D-Penicillamine and Macrophages: Modulation of Lymphocyte Transformation by Concanavalin A

Pretreatment with D-Penicillamine of rat peritoneal macrophages markedly influences their ability to modulate Concanavalin A stimulated [3H]thymidine incorporation in non-adherent rat lymph node cells. Untreated macrophages added in high numbers to the lymphocytes (ratio lymphocytes/macrophage 7.5 : 1) depress their [3H]thymidine incorporation. Pretreatment with D-Penicillamine further reduces this response. Lower proportions of untreated macrophages (ratio 15 : 1) exert a stimulatory effect on the lymphocytes. This response is reversed by pretreatment of macrophages with D-Penicillamine. Addition of untreated macrophages in very low proportions (40 : 1 and 75 : 1) is without effect on the [3H]thymidine incorporation by the lymphocytes. This response is markedly stimulated by pretreatment of the macrophages with D-Penicillamine. The culture of macrophages in the presence of D-Penicillamine increases their incorporation of [3H]D-glucosamine, but it is without effect on their incorporation of [3H]L-leucine. It is suggested that D-Penicillamine enhances the functional activity of the macrophage in the regulation of the lymphocyte response to mitogens.     

Lymphocyte Activation in Rheumatoid Arthritis Synovial Fluid in Vivo

Monoclonal antibodies were used in avidin-biotin-peroxidase complex staining for activation marker analysis of rheumatoid synovial fluid cells. Although Ia expression indicates T cell activation, cells displaying receptors for interleukin 2 (Tac)-and transferrin receptor (T9)- positive proliferating cells were relatively few. Similarly, activated terminal effector cells of suppressor/cytotoxic nature were scarce in rheumatoid synovial fluid, as suggested by a low expression of Tac and 4F2 markers. The in vivo situation in the rheumatoid arthritic (RA) joint does not seem to be due to the inability of synovial fluid lymphocytes to become activated, because mitogen stimulation in vitro, in spite of a low proliferative response, induced expression of all the activation markers studied. The relevance of the present observations to the down-regulation of the active, inflammatory-immune response in situ is speculative, but the data show that in spite of T-cell activation and Ia expression, activated terminal effector cells of suppressor/cytotoxic nature are few in the RA joint in vivo.     

Role of Complement Receptors in Uptake of Mycobacterium avium by Macrophages In Vivo: Evidence from Studies Using CD18-Deficient Mice

Mycobacterium avium is an intracellular pathogen that has been shown to invade macrophages by using complement receptors in vitro, but mycobacteria released from one cell can enter a second macrophage by using receptors different from complement receptors. Infection of CD18 (beta(2) integrin) knockout mice and the C57 BL/6 control mice led to comparable levels of tissue infection at 1 day, 2 days, 1 week, and 3 weeks following administration of bacteria. A histopathological study revealed similar granulomatous lesions in the two mouse strains, with comparable numbers of organisms. In addition, transmission electron microscopy of spleen tissues from both strains of mice showed bacteria inside macrophages. Our in vivo findings support the hypothesis that M. avium in the host is likely to use receptors other than CR3 and CR4 receptors to enter macrophages with increased efficiency.     

Inhibition of Spontaneous and Mitogen-Induced Lymphocyte Proliferation by Murine Bone Marrow-Derived Macrophages: Role of Prostaglandins, Nitric Oxides and Cell-to-Cell Contact

