The formation and properties of macrophage polykaryons (inflammatory giant cells)

Detection of tumour necrosis factor alpha in sarcoidosis and tuberculosis granulomas using in situ hybridisation

AIMS

To determine the site of tumour necrosis factor alpha (TNF alpha) product and mRNA in granulomas.

METHOD

In situ hybridisation with digoxigenin labelled or biotinylated oligonucleotide probes was used to demonstrate the presence of total mRNA, and then the presence of TNF alpha mRNA in the biopsy specimens of 37 granulomas (31 sarcoidosis, six tuberculosis).

RESULTS

TNF alpha mRNA was detected in epithelioid cells, giant cells, and lymphocytes in the granulomas. Some sarcoidosis specimens did not contain detectable mRNA for TNF, but did contain TNF peptide in the epithelioid or giant cells on immunostaining. This may have been due to stored TNF present in cells in which mRNA for TNF is no longer being produced.

CONCLUSION

The results suggest that giant cells should not be regarded as effete cells, as they contain large amounts of mRNA and seem to be actively producing TNF alpha.

Ultrastructural interaction between multinucleate giant cells and the fungus in aspergillomas of human paranasal sinuses

The interaction between multinucleate giant cells (MGCs) and the fungus Aspergillus flavus as seen by transmission electron microscopy (TEM) is described in paranasal granulomas occurring in a Saudi patient dying from chronic aspergillosis. Two morphologically different types of MGCs were recognized; these were: a) 'Unhealthy looking' type I cells, rich in well organized organelles and containing few, partially degenerated and necrotic fungal elements. b) 'Healthy looking' type II cells that contained scanty, randomly dispersed cell organelles and normal, or partially degenerated fungal hyphae. The fungal elements had very thick and multilayered cell walls, and were found either in close contact to the host cell cytoplasm, or enclosed within phagosomes. The mechanism of the fungus destruction by the host MGCs is described and compared with that previous reports of MGCs involved in the elimination of extracellular microorganisms. The morphology and the various physiological activities of MGCs seems to depend mainly on whether the pathogen is extra- or intracellular. However, this study showed that MGCs are the cells best suited for killing pathogenic fungi.

Osteoclastic resorption of Ca-P biomaterials implanted in rabbit bone

The nature of the multinucleated cells involved in the resorption processes occurring inside macroporous calcium-phosphate biomaterials grafted into rabbit bone was studied using light microscopy, histomorphometric analysis, enzymatic detection of tartrate-resistant acid phosphatase (TRAP) activity, scanning, and electron microscopy. Samples were taken at days 7, 14, and 21 after implantation. As early as day 7, osteogenesis and resorption were observed at the surface of the biomaterials, inside the macropores. Resorption of both newly formed bone and calcium-phosphate biomaterials was associated with two types of multinucleated cells. Giant multinucleated cells were found only at the surface of the biomaterials; they showed a large number of nuclei, were TRAP negative, developed no ruffled border, and contained numerous vacuoles with large accumulation of mineral crystals from the biomaterials. Osteoclasts exhibited TRAP positivity and well-defined ruffled border. They were observed at the surface of both newly formed bone and biomaterials, around the implant, and inside the macropores. In contract with the biomaterials, infoldings of their ruffled border were observed between the mineral crystals, deeply inside the microporosity. The microporosity of the biomaterials (i.e., the noncrystalline spaces inside the biomaterials) increased underneath this type of cell as compared with underneath giant cells or to the depth of the biomaterials. These observations demonstrate that macroporous calcium-phosphate biomaterials implanted in bone elicit osteogenesis and the recruitment of a double multinucleated cell population having resorbing activity: giant multinucleated cells that resorb biomaterials and osteoclasts that resorb newly formed bone and biomaterials.

