1 alpha and IL-1 beta, which were known to inhibit IL-1-mediated thymocyte proliferation. Other HLA-class II-positive cell populations, namely peripheral blood monocytes and B cells, purified by methods which avoided DC contamination, were unable to stimulate allogeneic T cells with or without supplementary IL-1. We conclude that DC are very effective stimulators of T lymphocytes and that IL-1 is not required as a second signal for allogeneic T-cell responses.

Antibodies, Monoclonal↗
PubMed1988

Isolation and characterization of human tonsil dendritic cells.

Human dendritic cells were isolated from tonsils by density gradient separation followed by FACS IV sorting with mAbs to remove contaminating cell populations. The resulting dendritic cell population consisted of large cells with plentiful basophilic cytoplasm, lacking in granules but containing a prominent Golgi apparatus and numerous mitochondria. The cell membrane was irregular, and marked cell protrusions were obvious when stained with anti-HLA class II reagents. Their nuclei were irregular and often indented with a visible nucleolus. These cells were not phagocytic and stimulated autologous and allogeneic lymphocytes more effectively than other tonsil cell types in MLR. Phenotypic analysis of these cells confirmed that they expressed the leucocyte common antigen and stained strongly for HLA-class II antigens. Tonsil dendritic cells also coexpressed the LFA-1 alpha and LFA-1 beta chains but did not stain with a wide variety of anti-monocyte or anti-macrophage antibodies. The cells also lacked Fc and complement receptors and failed to stain with CD1 antibodies. Extensive testing with mAbs revealed only a few positive reactions, and these were consistent with reports of these antibodies staining interdigitating cells in tissue sections. This established that tonsil dendritic cells belong to the unique haemopoietic cell lineage of dendritic cells. No cytoplasmic staining of IL-1 alpha or IL-1 beta was demonstrated, although these lymphokines were readily detected in activated monocytes.

Antibodies, Monoclonal↗
PubMed1988

Characterization of interstitial dendritic cells in human liver.

Sensitive immunofluorescence and immunoperoxidase techniques were used to test an extensive range of monoclonal antibodies for reactivity with Kupffer cells and interstitial dendritic cells (DCs) in cryostat-cut sections of human liver. Leucocytes with a dendritic cell morphology were identified with CD45 (antileucocyte common) reagents in portal tracts, predominantly around bile ducts, and these cells stained strongly for the HLA-DP, DQ, and DR antigens. Kupffer cells stained less intensely with anti-class-II reagents, particularly anti-HLA-DQ. The interstitial DCs expressed the LFA-1 antigen but failed to stain with CD11b, CD11c, and the defined T and B cell CD antibodies; nor did they stain with antibodies to FcR1, FcR11, FcRIII, or the C3b receptor. Of the myeloid monoclonal antibodies available from the 3rd Leucocyte Differentiation Antigen Workshop, only Y2/131, Ki-M7, Ki-M8, and a minority of CD14 antibodies stained DCs, whereas Kupffer cells showed a wider reactivity with antimacrophage antibodies including those of workshop groups 11, 15, 16, and other unique antibodies. A 2nd probable DC population was identified in the liver capsule that had a similar phenotype to portal interstitial DCs. Although some minor phenotypic differences between liver portal DCs and the phenotypes of Langerhans cells and isolated tonsil DCs were noted, our results support the view that there is a unique hemopoietic lineage of DCs. The presence of DCs, which stimulate strong allogeneic T cell responses, in the portal triads is consistent with the fact that the histologic changes of graft-versus-host disease seen in bone marrow transplantation and the lymphocytic infiltrate in a rejecting liver allograft occur predominantly in the periportal region.

Antibodies, Monoclonal↗
PubMed1988

The tissue distribution of the 3 alpha-fucosyl-N-acetyl lactosamine determinant recognized by the CD15 monoclonal antibodies CMRF-7 and 27.

Two monoclonal antibodies, CMRF-7 and 27, which react with cells of the granulocytic series, were obtained from hybridomas cloned from separate fusions. Biochemical studies indicate that both antibodies are of the CD15 group and react with the antigenic determinant 3 alpha-fucosyl-N-acetyl lactosamine (hapten X) expressed on some glycolipids and several different granulocyte glycoproteins with a wide range of molecular weights. The antigen was found on some promyelocytes and more differentiated granulocytes, including neutrophils and some eosinophils, but not basophils. Monocytes, lymphocytes, and erythrocytes were negative for CMRF-7 but neuraminidase treatment revealed "cryptic" sites on monocytes and some lymphoid cells. The antibody CMRF-7 reacted with the majority of acute myeloid leukemia blasts in the FAB categories M2-M5 but less frequently with M1 blasts and was positive with only 5/43 acute lymphoid leukemias. Immunoperoxidase staining of other normal human tissues indicates that this determinant is found on a range of epithelial cells in skin, the gastrointestinal tract and the genitourinary system. In addition some parts of the central nervous tissue and some endocrine organs stained with these antibodies.

Antibodies, Monoclonal↗
PubMed1988

HLA-DR-positive leucocyte subpopulations in human skin include dendritic cells, macrophages, and CD7-negative T cells.

The immunophenotypes of the HLA-DR-positive leucocyte populations in normal human skin were studied using an extensive panel of monoclonal antibodies, which included antibodies from the Third International Leucocyte Differentiation Antigen Workshop (3rd LDAW). Langerhans' cells (LC) in the epidermis stained with antibodies from CD15c, Groups 10, 12a, 12b and 15, of the myeloid panel and from CD39 of the B-cell panel. However, LC did not react with CD14 antibodies or 63D3, which are frequently used to stain tissue macrophages. In addition to epidermal LC (26 cells/linear mm) a significant population of CD1a-positive cells was identified in the papillary dermis (7 cells/linear mm of overlying epidermis). The dermal HLA-DR-positive leucocytes consisted of three cell populations. The most numerous cell type stained with antibodies to monocytes/macrophages. There were fewer, though substantial, numbers of T lymphocytes (mainly CD7-negative) and the least numerous was the population of CD1a-positive cells. The CD1a-positive cells and the population of dermal cells that stain with monocyte/macrophage markers are both potential antigen-presenting cells for the skin-associated immune system.