Spontaneous and mitogen-stimulatcd proliferation of spleen lymphocytes was inhibited by coculturing the cells with murine bone marrow derived macrophages (BM-Mφ). The inhibitory effect was found to be dependent on the maturation stage of BM-Mφ reflected by the appearance of the phenotype BM 8 and on the number of BM-Mφ added to the lymphocytes. The spontaneous proliferation was only inhibited by the addition of high numbers of BM-Mφ of late maturation stage. The lipopolysaccharide (Lps) induced response was strongly suppressed by increasing proportions of BM-Mφ of either cultivation stage. The suppressive effect on the concanavalin A (Con A)-induced proliferative activity increased with the maturation of the macrophages. Inhibition of prostanoid release with indomethacin had no effect. Blocking of nitric oxide synthesis partially reversed the inhibitory effect of macrophages mainly on the Con-A response. Addition of culture supernatant of BM-Mφ to the lymphocytes did not mimic the effect of the macrophages themselves. BM-Mφ only slightly inhibited the proliferation when 1ymphocyte-BM-Mφ cell-to-cell contact was prevented. These results show that BM-Mφ differently influence the spontaneous and mitogen-induced lymphoproliferation and that the inhibitory effect of BM-Mφ on the lymphocyte proliferation is only partially mediated by secretory products of macrophages but apparently requires cell-to-cell contact between both cell types.     

The Role of Macrophages in Wallerian Degeneration

The present review focuses on macrophage properties in Wallerian degeneration. The identification of hematogenous phagocytes, the involvement of cell surface receptors and soluble factors, the state of activation during myelin removal and the signals and factors leading to macrophage recruitment into degenerating peripheral nerves after nerve transection are reviewed. The main effector cells in Wallerian degeneration are hematogenous phagocytes. Resident macrophages and Schwann cells play a minor role in myelin removal. The macrophage complement receptor type 3 is the main surface receptor involved in myelin recognition and uptake. The signals leading to macrophage recruitment are heterogenous and not yet defined in detail. Degenerating myelin and axons are suggested to participate. The relevance of these findings for immune-mediated demyelination are discussed since the definition of the role of macrophages might lead to a better understanding of the pathogenesis of demyelination.     

Influence of in Vivo Hydrocortisone on Some Human Blood Lymphocyte Subpopulations

The effect of in vivo hydrocortisone (OHC) on natural killer (NK) activity was studied using the K562 cell line as target in a 3-h ⁵¹Cr-release assay. Peripheral blood lymphocytes obtained from live normal volunteers at 0, 4, 24 and 48 h after Intravenous administration of 300 mg of OHC showed significantly increased NK activity at 4 h, decreased activity at 24 h, with a return toward normal at 48 h. Parallel variation were found in the fraction of lymphocytes bearing receptor for the Fe part of IgG. However, neither the number of these cell nor the NK activity was influenced by the medication when the results were given per millilitre of blood. In vitro pre-incubation of the effector with OHC for 24 h had no effect on viability, expression of surface markers, or NK activity. It is concluded that under the present conditions NK activity is OHC-resistant. The variations observed after in vivo administration seem to be due to a reversible redistribution mainly affecting cells other than the NK effectors.     

A Role for Activated Macrophages in Resistance to Infection with Toxoplasma

Activated macrophages from mice which were chronically infected with Toxoplasma gondii or Besnoitia jellisoni, or which had received Freund complete adjuvant, had an enhanced capacity to to kill intracellular Toxoplasma. Enhanced killing by activated macrophages was demonstrated by decreased incorporation of isotopically labeled uridine by intracellular Toxoplasma and by inhibition of plaque formation. The latter resulted from lack of proliferation of the intracellular Toxoplasma which is normally followed by destruction of the host cell (macrophage) and secondary invasion and destruction of fibroblast monolayers.     

β-Endorphin Enhances Phagocytosis of Latex Particles in Mouse Peritoneal Macrophages

The effects of β-endorphin (βEnd) on phagocytosis in peritoneal macrophages were examined by using flow cytometry (FCM). βEnd enhanced phagocytosis in a dose-dependent manner. Leucine—enkephalin (Leu-Enk), methionine—enkephalin (Met—Enk), α-endorphin (αEnd), γ-endorphin (γEnd), αEnd (18–31) and βEnd (28–31) had no such activity. βEnd (1–27) and βEnd (6–31) enhanced phagocytosis less effectively than βEnd did. Naloxone did not inhibit the enhancement of phagocytosis induced by βEnd. Unstimulated control phagocytosis was partially suppressed in Ca²⁺-free EGTA-containing solution and even in this solution βEnd enhanced phagocytosis. However, the enhancement was suppressed in the solution containing BAPTA-AM. The present study showed that βEnd enhanced extracellular Ca²⁺ ([Ca²⁺]_o)-dependent and -independent phagocytosis and that the enhancement is largely dependent on intracellular Ca²⁺ ([Ca²⁺]_i). These results support the contention that βEnd is one of the mediators that modulates the immune system.     