Leukocyte-deactivating factor from macrophages: partial purification and biochemical characterization. A novel cytokine

A deactivating factor (MDF) is released from granuloma-like lesions of mice (giant and epithelioid macrophages) to the surrounding medium. Test cells incubated in the presence of MDF display dramatic inhibition of superoxide anion (O2-) release when stimulated. This failure to manifest O2 release is observed whether PMA, all-transretinal, or fMet-Leu-Phe is the stimulating agent. MDF acts on different cell types from different species; mouse macrophages as well as guinea pig, human, and mouse neutrophils. Such results suggest that it is a universal regulatory cytokine with high affinity for phagocytic lineages. The factor was subjected to various purification methods: ultrafiltration, gel chromatography, and reversed phase HPLC. A crude preparation that resulted from conditioning of medium by old macrophages (MCM) shows two peaks of activity when subjected to gel filtration. These correspond to molecular weights for the active principle of 3 and 11 kD. When the factor was obtained by extraction of the same cells after washing and sonication, only the former peak was seen. Fractions corresponding to a MW of 3 kD from several preparations were combined and subjected to HPLC. MDF activity then appeared in a single fraction. MDF is thus putatively a modulator of the cidal activity of phagocytic cells that utilize release of reactive oxygen species for cytocidal activity.

Haematological changes associated with miliary tuberculosis of the bone marrow

The peripheral blood and bone marrow findings in 25 patients found to have tuberculous granulomata on bone marrow examination were examined to determine whether specific haematological findings are associated with tuberculous infiltration of the bone marrow. All the patients had one abnormality or more on their full blood count. The presence of a peripheral lymphopaenia was the single factor common to all 25 patients studied. The peripheral lymphopaenia was only associated with bone marrow lymphopaenia in 14% of patients. Other findings of note were an association of peripheral monocytopaenia and absence of giant cells in the granulomata, and decreased iron stores in almost a third of the total number of patients. The relevance of the lymphopaenia, monocytopaenia and decreased iron stores are discussed and we propose that the absence of a peripheral lymphopaenia makes it very unlikely that there will be tuberculous localization in the bone marrow.

Treatment outcomes for temporomandibular joint reconstruction after Proplast-Teflon implant failure

A retrospective study of 107 patients (male, n = 13; female, n = 94) with 163 joints previously treated with Proplast-Teflon (PT; Vitek, Inc, Houston, TX) implants was performed. The average time in situ for the PT was 59.8 months (range, 2 to 126 months). Average length of follow-up was 84.6 months (range, 59 to 126 months). Only 12% of joints showed no significant osseous changes radiographically. Forty-five patients (42%) continue to have in situ PT implants and 36% of them experience pain that requires medication; 25% have developed an anterior open bite and malocclusion; 9% have limited vertical opening; and 40% are asymptomatic. Temporomandibular joint (TMJ) reconstruction after PT implant failure was performed with five different autologous tissues or a total joint prosthesis. Autologous tissues used to reconstruct the TMJ and the rates of success were as follows: 1) 31% free temporalis fascia and muscle graft with and 13% without sagittal split ramus osteotomy, 2) 8% dermis, 3) 25% conchal cartilage, 4) 12% costochondral grafts, and 5) 21% sternoclavicular grafts. The success rate decreased in all autologous tissue groups as the number of TMJ surgeries performed before reconstruction increased. Ankylosis was the most common cause of failure. Results of TMJ reconstruction with a total joint prosthesis were as follows: 1) 88% functional and occlusal stability of total joint prosthesis; 2) level of pain reduction was rated as 46% good, 38% fair, and 16% poor; and 3) an average interincisal opening of 27 mm at 24 months or less, and 33 mm at 25 months and beyond.(ABSTRACT TRUNCATED AT 250 WORDS)

Time course of lipid-laden pulmonary macrophages with acute and recurrent milk aspiration in rabbits

High levels of lipid-laden macrophages (LLM) in bronchial washings have been associated with food aspiration. We studied the time course of appearance and clearance of LLM in rabbits undergoing either a single milk instillation, five weekly milk instillations or saline (control) instillations into the airways. Cells were obtained by bronchoalveolar lavage of intubated rabbits at uniform time intervals following the single or the last of five milk/saline instillations. LLM semi-quantitative indexes were derived using oil-red-O staining. Significantly elevated indexes were found in both milk groups 6 hr after milk instillation. In the single saline and milk instillation groups the indexes were not different beginning on the 4th day, and indexes from 8 of 9 rabbits had returned to baseline by the 6th day. However, indexes remained significantly elevated up to 17 days in the group receiving weekly milk instillations. Indexes from all rabbits in the repeat milk instillation group remained elevated for 12 days or longer. This group also developed increased numbers of binucleated macrophages. Quantitation of LLM in this model appears to be a sensitive indicator of recurrent lipid aspiration, these cells remaining in the airways for several days after the last aspiration event.

