EL-4 and macrophages: generation of chemotactic monokines

Various effects of EL-4 lymphoma supernatant fluids on macrophages were studied. Macrophages migrate under agarose to medium conditioned by the EL-4 cell line for up to 40 h. EL-4 conditioned medium after 67 h contained dialyzable migration inhibitors. In addition, upon direct treatment with the EL-4 supernatant, macrophages took on a more elongated or polarized morphology as compared to control medium or another tumour cell line conditioned medium. A 2 h treatment of macrophages with the EL-4 culture supernatant was sufficient to trigger the production and/or release of chemotactic monokines. These monokines were chemotactic for both PMNs and macrophages. In addition, a prior state of activation of the macrophage does not appear to be necessary for the production and/or release of the chemotactic monokines since resident as well as stimulated peritoneal macrophages are equally effective.     

Killing of Mycobacterium tuberculosis within human monocytes: activation by cytokines and calcitriol.

Human monocytes were isolated and their ability to harbour growth of virulent tubercle bacilli was assessed, in the presence or absence of various immunomodulators. Calcitriol (1,25(OH2), vitamin D3) alone, at doses of 10(-7)-10(-9) M endowed human monocytes with a significant ability to restrict intracellular growth of the tubercle bacilli. Crude immune lymphokines as well as recombinant interferon-gamma (IFN-gamma) endowed monocytes with no tuberculostatic activity. Similarly, other recombinant cytokines tested, notably colony-stimulating factor-1 (CSF-1), interleukin-1 (IL-1), interleukin-3 (IL-3) and interleukin-6 (IL-6) all failed to stimulate anti-tuberculous properties, and even increased growth of the tubercle bacilli in monocytes, in the case of CSF-1. Conversely, incubation of crude lymphokines in combination with calcitriol led to total stasis of the growth of M. tuberculosis. Experiments with recombinant cytokines and immunologically active vitamins showed that a combination of IFN-gamma tumour necrosis factor-alpha and calcitriol induced a significant amount of intramonocyte killing of M. tuberculosis. Addition of this cocktail of factors to already infected monocytes led to substantial killing of tubercle bacilli. These sets of experiments establish clearly that combinations of recombinant cytokines and vitamins may induce substantial intramonocyte killing of M. tuberculosis. The mechanism involved in this killing activity was not clarified.     

A non-classical monocyte-derived macrophage subset provides a splenic replication niche for intracellular Salmonella

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Role of the lung macrophages in regulation of the quantity of alveolar surfactant

Fixation of the rat lung by perfusion through the pulmonary artery prevents the flushing of the macrophages into the lumen of the alveoli and maintains their natural distribution in the hypophase of the alveolar extracellular lining, beneath the film of surfactant. Surfactant synthesis is intensified in the large, alveolocytes of the remaining lung 5–7 days after left-sided pneumonectomy, the quantily of tubular myelin in the hypophase of the hypertrophied alveoli is increased, and the surface tension of the lung washings falls. The number of alveolar macrophages is more than doubled in this period. The alveolar macrophages utilize the excess of surfactant (tubular myelin) in the hypertrophied lungs and so participate in the regulation of the surface tension of the alveoli.Laboratory of Geographic Pathology of the Baikal-Amur Railroad Zone, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 12, pp. 646–650, December, 1977.     

Mast cells at the host-pathogen interface: host-protection versus immune evasion in leishmaniasis

Infection of a susceptible host with Leishmania, a protozoan parasite, causes the disease leishmaniasis, which is characterized by neutrophil, eosinophil, macrophage, lymphocyte and mast cell infiltration into the infected tissue followed by parasite growth. Although the roles played by other cells in leishmaniasis are known, the role of mast cells remains to be ascertained. Here, we demonstrate that Leishmania regulates mast cell infiltration to the site of infection, mast cell production and mast cell function resulting in differential growth of the parasite in resistant (C57BL/6 or CBA/T6T6) and susceptible (BALB/c) macrophages. An interleukin-3-dependent augmentation in mast cell committed progenitors is observed in BALB/c but not in C57BL/6 mice during Leishmania infection. The mast cell supernatants inhibit IFN-gamma-dependent restriction of Leishmania growth in macrophages in BALB/c mice whereas the reverse phenomenon occurs in C57BL/6 mice. Our data reveals a different facet of host-pathogen interaction.     

Expression of TNFalpha by muscle fibers in biopsies from children with untreated juvenile dermatomyositis: association with the TNFalpha-308A allele

Juvenile dermatomyositis (JDM) is the most common pediatric inflammatory myopathy. In patients with JDM, the A --> G polymorphism in the tumor necrosis factor alpha (TNFalpha)-308 promoter region (TNFalpha-308A) is associated with prolonged disease course and increased production of TNFalpha by peripheral blood mononuclear cells (Arthritis Rheum. 43, 2368-2377, 2000). Magnetic resonance imaging directed biopsies from 21 white children with untreated JDM were evaluated for TNFalpha expression. Using monoclonal antibody to TNFalpha, fresh frozen sections were processed by the standard immunohistochemical technique. We investigated the association among the expression of TNFalpha by muscle fibers, disease activity, duration of untreated disease, and the TNFalpha-308 polymorphism. Untreated children with JDM who had the TNFalpha-308A allele had an increased number of TNFalpha stained muscle fibers than children with the TNFalpha-308G allele (P = 0.001). There was no association with disease activity or duration of untreated disease. We speculate that muscle fiber production of TNFalpha provides a microenvironment in which TNFalpha acts synergistically with other mediators to prolong muscle fiber damage.     