A Rapid Ex Vivo Clinical Diagnostic Assay for Fas Receptor-Induced T Lymphocyte Apoptosis

Deleterious mutations in genes involved in the Fas apoptosis pathway lead to Autoimmune Lymphoproliferative Syndrome (ALPS). Demonstration of an apoptosis defect is critical for the diagnosis and study of ALPS. The traditional in vitro apoptosis assay, however, requires a week of experimental procedures. Here, we show that defects in Fas-induced apoptosis in PBMCs can be evaluated directly ex vivo using multicolor flow cytometry to analyze the apoptosis of effector memory T cells, a Fas-sensitive subset of PBMCs. This method allowed us to sensitively quantify defective apoptosis in ALPS patients within a few hours. Some ALPS patients (ALPS-sFAS) without germline mutations have somatic mutations in Fas specifically in double-negative αβ T cells (DNTs), an unusual lymphocyte population that is characteristically expanded in ALPS. Since DNTs have been notoriously difficult to culture, defective apoptosis has not been previously demonstrated for ALPS-sFAS patients. Using our novel ex vivo apoptosis assay, we measured Fas-induced apoptosis of DNTs for the first time and found that ALPS-sFAS patients had significant apoptosis defects in these cells compared to healthy controls. Hence, this rapid apoptosis assay can expedite the diagnosis of new ALPS patients, including those with somatic mutations, and facilitate clinical and molecular investigation of these diseases.     

Lymphocyte Transformation in Nickel Allergy: Amplification of T-lymphocyte Responses to Nickel Sulphate by Macrophages in Vitro

The cell-mediated immunity of thirty-four nickel contact dermatitis patients was evaluated by performing lymphocyte stimulations with NiSO4 (1.25 and 6.25 microgram/ml) and tuberculin (PPD), phytohaemagglutinin-P, pokeweed mitogen, and concanavalin A. Twenty-six of the patients were nonatopic and eight atopic. Forty-nine healthy subjects served as controls. Nickel sulphate stimulation was significantly increased (P < 0.005) in the allergic subjects, whereas PPD stimulation was decreased (P = 0.01). The responses to the other mitogens did not differ significantly between the control subjects and the patients. The lymphocyte transformation reaction to nickel sulphate was shown to occur in T cells and to be enhanced by the helper function of macrophages.     

Lymphocyte Migration into Collagen Gels: Role of Lymph

In the present investigation we found that the presence of lymph within a 3-D collagen gel potentiates the invasion of mature recirculating lymphocytes into the gel. Preferential accumulation of lymphocytes in lymph-containing gels follows the sume rules that apply for both in vitro lymphocyte adhesion to high endotheltal venules of frozen sections of the lymph noues and in vivo lymph node entry of lymphocytes. Furthermore, the results obtained suggest that lymph is chemolacttc for lymphocytes. This chemoaltractant activity of lymph could be assigned mainly to a protein fraction precipitating in the. range of 40–60% concentration of ammonium sulphate. The biological significance of these findings for the selective process of lymphocyte emigration from blood to lymph, across the parenchyma of ihe nodes, is discussed.     