Induction of multinucleated giant cell formation from in vitro culture of human monocytes with interleukin-3 and interferon-gamma: comparison with other stimulating factors

One of the hallmarks of the granulomatous response to infection is the formation of multinucleated giant cells (MGC.) In an effort to study MGC, we examined the fusion-promoting effects of a variety of stimulating factors on human peripheral blood monocytes cultured on plastic surfaces in serum-supplemented media. MGC formation was minimally to moderately enhanced by interferon-gamma (IFN-gamma), interleukin (IL)-3, granulocyte/macrophage colony-stimulating factor (GM-CSF), 1,25-dihydroxycholecalciferol (1,25-(OH)2D3), retinoic acid (RA), and IL-6. IL-4 (which has been reported to promote MGC formation from murine macrophages) had an inhibitory effect. IFN-gamma was not required for MGC formation but it significantly increased the fusion-promoting activity of GM-CSF, 1,25-(OH)2D3, RA, and IL-6, IL-3, a hematopoietic growth factor, has been recently shown to induce osteoclast formation from murine bone marrow mononuclear cells. The most striking effect was seen with the combination of IL-3 and IFN-gamma. Fusion index is defined as a percentage of nuclei found within MGC, and an index of 67% at 1 wk was found. The formation of some very large cells with 50 to 100 nuclei was noted. Both Langhans' and foreign-body type cells were seen. Transmission electron micrographs clearly demonstrate the absence of plasma membrane between nuclei. Induction of MGC from peripheral human blood monocytes by IL-3 and IFN-gamma provides an in vitro system for the study of the formation and function of these cells.

Monoclonal antibody AMH152 reacts with human monocytes in culture and with inflammatory macrophages

Monoclonal antibodies (mAb) raised against human peritoneal macrophages were selected for their non-reactivity with freshly sampled blood cells. One of these mAb, AMH152, initially non-reactive, bound to monocytes after 18 h of culture, a property which was not shared by an unrelated antibody of the same isotype (IgG1). The induction of the expression of the antigen detected by AMH152 on monocytes in culture was not influenced by the addition of serum or by the substrate used, plastic that favoured adhesion or teflon bags. Overnight incubation at 4 degrees C in adhesion conditions did not enable antigen expression. A 1-h treatment with phorbol myristate acetate or formyl-methionyl-leucyl-phenylalanine did not increase AMH152 binding. Culturing monocytes with cycloheximide tended to inhibit antigen expression. These observations suggested that antigen expression represents an active phenomenon, requiring protein synthesis. The antigen recognized by mAb AMH152 could be visualized on sections of formalin-fixed and paraffin-embedded tissues. Macrophages of healthy lymphoid organs and tissues that expressed CD68 antigen failed to bind AMH152. In contrast, chronic inflammatory lesions, like those of sarcoidosis, tuberculosis and cat scratch disease, contained epithelioid and multinucleated giant cells that reacted with AMH152. In serous exudates of cancer metastases, 10-40% of macrophages were also stained. The antigenic material was essentially present at the cell periphery. Thus, mAb AMH152 recognized a surface antigen, detectable on paraffin-embedded tissue sections, and which accompanied differentiation of monocytes into inflammatory cells. The expression of this antigen on monocytes in culture suggests that these cells underwent an activation process, even when maintained for some hours in teflon bags and in a serum-free medium.

The biologic responses to orthopedic implants and their wear debris

The use of artificial materials in the treatment of orthopaedic conditions, most notably arthritis, over the past few decades has been increasing dramatically. Such use makes an understanding of the tissue responses to the various materials necessary to determine their effectiveness and acceptability. This review concentrates on the studies of the biological responses to the materials that are used mainly in joint replacements and fixation of fractures. In-vivo and in-vitro experimental studies of various metals, polymers and ceramics and their constituents are first presented with discussions regarding their clinical importance. Studies of clinically successful implants are then presented to illustrate the expected morphological features of incorporation and acceptance by the host tissues. The local and systemic effects complicating the use of the implanted materials as well as the failure of the implant are then presented.

