Biomedical subjects

Peter J Macardle

Publications and source records attributed to Peter J Macardle.

7 recordsLinked to original sources

PubMed2006

CD molecules 2006--human cell differentiation molecules.

The Human Leucocyte Differentiation Antigens Workshops (HLDA) have since 1984 provided a forum for the characterization and study of leucocyte surface molecules and antibodies against them. HLDA devised the CD nomenclature, which is sanctioned by IUIS. The HLDA Council reviewed and modified the objectives of HLDA in 2004, and changed the name of the organization to Human Cell Differentiation Molecules (HCDM) to reflect the broader objectives. Workshop studies under the HCDM banner proceeded during 2005 and early 2006, culminating in a meeting in May 2006. At that meeting the Council, acting as Nomenclature Committee, approved a number of new CD designations and changes to some pre-existing CD designations, which are summarized in this report.

Antigens, CD↗

PubMed2006

A flow cytometric comparison of Indo-1 to fluo-3 and Fura Red excited with low power lasers for detecting Ca(2+) flux.

Indo-1 and high-power water-cooled lasers have been the standard for flow cytometric based Ca(2+) flux measurements. With advances in technology and the availability of low-power air-cooled lasers, there is interest in alternative protocols. Here, we have compared Indo-1 with the combination of fluo-3 and Fura Red calcium indicator dyes using low-power air-cooled lasers as the excitation source. The reagents were examined in parallel to detect Ca(2+) flux in peripheral blood T lymphocytes and in a T lymphoblastoid cell line. Ca(2+) flux was detected with a FACSVantage SE equipped with an Omnichrome Series 74 Helium-Cadmium, or a Spectra Physics 177-G1202 Argon ion air-cooled laser. Following determination of optimal loading conditions, Ca(2+) flux was examined in response to membrane receptor stimulation or intracellular Ca(2+) mobilization. Dose dependent Ca(2+) flux to anti-CD3 and thapsigargin was detected with either Indo-1 or with fluo-3 and Fura Red. The profile of the Ca(2+) flux detected by Indo-1 or with fluo-3 and Fura Red appeared similar, with the combination of fluo-3 and Fura Red more sensitive under the particular test conditions. The results clearly demonstrated that Indo-1 could be usefully excited with a low-power air-cooled laser. The alternative use of fluo-3 and Fura Red does not require the availability of a UV capable laser and produced equivalent data.

Aniline Compounds↗

PubMed2006

Eosinophilic mucus chronic rhinosinusitis: clinical subgroups or a homogeneous pathogenic entity?

BACKGROUND: Eosinophilic mucus chronic rhinosinusitis (EMCRS) can be subclassified using the criteria of detection of fungi in eosinophilic mucus and systemic fungal allergy. Allergic fungal sinusitis (AFS), a subgroup of EMCRS characterized by the presence of fungal allergy, is proposed to be an immunoglobulin (Ig)E-driven disease, distinct from other EMCRS subgroups. However, our recent studies cast doubt on the central pathogenic role of allergy in AFS. The purpose of this study was to examine the clinical features of EMCRS patients from the different subcategories to determine the relevance of this classification system. METHOD: The demographic, clinical, and immunologic characteristics of the EMCRS subgroups were examined prospectively and compared with three control groups: healthy volunteers, allergic rhinitis with fungal allergy, and chronic rhinosinusitis without eosinophilic mucus. RESULTS: EMCRS patients with allergy were younger than those without. There was no significant difference in clinicopathologic parameters between EMCRS subgroups. As a single group, EMCRS had a more severe sinus disease compared with chronic rhinosinusitis patients. CONCLUSIONS: AFS was not clinically distinct from other subgroups of EMCRS. However, eosinophilic mucus may mark a more severe and distinct form of sinus disease.

Adult↗

PubMed2005

Fungal-specific humoral response in eosinophilic mucus chronic rhinosinusitis.

OBJECTIVES/HYPOTHESIS: An immunoglobulin (Ig)E-mediated allergic pathogenesis is presumed in allergic fungal sinusitis (AFS), yet extensive polyps and eosinophilic mucus (EM) in the paranasal sinuses may also occur in the absence of allergy. Although a noninvasive fungal pathogenesis is presumed in all chronic rhinosinusitis with EM (EMCRS), fungal-specific nonallergic immune responses have not been thoroughly investigated. We tested the hypothesis that there is a fungal-specific humoral response in EMCRS and that it is not confined to IgE. STUDY DESIGN: EMCRS patients were prospectively stratified into subgroups based on the presence or absence of fungi within EM and of fungal-specific systemic IgE. There were 12 AFS, 5 AFS-like, 8 nonallergic fungal eosinophilic sinusitis (NAFES), and 5 nonallergic, nonfungal eosinophilic sinusitis (NANFES) patients. METHODS: Alternaria alternata and Aspergillus fumigatus-specific serum IgE, IgG, IgM, and IgA was measured by enzyme-linked immunosorbent assay and compared with strictly defined healthy and disease-control groups. RESULTS: Fungal-specific IgG (Alternaria alternata P = .0002; Aspergillus fumigatus P = .004), and IgA levels (Alternaria alternata P = .0016; Aspergillus fumigatus P = .002) were higher in EMCRS compared with healthy volunteers but not with disease controls. Fungal-specific IgG3 levels were significantly elevated in all the EMCRS subgroups compared with controls for either fungal antigen (P < .0001). Importantly, fungal-specific IgE levels were not significantly different between fungal-allergic EMCRS and disease controls. CONCLUSIONS: Fungal-specific immunity characterized by serum IgG3 and not IgE, distinguished the EMCRS subgroups from control groups regardless of the presence of fungus within EM or of systemic fungal allergy. Fungal-specific IgE responses in fungal-allergic EMCRS were no different to those in fungal-allergic controls, thus challenging the presumption of a unique pathogenic role of fungal allergy in "allergic fungal sinusitis."