Immunosuppressive Effect of Cyclosporin A in Two Lymphocyte Transfer Models in Rats: Comparison of in Vivo and in Vitro Treatment

The immunosuppressive effect of CS-A was first studied in the assay for local GvHR. 3 x 10⁶ viable spleen cells from LEW rats were injected into one foot pad of LEW x BN hybrids and both PLN were weighed 7 days later. Treatment of the recipients with 3 doses of 50 mg/kg/day of CS-A suppressed this local GvHR. The effect was more pronounced when treatment started at the time of cell transfer rather than a few days before peak response. In-vitro incubation of the cellular inoculum with CS-A also prevented local GvHR. Histology of the PLN confirmed the quantitative results expressed by the PLN index. CS-A was further investigated in the EAE model in LEW rats. It protected rats sensitised with spinal cord emulsified in complete Freund's adjuvant for as long as they were treated with CS-A. Treatment delayed until after the appearance of EAE also markedly improved their condition. Oral treatment of recipients with 50 mg/kg/day CS-A prevented the development of adoptive EAE following the transfer of lymphoid cells conditioned in vitro. The presence of 0.1-1.0 μg CS-A in the medium of the sensitised lymphoid cells also inhibited the adoptive transfer of EAE. Finally, if the cells for the adoptive transfer were derived from CS-A-treated sensitised donors, they failed to induce EAE. Histological examination supported the symptomatic findings     

Role of Macrophages in Pregnancy and Related Complications

Archivum Immunologiae et Therapiae Experimentalis - Macrophages (MФs) are the leukocytes produced from differentiation of monocytes and are located in almost all tissues of human body. They...     

Role of Macrophages in Resistance to Murine Cytomegalovirus

The role of macrophages in protecting mice from murine cytomegalovirus (MCMV) was studied in Swiss, CBA/J, and C57BL/6J mice. CBA/J mice were more resistant to virus than were C57BL/6J mice at all ages tested. Prior treatment of adult Swiss mice with 60 mg of silica, a dose selectively toxic to macrophages, increased mortality due to MCMV infection. Transfer of syngeneic adult macrophages to suckling mice significantly increased their resistance to subsequent MCMV infection. Transfer of syngeneic, nonimmune adult lymphocytes to suckling mice also had a lesser but significant protective effect against subsequent MCMV challenge. In vitro infection of adult CBA/J and C57BL/6J macrophages with virulent and attenuated MCMV resulted in productive infection in only a small percentage of cells and recovery of very little virus from the extracellular fluid. Infection of CBA macrophages was no less productive than C57BL/6J nor was infection with virulent virus more productive than with attenuated virus. Histological examination of the livers of MCMV-infected CBA/J and C57BL/6J mice suggested that divergent cellular immune responses to infection might account for differences in susceptibility. It is postulated that the macrophage may facilitate the inductive phase of cellular immunity, one possible explanation for its demonstrated importance in host defenses against MCMV.     

Lymphocyte Transformation in Syphilis: an In Vitro Correlate of Immune Suppression In Vivo?

Suppression of cellular immunity during primary and secondary infection may explain, in part, the unusual clinical evolution of syphilis. We have previously shown that lymphocytes from normal subjects undergo blastic transformation when exposed in vitro to Treponema refringens. This response was suppressed in patients with syphilis. the suppression being unrelated to serum factors. In the present paper we studied lymphocyte response in vitro to T. refringens, T. reiter, and T. pallidum as well as to monilia and trychophytins. The response to these antigens was suppressed in patients with syphilis although the response to phytohemagglutinin. pokeweed mitogen, and streptolysin was normal. These data support the hypothesis that human infection with T. pallidum is followed by a complex interaction between cellular and humoral immunity, the former being suppressed in primary and secondary stages.     