Extracellular matrix receptor and platelet antigens on osteoclasts and foreign body giant cells

Osteoclasts (OCs) and other cells of the mononuclear phagocyte system possess receptors for adhesive proteins present in the extracellular matrix. The antigenic phenotype of OCs and foreign body giant cells (FBGCs) was investigated for the presence of several integrin molecules and other largely platelet-associated antigens involved in cell adhesion reactions. Both OCs and FBGCs expressed the alpha-chains of the vitronectin receptor (CD51) and of the VLA-2 (CDw49b) and VLA-4 (CDw49d) molecules as well as their respective beta-chains, gpIIIa (CD61) and CD29. OCs and FBGCs also expressed CD9 and CD55 (DAF-Decay Accelerating Factor) and strongly reacted with antibodies directed against fibrinogen, fibronectin and vitronectin; the latter are ligands for several of the above matrix protein receptors. The data suggest that cell-cell and cell-matrix interactions involving adhesive proteins may be important in OC and FBGC function.

A role for osteocalcin in osteoclast differentiation

Specific cellular interactions with components of the extracellular matrix can influence cellular differentiation and development of many tissues. The extracellular matrix of bone is composed of organic constituents and a solid phase of calcium and inorganic phosphate (apatite). When implanted subcutaneously in rats, particles of bone matrix (BPs) recruit progenitors that differentiate into multinucleated cells with osteoclastic features. Because BPs deficient in osteocalcin, a bone matrix protein, were less efficient at promoting osteoclast formation than were normal BPs, we directly examined the influence of osteocalcin on osteoclast differentiation. We evaluated tissue responses to particles of synthetic crystalline apatite alone (Ap), having many of the features of native apatite of mature bone, or to apatite prepared with osteocalcin (Ap/OC), bovine serum albumin (Ap/BSA) or rat bone collagen (Ap/Col). Twelve days after subcutaneous implantation in normal rats, Ap, Ap/BSA, and Ap/Col particles generated a mild foreign body reaction with multinucleated cells in direct contact with the particles; these cells were negative for tartrate-resistant acid phosphatase (TRAP) activity and lacked ruffled borders. In contrast, Ap particles containing approximately 0.1% osteocalcin were partially resorbed and they generated more multinucleated cells that were TRAP-positive, were immunoreactive with an antibody against tartrate-resistant purple acid phosphatase, and displayed ultrastructural features of active osteoclasts including ruffled borders and clear zones. These data support the hypothesis that osteocalcin may function as a matrix signal in the recruitment and differentiation of bone-resorbing cells.

In vivo degradation of processed dermal sheep collagen evaluated with transmission electron microscopy

The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could be distinguished. In addition to normal components of a typical foreign body reaction, remarkable phenomena, such as locally deviant neutrophil morphology, infiltration of basophil-like cells, indications of foreign body multinucleate giant cells formed from different cell types, aluminium silicate accumulations and calcium phosphate depositions, were observed. Foreign body multinucleate giant cells intracellularly degraded hexamethylenediisocyanate-tanned dermal sheep collagen after internalization. Both internalized and cellularly enveloped hexamethylenediisocyanate-tanned dermal sheep collagen degraded by the detachment of fibrils. Another extracellular route of degradation was characterized by calcium phosphate depositions in large bundles of hexamethylenediisocyanate-tanned dermal sheep collagen. From 6 wk, the hexamethylenediisocyanate-tanned dermal sheep collagen implant was replaced by rat connective tissue, which was subsequently also degraded. After 15 wk, the presence of basophil-like foreign body multinucleated giant cells containing aluminium/silicon-crystalline accumulations still persisted. These phenomena were related to the specific nature of the material used and suggest cytotoxicity. They emphasize the need for detailed evaluation at the ultrastructural level of newly developed biomaterials before they can be used for medical applications.

