Human macrophage maturation and heterogeneity: analysis with a newly generated set of monoclonal antibodies to differentiation antigens

We have analyzed the expression of late differentiation antigens during terminal in vitro maturation of human macrophages (M phi) from blood monocytes (MO) in comparison to their distribution among mature M phi residing in various tissue sites. By immunizing mice with M phi derived from blood MO by culture on hydrophobic Teflon foils, monoclonal antibodies (mAbs) were developed (MAX.1, MAX.2, MAX.3, MAX.11) that reacted with lineage-restricted differentiation antigens. These antigens were expressed exclusively on M phi or were markedly increased after in vitro differentiation. The only overlap to another hemopoietic cell lineage was observed with MAX.3, which is shared by platelets and megakaryocytes. In the course of M phi maturation in vitro, the MAX.1 and MAX.3 antigens are detected within the cytoplasm two days before they appear on the cell surface. In contrast, the MAX.11 antigen is expressed simultaneously in the cytoplasm and at the cell surface, is found in varying degrees on a minor portion of blood MO and U937 cells, and is expressed rapidly at high density during early M phi differentiation in vitro. Among conventional mAbs that do not react with MO we found those against the transferrin (TF)-receptor, the BA-2, and the PCA1 antigen to label M phi. M phi matured in vivo and isolated from body fluids were positive with some but not all MAX mAbs. Distinctive patterns were observed with pulmonary M phi, exudate M phi from pleural and peritoneal effusions, synovial fluids, and early lactation milk. M phi from the alveolar space, for example, constantly expressed the MAX.2 antigen but not the MAX.3 antigen. Pleural effusion M phi, however, did not react with the MAX.1 mAb, but in most cases, it did react with the MAX.3 mAb. The detection of novel differentiation antigens, all expressed on monocyte-derived M phi but differently expressed on site-specific M phi in situ, underlines the remarkable heterogeneity among human M phi. The expression of these antigens is flexible because those MAX antigens that were not expressed in situ could be induced if cells from distinct tissue sites were cultured in vitro for several days. MAX mAbs may be of potential value to study both the sequential stages of maturation within the M phi lineage as well as differential developments induced by various culture conditions in parallel to environmental factors in vivo.     

Ca2+ and phospholipid-dependent protein kinase (protein kinase C) activity is not necessarily required for secretion by human neutrophils

Ca2+-dependent and phospholipid-dependent protein kinase (PKC) is a receptor for and is activated by phorbol esters. This enzyme is reportedly involved in the mechanism of superoxide anion (O2-) production and the release of intracellular granule contents from human neutrophils. As previously reported by others, we found that greater than 75% of the total cellular PKC activity existed in a soluble form in untreated neutrophils and that this activity was enhanced in a dose- dependent manner by phorbol 12-myristate 13-acetate (PMA) and by phorbol 12,13-dibutyrate (PDBu). Furthermore, mezerein, an analogue of PMA that is thought to be a competitive inhibitor, did not activate PKC, and on the contrary, inhibited PMA-stimulated activity in a dose- dependent manner. Pretreatment of intact neutrophils with PMA or PDBu caused the "translocation" of PKC activity to the insoluble cell fraction; PKC translocation was not detected after mezerein stimulation at any of the tested concentrations. Neither did mezerein cause an increase in intracellular Ca2+, as monitored by Quin 2 fluorescence. Both phorbol esters and mezerein stimulated intact neutrophils to generate O2- and release lysosomal enzymes into the extracellular medium. Finally sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated key differences in the patterns of endogenous phosphoproteins of neutrophils stimulated with phorbol as compared with mezerein. We therefore suggest that PKC activation may not be the only pathway required to elicit neutrophil responses.     

内皮下脂蛋白滞留——动脉粥样硬化的始动过程

以动脉粥样硬化为基础的心血管疾病是人类健康面临的严重挑战.人们对动脉粥样硬化发生、发展进行漫长和不懈的探索.至今,其机制与过程仍不十分清楚.     