Adult↗
PubMed1987

Functional analysis of a clonal expansion of Leu 11 positive NK active lymphoid cells.

A female patient with an unusual lymphoproliferative disease associated with marked neutropenia has been observed for 36 months. The expanded cell population consists of large lymphocytes, many of which contain large azurophilic granules with acid phosphatase activity. These cells were T3, T8, T11 and Leu 11 positive but lacked the M1, T10, IL-2 receptor and HLA.DR antigens. The majority of these cells (60-70%) were also Leu 7 (HNK-1) positive. Strong natural killer (NK) activity was found in both the Leu 7 positive and negative cell populations. This cytotoxic activity was inhibited by monoclonal antibodies known to inhibit NK activity but was unaffected by antibodies which block T cell and T/NK cell cytotoxicity. Further functional analysis indicated that these cells suppressed normal T cell responses to mitogens, MLC responses and PWM induced B cell immunoglobulin synthesis. No effect on bone marrow progenitor cell growth was demonstrated. Antibody dependent cellular cytotoxic (ADCC) activity was barely detectable despite the presence of the Leu 11 antigen. Southern blot DNA analysis demonstrated clonal rearrangement of the T cell receptor beta gene thereby confirming that this variant of T gamma lymphoproliferative disease was a neoplastic condition.

Adult↗
PubMed1987

Monoclonal antibody purified beta 2-microglobulin: heterogeneity revealed by radioimmunoassay.

A monoclonal antibody, CMRF1, to human beta 2-microglobulin (beta 2m) was used to purify antigen to develop an in-house beta 2m radioimmunoassay. This immunoadsorption purified material was used to prepare a rabbit anti-beta 2m serum and was radiolabelled for the radioimmunoassay. The assay compared favourably with a widely used commercial radioimmunoassay but the immunological potency of the in-house standard was lower than that of the commercial reagent. This potency difference was not accounted for by antigenic denaturation. Subsequent two-dimensional gel electrophoresis revealed a second 12,000 dalton protein with a higher isoelectric point than beta 2m in the immunoadsorption purified material, which was also present, although in lesser amounts, in the commercial product. The different relative content of the additional 12,000 dalton protein appeared to explain the immunological potency difference between the in-house and the commercial standard. These results strengthen suggestions that there may be some heterogeneity or polymorphism in human beta 2m.

Antibodies, Monoclonal↗
PubMed1987

Inhibition of natural killer-cell mediated cytolysis with monoclonal antibodies to restricted and non-restricted epitopes of the leucocyte common antigen.

Three monoclonal antibodies recognizing different epitopes of the leucocyte common molecule, CMRF-11 (against the restricted or B-220 leucocyte common molecule), CMRF-12 and CMRF-26 [each against a different epitope on the non-restricted or T200 leucocyte common (CD45) molecule], were tested for their effects on lymphocyte cytotoxicity. The individual monoclonal antibodies inhibited human natural killer cell-mediated cytolysis (NK-CMC) weakly, but a mixture of CMRF-11 + 12 + 26 antibodies inhibited cytolysis more consistently and to a greater extent. This mixture did not inhibit cytotoxic T lymphocytes derived from secondary mixed lymphocyte cultures. The CMRF-11 + 12 + 26 mix was shown to inhibit a post-conjugate formation stage of lysis at the effector cell level. Inhibition of NK-CMC of a wide range of target cells, including the T-cell lines Jurkat, HSB2 and Molt 4, was demonstrated.

Antibodies, Monoclonal↗
PubMed1986

B cell lymphoma presenting as carcinoma of the lung.

A patient presented with superior vena caval obstruction caused by a tumour which resembled carcinoma of the lung both clinically and histologically. However, immunologic and cytogenetic analyses carried out on the mediastinal biopsy and on pleural fluid revealed that the tumour was of B cell origin, Burkitt-like in sub-type, and had the t(8;14) translocation. The nature of many poorly differentiated tumours may be more clearly identified with the help of immunological and cytogenetic analyses.

Antigens, Neoplasm↗
PubMed1986

The inheritance of abnormal sialoglycoproteins found in a Gerbich negative individual.

The Gerbich blood group antigens are probably expressed on one or more of the minor erythrocyte (beta, beta 1, or gamma) sialoglycoproteins which are lacking in some rare individuals having the Gerbich negative phenotype. A monoclonal antibody, CMRF-10, which recognises a trypsin-sensitive site on both the beta and beta 1 sialoglycoproteins, was tested for binding to erythrocytes from a Gerbich negative individual, OM. Erythrocytes from OM bound CMRF-10 in similar amounts to normal erythrocytes even though membranes from OM were shown by sodium dodecyl sulphate-polyacrylamide gel electrophoresis to lack both the beta and gamma sialoglycoproteins found in normal red blood cells. Instead, abnormal sialoglycoproteins which migrated as two bands with apparent molecular weights within the range 29,500-32,500 daltons were identified and purified using CMRF-10. Subsequent electrophoretic analysis of OM's two children failed to reveal any abnormal sialoglycoproteins. This suggests that in this instance the Gerbich negative phenotype may result from other mechanisms, possibly defective glycosylation, rather than a crossover involving the gene coding for the primary protein structure of the sialoglycoproteins.

Aged↗