Establishment of murine macrophage-like mutant and hybrid cell lines: comparative analysis of the differentiation induced by 1 alpha,25-dihydroxyvitamin D3 and recombinant murine interferon-gamma

The purpose of this study is to establish the monocyte/macrophage-like cell lines which are sensitive to potent systemic and local factors, 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2 VD3) and interferon-gamma (IFN-gamma). We established two variant mouse macrophage-like cell lines, whose responses to 1 alpha,25(OH)2 VD3 and IFN-gamma differed from one another. The AH-sensitive mutant cell line (G3) was induced by allowing P388D1 tolerant to 8-azaguanine. G3 mutant cells were then fused with the 1 alpha,25(OH)2 VD3-stimulated bone marrow cells isolated from DBA/2 mice. After AH selection the hybrid cell line (XC) was established. The G3 mutant cell line and the XC hybrid cell line had macrophage-like characteristics, such as surface antigens, Fc receptor, C3 receptor, and lysosomal enzymes. The treatment of G3 mutant cells with 1 alpha,25(OH)2 VD3 inhibited cell proliferation with morphological changes, and increased acid phosphatase activity, phagocytic activity, and F4/80 antigen expression on the cell surface. In contrast, IFN-gamma inhibited cell proliferation without effect on acid phosphatase activity and phagocytic activity but increased F4/80 antigen expression. In XC hybrid cells, on the other hand, IFN-gamma, but not 1 alpha,25(OH)2 VD3, inhibited cell proliferation with morphological changes but increased phagocytic activity and F4/80 antigen expression. In addition, IFN-gamma, but not 1 alpha,25(OH)2 VD3, dose-dependently increased multinucleated cell formation of both cells. These findings suggest that the G3 mutant cell line with macrophage-like characteristics is 1 alpha,25(OH)2 VD3- and IFN-gamma-sensitive, and that the XC hybrid cell line is, despite its macrophage-like characteristics, only IFN-gamma-sensitive. Therefore, these newly established cell lines will provide useful systems in studying the differentiation of monocyte/macrophage lineage.

Granulomatous inflammation and monstrous giant cells in response to intraperitoneal hormone implants in channel catfish (Ictalurus punctatus)

Plastic implants (2.7 mm maximum dimension) of an ethyl vinyl acetate copolymer (EVAc) matrix, containing inulin, bovine serum albumin (BSA) and luteinizing hormone releasing hormone (LHRH), were covered with impervious EVAc and then surgically placed into the peritoneal cavity of 1-year-old channel catfish, Ictalurus punctatus. In fish kept in cold water (13 degrees C), 10 per cent of the implants per month were encapsulated by granulation tissue. In fish kept in warm water (27 degrees C), 20 per cent of the implants per month were encapsulated, with a total of 86 per cent encapsulated at 5 months. In addition to fibroblasts and capillaries, the granulation tissue included macrophages, neutrophils, lymphocytes, plasma cells, multinucleated giant cells and a matrix of collagen fibres. The density of the fibrous capsule increased with time. In a separate investigation, it was found that the thickness of the capsule was directly proportional to the degree of exposure of the EVAc matrix to the fish (exposure influenced by the rate of dissolution of the capsule content). Monstrous giant cells with up to 600 nuclei per 5 microns thick section were seen in capsules around implants. On intraperitoneally implanted cover glasses, whole giant cells contained up to 6000 nuclei and were interconnected by cytoplasmic bridges. Signs of neoplasia, implant expulsion or massive adhesions were not seen.

Immunophenotypic differences between osteoclasts and macrophage polykaryons: immunohistological distinction and implications for osteoclast ontogeny and function

The antigenic phenotype of human fetal osteoclasts was compared with that of human tissue macrophages and macrophage polykaryons in foreign body lesions using a large number of monoclonal antibodies directed against myeloid (granulocyte/mononuclear phagocyte) antigens. Osteoclasts expressed a restricted range of macrophage-associated antigens including CD13, CD15A, CD44, CD45, CD54, (ICAM-1), CD71 (transferrin receptor), and CD68. These antigens were also present on macrophages and macrophage polykaryons both of which also strongly expressed CD11a,b,c, CD18, (LFA family), CD14, CD31, CD36, CD37, CD39 and CD43 antigens. There was also weak and occasional expression of CD16 (FcRIII), CD25 (interleukin 2 receptor), CD32 (FcRII), CD35 (C3b receptor) and HLA-DR by macrophage polykaryons. The presence of some macrophage associated antigens on osteoclasts is consistent with their originating from cells of the mononuclear phagocyte system. The numerous differences in antigenic phenotype between osteoclasts and macrophage polykaryons, however, suggest that their pathways of development and differentiation are not identical. The differences discerned in antigenic phenotype should also permit distinction between these polykaryons (and possibly their mononuclear precursors) in normal and diseased tissues.