Nod2 Mutation Enhances NF-kappaB Activity and Bacterial Killing Activity of Macrophages

NOD2, an intracellular sensor of bacteria, are linked to increased susceptibility to bacteria in Crohn’s disease (CD). The NOD2 protein is expressed mainly by macrophages and dendritic cells. This study is to examine the role of NOD2 in the innate response of macrophages to bacterial challenge. First, peritoneal macrophages and alveolar macrophages were harvested from WT, Nod2^2939iC, as well as TLR4^−/− mice and incubated with E. coli or P. aeruginosa. Bacterial killing activity; IL-1β and TLR4 protein expression; NF-κB DNA binding activity assay; as well as IL-1β, TNFα, TLR2, TLR4 and TLR9 mRNA expression of macrophages were examined. We found that alveolar macrophages and peritoneal macrophages of Nod2^2939iC mice but not WT mice or TLR4^−/− mice demonstrated a significant increase of E. coli killing activity. Bacterial challenge also induced a significant increase of pro-IL-1β protein expression; NF-κB DNA binding activity; as well as IL-1β and TNFα mRNA expression of the peritoneal macrophages in Nod2^2939iC mice. Collectively, the increase of bacterial killing activity, IL-1β expression, and NF-κB DNA binding activity of macrophages in Nod2^2939iC mice suggests that NOD2 is a positive regulator of NF-κB/IL-1β-mediated innate response to bacteria challenge in Crohn’s disease.     

Helminth Antigen Exposure Enhances Early Immune Control of Mycobacterium tuberculosis in Monocytes and Macrophages

Helminth and Mycobacterium tuberculosis (Mtb) coinfection is common and suggested to influence the risk of developing active tuberculosis (TB). It is known that helminths in contrast to TB induce a strong Th2 response in the host. However, the direct impact of helminth antigen exposure on host immunity against TB is largely unknown. Our aim was to explore the effects of helminth antigen exposure on the early immune control of Mtb in monocytes and macrophages. Ascaris lumbricoides (ASC) and Schistosoma mansoni (SM) protein antigens were used to study the immediate effect of helminth antigen exposure in monocytes, on monocyte-to-macrophage differentiation, or mature macrophages, in the control of virulent Mtb H37Rv. Pre-exposure of peripheral blood mononuclear cells reduced Mtb growth in monocytes, especially with SM, but no Th1/Th2 cytokines or activation markers indicated involvement of T cells. Monocytes exposed before maturing into macrophages reduced Mtb growth in macrophages (ASC), and pre-exposure of mature macrophages reduced (ASC) or kept Mtb growth at control levels (SM). This in vitro model shows how helminth infection directly affects the monocyte-macrophage axis at an early stage before cell-mediated immunity develops. During acute helminth coinfection or when helminth antigen concentration is elevated at the site of Mtb infection, these helminths provide an enhanced control and killing of Mtb owing to the direct stimulatory effect of helminth antigens on phagocytic cells.     

Induction of Reparative Dentinogenesis In Vivo: A Synthesis of Experimental Observations

EDTA—and/or guanidine HCl—insoluble dentinal matrix, or demineralized dentin which had been treated with plasma fibronectin, or pieces of Millipore filters coated with a recombinant fibronectin-like engineered polymer, incorporating many RGD sequences, were implanted into central parenchymal sites of young dog molars, via mechanical pulp exposures. Furthermore demineralized dentin and Millipore filters coated with plasma ribronectin were placed into the central pulp of old animals. Histological analysis of buffered formalin-fixed tissues showed that: 1. The dentinogenic activity was retained in the EDTA—and/or guanidine-insoluble dentin matrix. 2. Implantation of Millipore filters supplemented with the recombinant polymer did not induce any odontoblast-like cell differentiation, indicating that the interactions of pulp cells with the exogenous ribronectin are not RGD-dependent. 3. Acid-insoluble dentin matrix or plasma ribronectin (both separately inducing dentinogenesis in dental pulp of young animals) did not show any dentinogenic activity when exposed in pulp sites of old animals. Acid-insoluble dentin matrix and plasma ribronectin also failed to induce dentinogenic activity in the young pulpal tissues, when both factors were combined before to their implantation. Synthesizing the present data with previous relevant information it could be suggested that in the mechanism initiating reparative dentinogenesis. Growth factors (endogenous or artificially implanted) and ribronectin are involved and this mechanism seems to be more complex than the simple immobilization of pulp cells onto an adhesion substratum.