Effects of cobalt and chromium ions on glycolytic flux and the stabilization of hypoxia‐inducible factor‐1α in macrophages in vitro

Implant wear and corrosion have been associated with adverse tissue reactions that can lead to implant failure. Wear and corrosion products are therefore of great clinical concern. For example, Co²⁺ and Cr³⁺ originating from CoCrMo‐based implants have been shown to induce a proinflammatory response in macrophages in vitro. Previous studies have also shown that the polarization of macrophages by some proinflammatory stimuli is associated with a hypoxia‐inducible factor‐1α (HIF‐1α)‐dependent metabolic shift from oxidative phosphorylation (OXPHOS) towards glycolysis. However, the potential of Co²⁺ and Cr³⁺ to induce this metabolic shift, which plays a determining role in the proinflammatory response of macrophages, remains largely unexplored. We recently demonstrated that Co²⁺, but not Cr³⁺, increased oxidative stress and decreased OXPHOS in RAW 264.7 murine macrophages. In the present study, we analyzed the effects of Co²⁺ and Cr³⁺ on glycolytic flux and HIF‐1α stabilization in the same experimental model. Cells were exposed to 6 to 24 ppm Co²⁺ or 50 to 250 ppm Cr³⁺. Glycolytic flux was determined by analyzing extracellular flux and lactate production, while HIF‐1α stabilization was analyzed by immunoblotting. Results showed that Co²⁺, and to a lesser extent Cr³⁺, increased glycolytic flux; however, only Co²⁺ acted through HIF‐1α stabilization. Overall, these results, together with our previous results showing that Co²⁺ increases oxidative stress and decreases OXPHOS, suggest that Co²⁺ (but not Cr³⁺) can induce a HIF‐1α‐dependent metabolic shift from OXPHOS towards glycolysis in macrophages. This metabolic shift may play an early and pivotal role in the inflammatory response induced by Co²⁺ in the periprosthetic environment.     

Inflammation,immunity and allergy

Injury or foreign invasion will instigate a cascade of events directed at eliminating the intruder and augmenting the healing process. This involves the unification of two separate processes (inflammatory and immune processes) to provide an effective host defence. Chemical mediators converge on the site of tissue damage and exert local and distant effects. The immune response is divided into innate and acquired immunity. The immediate, non-specific innate response, combined with the specifically targeted acquired response, provide our major defence mechanisms. Lymphocytes and immunoglobulins are the hallmark of acquired immunity. Regulation of these interlinked systems provide cohesion and a group of soluble proteins called cytokines have a major role. Protective immune mechanisms can sometimes cause detrimental effects to the host. We discuss and classify allergic reactions, in particular, the most severe and potentially life threatening form – anaphylaxis.     

LncRNA PCED1B-AS1调控NLRP3促进巨噬细胞清除结核分枝杆菌的机制研究

目的　研究长链非编码RNA PCED1B-AS1调控核苷酸结合寡聚化结构域样受体3（NLR family pyrindomain containing 3, NLRP3）对巨噬细胞清除结核分枝杆菌和分泌炎症因子的影响。方法　在巨噬细胞RAW264.7中转染pcDNA-PCED1B-AS1,并用结核分枝杆菌感染,qRT-PCR方法检测PCED1B-AS1和TNF-α、IL-6 mRNA水平,用菌落形成实验检测巨噬细胞对结核分枝杆菌的清除作用,Western blot方法检测细胞中NLRP3蛋白表达水平。将NLRP3 小干扰RNA（small interfering RNA, siRNA）和pcDNA-PCED1B-AS1共转染到巨噬细胞中,用结核分枝杆菌感染,同样检测细胞中TNF-α、IL-6 mRNA水平和菌落量。结果　结核分枝杆菌感染后的巨噬细胞中PCED1B-AS1水平降低,TNF-α、IL-6 mRNA水平升高。转染pcDNA-PCED1B-AS1后的巨噬细胞经过结核分枝杆菌感染以后,细胞中PCED1B-AS1、TNF-α、IL-6 mRNA水平升高,形成的菌落量减少,细胞中NLRP3蛋白表达水平升高。NLRP3 siRNA可以逆转过表达PCED1B-AS1对结核分枝杆菌感染的巨噬细胞中TNF-α、IL-6 mRNA表达和菌落量形成的影响。结论　上调PCED1B-AS1促进巨噬细胞清除结核分枝杆菌,诱导细胞表达TNF-α、IL-6 mRNA的机制与上调NLRP3表达有关。