Epithelial macrophages secrete a deactivating factor for superoxide release

The release of superoxide anion (O2-) by inflammatory macrophages, multinucleated giant cells, and epithelioid cells, obtained by the insertion of round glass coverslips into the subcutaneous tissue of mice, was investigated. O2- was shown to be spontaneously released by cells on the surface of glass coverslips implanted up to 7 days, but not by cells obtained 14 or 21 days after coverslip implantation. The former showed increased O2- release when stimulated by phorbol myristate acetate, whereas cells harvested after 14 or 21 days implantation did not. The induction of delayed type hypersensitivity around coverslips implanted for 5 days increased spontaneous O2- release by these cells by 40%. On the other hand, when the same protocol was used with coverslips implanted for 14 days, O2- release was not detected. These results were viewed in regard to the composition of the cell population at each time point. When coverslips were removed after 14 days of implantation and the cells incubated for 30 minutes in vitro, the medium so conditioned inhibited O2- release by cells of 5 day old preparations. This indicates the release by cells on the longer term coverslips of a substance that inhibits O2- production by cells of coverslips implanted for 5 days only. This inhibitory activity could be suppressed by treating the conditioned medium with proteases. The factor was, however, heat stable and exerted its effects even when the test cells were exposed to phorbol myristate acetate.

Anti-RMA, a murine monoclonal antibody, activates rat macrophages: II. Induction of DNA synthesis and formation of multinucleated giant cells

Anti-RMA is a murine anti-rat monoclonal antibody that binds to a 120-kD surface membrane antigen expressed primarily by alveolar macrophages. Saline-lavaged alveolar macrophages (AM) formed clusters after incubation with anti-RMA. Anti-RMA produced multinucleated giant cells (MGC) in approximately 15% of adherent AM, and the F (ab')2 fragment of anti-RMA yielded MGC in approximately 9% of AM. The Fab fragment of anti-RMA did not promote MGC formation, nor did the murine anti-rat monoclonal antibodies OX41 and W3/25 (anti-CD4). Although anti-RMA produced a tenfold increase in [3H]thymidine incorporation by AM, it yielded a minimal increase in the number of AM. Autoradiography of AM stimulated with anti-RMA showed heterogeneous labeling of nuclei in MGC, suggesting that 3H-labeled AM may fuse with AM that are not actively synthesizing DNA. These findings suggest that binding of anti-RMA to AM may activate DNA synthesis, and promote clustering and fusion of AM, leading to MGC formation.

Cytokine-induced generation of multinucleated giant cells in vitro requires interferon-gamma and expression of LFA-1

Multinucleated giant cells (MGC), which are a common feature of various pathologic states, were generated in vitro by cytokine-stimulation of human peripheral blood monocytes. As expected, conditioned medium, i.e. the supernatant of concanavalin A-stimulated peripheral blood mononuclear cells, readily caused generation of MGC. Addition of a monoclonal antibody (mAb) against interferon-gamma (IFN-gamma) completely abrogated this effect. IFN-gamma alone, however, had a much smaller effect than the conditioned medium. All other cytokines tested [including interleukin (IL)2, IL4 and tumor necrosis factor-alpha, which are known to activate monocytes] did not induce MGC nor did they enhance the effect of IFN-gamma. Formation of MGC could almost entirely be inhibited by mAb to the alpha or beta chain of LFA-1 and to a lesser extent by relatively high concentrations of a mAb against ICAM-1, one of the ligands of LFA-1. In contrast to the anti-IFN-gamma mAb that had no significant effect on the formation of monocyte clusters, mAb against LFA-1 inhibited clustering very efficiently. Antibodies directed to a number of different antigens present on the surface of monocytes (alpha chains of CR3 and CR4, HLA class I and II molecules, CD14 and CD16 antigens) had little or no effect on the generation of MGC. IFN-gamma, but not the concanavalin A-induced supernatant clearly enhanced expression of LFA-1 and ICAM-1 on monocytes. The results indicate that cytokine-induced generation of MGC is not possible without IFN-gamma, but most probably additional factor(s) enhance this effect. The mechanism(s) by which IFN-gamma promotes monocyte fusion apparently includes, among others, up-regulation of LFA-1 whose expression seems to be necessary but not sufficient for fusion.