Silent myocardial ischemia: Current perspectives and future directions

Silent myocardial ischemia (SMI) is increasingly being recognized as part of the spectrum of ischemic heart disease. The spectrum of SMI ranges from asymptomatic coronary artery disease to critical illness necessitating intensive care. Although many diagnostic tools have been used to identify low- and high-risk subgroups, their use is limited by modest sensitivities and specificities. The present review identifies current concepts in the management of SMI in various clinical settings, as well as emerging technologies that may simplify the diagnosis and treatment of this condition.     

Imatinib Inhibits the Renewal and Tumorigenicity of CT-26 Colon Cancer Cells after Cytoreductive Treatment with Doxorubicin

Archivum Immunologiae et Therapiae Experimentalis - Conventional anti-cancer drugs preferentially eliminate differentiated cancer cells but those cells that are spared (i.e. cancer stem cells:...     

Candida-specific systemic cell-mediated immune reactivities in human immunodeficiency virus-positive persons with mucosal candidiasis

Oropharyngeal candidiasis (OPC), as opposed to vulvovaginal candidiasis (VVC), is a common opportunistic infection in human immunodeficiency virus (HIV)-positive persons that correlates with reduced CD4 T cell counts. Although cell-mediated immunity (CMI) by CD4 Th1-type cells is considered to be the predominant host defense against mucosal candidiasis, the immune factors associated with susceptibility to OPC in HIV-positive persons are not well understood. This study investigated Candida-specific systemic CMI in HIV-positive persons with OPC and/or VVC. Reductions in delayed skin test reactivity to Candida antigen were observed in HIV-positive persons with CD4 cell counts <200 cells/microL, irrespective of the presence of mucosal infection. Likewise, despite the correlate of OPC with reduced CD4 cell counts in HIV-positive persons, differences in Candida-specific peripheral blood mononuclear cell proliferation and Th1/Th2 cytokine production between HIV-positive and HIV-negative persons were not consistent in a manner to suggest that deficiencies in Candida-specific systemic CMI account solely for the susceptibility to OPC.     

Chronic lower limb wounds evoke systemic response of the lymphatic (immune) system

Wound healing should not be considered as a process limited only to the damaged tissues. It is always accompanied by an intensive local immune response and in advanced stages, the systemic lymphatic (immune) structure. In this review we present evidence from our own studies as well as pertinent literature on the role of skin and subcutaneous tissue lymphatics at the wound site and of transport of antigens along with collecting afferent lymphatics to the lymph nodes. We also speculate the role of lymph nodes in raising cohorts of bacterial and own tissue antigen-specific lymphocytes and their participation in healing and not infrequently evoking uncontrolled chronic immune reaction causing a delay of healing. It is also speculated as to why there is a rapid response of lymph node cells to microbial antigens and tolerance to damaged-tissue-derived antigens occursKEY WORDS: Healing, immunity, wound     

Neutrophil elastase produces 52-kD and 30-kD glucocorticoid receptor fragments in the cytosol of human leukemia cells

Characterization of glucocorticoid receptors in leukemia cells is important to understand mechanisms of glucocorticoid resistance but has been impeded by receptor fragmentation in cytosol extracts. We recently found that formation of 52- and 30-kilodalton (kD) glucocorticoid receptor fragments in cytosol of leukemia cells is due to proteolysis and is blocked by diisopropylfluorophosphate (DFP). In the present study, we identify a 28-kD serine protease in cytosol of leukemia cells that binds [3H]DFP and correlates with the formation of 52- and 30-kD receptor fragments. This protease is immunoprecipitated by antiserum to neutrophil elastase. Limited digestion of [3H]dexamethasone-21-mesylate- labeled receptors by purified neutrophil elastase produces 52- and 30- kD receptor fragments. Receptor fragmentation in the cytosol of leukemia cells in inhibited by methoxysuccinyl-alanyl-alanyl-prolyl- valyl-chloromethylketone, a highly specific inhibitor of neutrophil elastase. The addition of as few as 5% neutrophils to a lymphoid cell suspension provides sufficient elastase to produce receptor fragmentation. Our findings indicate that neutrophil elastase is responsible for receptor fragmentation in the cytosol of leukemia cells. The neutrophil elastase may be endogenous to the leukemia cells or may come from neutrophils that contaminate leukemia cell suspensions.