Adolescent↗

PubMed2004

Detection of low-abundance membrane markers by immunofluorescence--a comparison of alternative high-sensitivity methods and reagents.

The analysis of membrane molecules using antibodies detected by immunofluorescence staining and flow cytometry is used widely in research and diagnostic immunology. Conventional staining techniques readily detect molecules present at concentrations of around 2000 molecules per cell, but some molecules are expressed and function at much lower abundance. We described previously a method for the detection of molecules present at 100 molecules per cell or less based on the use of phycoerythrin as the fluorophore, a three-layer amplification process, and careful selection of available reagents. In recent years, a number of new reagents, fluorophores and kits, have become available, some of them intended for high-sensitivity applications. In this paper, a number of these reagents have been compared with the published method. While some of the reagents gave variable results or high nonspecific staining in our hands, several reagents were comparable with the published method. Furthermore, the new fluorophores allow improved simultaneous detection of two low-abundance markers.

Antibodies↗

PubMed2002

FcgammaRIIb expression on human germinal center B lymphocytes.

IgG antibody can specifically suppress the antibody response to antigen. This has been explained by the hypothesis that signaling through the B cell antigen receptor is negatively modulated by the co-ligation of immunoglobulin with the receptor for IgG, FcgammaRIIb. We hypothesized that inhibitory signaling through FcgammaRIIb would be counter-productive in germinal center cells undergoing selection by affinity maturation, since these cells are thought to receive a survival/proliferative signal by interacting with antigen displayed on follicular dendritic cells. We have identified and characterized a population of B lymphocytes with low/negative FcgammaRIIb expression that are present in human tonsil. Phenotypically these cells correspond to germinal center B cells and comprise both centroblast and centrocyte populations. In examining expression at the molecular level we determined that these B cells do not express detectable mRNA for FcgammaRIIb. We examined several culture conditions to induce expression of FcgammaRIIb on germinal center cells but could not determine conditions that altered expression. We then examined the functional consequence of cross-linking membrane immunoglobulin and the receptor for IgG on human B lymphocytes. Our results cast some doubt on the value of anti-IgG as a model for antigen-antibody complexes in studying human B cell regulation.

B-Lymphocyte Subsets↗

PubMed2002

Anti-La/SSB antibodies transported across the placenta bind apoptotic cells in fetal organs targeted in neonatal lupus.

OBJECTIVE: To determine whether La and/or Ro epitopes on apoptotic cells in fetal organs that are targeted in neonatal lupus syndrome (NLS) are accessible for binding by autoantibodies in vivo, we traced the fate of transplacental autoantibodies in a murine passive transfer model. METHODS: Pregnant mice at day 15 of gestation (E15) were injected intraperitoneally with human anti-Ro/La-positive sera or control sera, and transplacental transfer of human autoantibodies was tested by enzyme-linked immunosorbent assay with recombinant antigens. Multiple cryostat sections at the level of the heart of E17 fetuses were visualized simultaneously for human IgG binding and apoptosis (TUNEL) under confocal microscopy. Serial paraffin sections of E17 and E19 fetuses were examined for histologic evidence of inflammation. RESULTS: Human IgG anti-52-kd Ro, anti-60-kd Ro, and anti-La autoantibodies were transported efficiently into the fetal circulation. Human IgG-apoptotic cell complexes were detected in the heart (atrial trabeculae and atrioventricular node), skin, liver, and newly forming bone of fetuses from mothers injected with anti-Ro/La sera but not control sera. The IgG binding was fetal-specific and organ-specific; transplacental autoantibodies did not bind to apoptotic cells in the fetal thymus, lung, brain, or gut. The complexes were not associated with an inflammatory reaction. Injection of mothers with affinity-purified anti-La autoantibodies (but not anti-Ro/La Ig depleted of anti-La) revealed an identical location of IgG binding to apoptotic cells in the fetuses. CONCLUSION: This is the first study to demonstrate that transplacental anti-La autoantibodies bind specifically to apoptotic cells in selected fetal organs in vivo, similar to the organ involvement in NLS. We hypothesize that additional factors are required to promote proinflammatory clearance of IgG-apoptotic cell complexes and subsequent tissue damage.

Animals↗