Extramedullar proliferation of eosinophil granulocytes in chronic schistosomiasis mansoni is mediated by a factor secreted by inflammatory macrophages

In chronic murine schistosomiasis mansoni, extramedullar myelopoiesis of eosinophils has been described, associated with tissue inflammatory infiltrates and periovular granulomas. It may be experimentally induced by intraperitoneal glass implants in mice with chronic schistosomiasis but not in normal mice or in mice with acute schistosomiasis. In vivo studies showed that this induction depended on macrophages adherent to the implants. In an in vitro test with bone marrow cells, we demonstrated that this eosinophil proliferation was mediated by a factor secreted by the mobilized macrophages. In contrast to murine interleukin-5 (IL-5), which induced both proliferation and differentiation of eosinophils, the studied monokine did not induce their maturation. A potent neutralizing monoclonal antibody for murine IL-5 did not abrogate the stimulatory activity of the monokine, indicating that it is a cytokine distinct from IL-5. These data, together with a quantitation of bone marrow, blood, and peripheral eosinophils, indicated that in chronic schistosomiasis, the systemic medullar supply of eosinophils is supplemented in tissues by their local proliferation, mediated by macrophages mobilized in local granulomatous and diffuse inflammatory reactions.

Morphologic characterization of alveolar macrophages from subjects with occupational exposure to inorganic particles

Alveolar macrophages recovered by bronchoalveolar lavage from 43 nonsmoking or greater than 5-yr ex-smoking subjects with occupational exposure to inorganic particles (asbestos, n 1/2 19; silica, n 1/2 10; coal, n 1/2 14) were evaluated by light microscopy and transmission and scanning electron microscopy to determine the morphologic changes resulting in these cells from chronic inorganic particulate inhalation. Alveolar macrophages from dust-exposed subjects, including those who had been free of exposure to particles for more than 1 yr, contained particles of higher proportion than did those of normal unexposed subjects. Most of these particles were located within phagolysosomes. The frequency of multinucleated alveolar macrophages was significantly higher in the dust-exposed groups. Ultrastructural studies showed alterations of the morphologic aspects of the surfaces of alveolar macrophages from the dust-exposed subjects, including increased numbers of rufflings, filopodia, pinocytotic vesicles, subplasmalemmal linear densities, and increased frequency of macrophage-macrophage and macrophage-lymphocyte interactions. Furthermore, the numbers of lysosomes were significantly increased in alveolar macrophages from the dust-exposed subjects. Together, these morphologic changes are consistent with the sequelae of phagocytosis, and they emphasize both the role of alveolar macrophages in eliminating inorganic particles from the alveolar spaces and the consequences this role has in alveolar macrophage activation.

Cytopathology of early cellular reaction on implant lenses in monkeys. A transmission electron microscopic study

We carried out extracapsular lens extraction with the implantation of a modified C-loop posterior chamber lens in eight monkey eyes. The animals were killed after varying survival of up to 14 days. The intraocular lenses (IOLs) were removed and examined by transmission electron microscopy. Three different types of cells, namely, polymorphonuclear leukocytes, macrophages, and multinucleated giant cells, were observed on the surface of the IOLs. A thin, membrane-like structure composed of finely granular material covered the lens surface. These cell components were not attached directly to the lens surface, but, rather, were located on the membrane-like structure.

Macrophages: current views on their differentiation, structure, and function

Macrophages are large mononuclear phagocytes that represent the major differentiated elements of the mononuclear phagocytic system. They arise from distinct progenitors in the bone marrow, and their immediate precursors, the monocytes, emigrate from the vascular compartment into many tissues and organs where they develop into mature macrophages. The latter display diverse morphological and functional characteristics, depending on the environmental stimuli that they receive. This phenotypic heterogeneity is, therefore, the final consequence of a series of down-regulation of some cellular processes and the up-regulation of others. The kinetics of the production of macrophages and their participation in various physiological and pathological phenomena is the subject of this review.

Effects of bone matrix components on osteoclast differentiation

When implanted subcutaneously in rats, devitalized bone particles (BP) elicit the differentiation of osteoclastic cells. Those cells can be distinguished from foreign body giant cells that form in response to particulate plastics. Osteoclast features include resorption of the bone substrate, ruffled borders, calcitonin receptors, tartrate-resistant acid phosphatase activity, and modulation by bone active agents. To determine whether expression of these features depends on specific components of the matrix, we characterized the multinucleated cells that developed in response to osteocalcin-deficient BPs, particulate microcrystalline hydroxyapatite (HA), and HA containing 0.1% osteocalcin, collagen, or bovine serum albumin. Only those particles that contained mineral and osteocalcin were associated with osteoclastic cells. These studies support the hypothesis that osteocalcin may function as a matrix signal in the differentiation of osteoclasts.

Occurrence of multinucleated giant cells in the appendix of clinically healthy rabbits

The spontaneous formation of multinucleated giant cells was observed in the appendix of clinically healthy adult rabbits that were free of infection with intestinal viruses, pathogenic bacteria, fungi and parasites. Giant cells occurred singly and in aggregates. They were of the foreign body and of the Langhans' type, but intermediate forms were also noticed. Ultrastructurally, the hallmark of these appendiceal polykaryons were large phagolysomal fields harbouring amorphous debris and remains of cytoplasmic organelles and bacteria. The bacteria in the appendiceal tissues were neither of a special type nor acid-fast. The aetiology and significance of appendiceal giant cells remains to be clarified.

The effect of tamoxifen and medroxyprogesterone on giant cell formation by monocytes from patients with breast cancer

Incubation of peripheral blood monocytes from patients with breast cancer under agarose for 6 days at 37 degrees C in a 5% CO2 atmosphere resulted in giant cell formation. This phenomenon appeared to be mediated by retroviruses present in these cells. In this study giant cell formation was investigated in patients with primary stage I and II breast cancer before and 3 months after mastectomy with axillary lymph node clearance. Mastectomy had no significant inhibitory effect on giant cell formation. In vitro incubation of monocytes from patients with breast cancer in the presence of tamoxifen (Nolvadex) resulted in significant inhibition of giant cell formation (P less than 0.000003; paired Student's t-test). In vitro addition of medroxyprogesterone (Farlutal) to monocytes from patients with breast cancer also resulted in significant inhibition of giant cell formation (P less than 0.003: paired Student's t-test). Furthermore, incubation of monocytes from patients treated by mastectomy followed by 3 months treatment with adjuvant tamoxifen, resulted in a significant reduction (P less than 0.00007; paired Student's t-test) in the number of giant cells compared to the same samples tested before the commencement of the treatment. Giant cell formation may be used as a simple test to predicte the response of patients with breast cancer to either tamoxifen or medroxyprogesterone.

Multinucleated cells elicited in response to implants of devitalized bone particles possess receptors for calcitonin

The introduction into soft tissues of particulate materials resistant to digestion results in the induction of a "foreign-body giant-cell reaction." We have examined the relation between osteoclasts and foreign-body giant cells by comparing the tissue responses elicited by subcutaneous implants of devitalized, mineral-containing bone particles (BP), nonresorbable plastics such as polymethylmethacrylate (PMMA), or both. Implantation of BP results in the recruitment of multinucleated cells with features of in osso osteoclasts including tartrate-resistant acid phosphatase activity, contact-mediated resorption of BP, membrane specializations (ruffled borders and clear zones), and inhibition of resorption by calcitonin treatment of animals. In the present study, an autoradiographic technique employing 125I-salmon calcitonin was used to demonstrate the presence of receptors for this hormone on multinucleated cells from BP implants. In contrast, outgrowth cells from PMMA implants lacked calcitonin receptors. Demonstration of features of the osteoclastic phenotype in multinucleated cells elicited in response to BP supports the hypothesis that the mineralized matrix of bone may be a requirement for acquisition of the osteoclast phenotype.

Interleukin 4 induces cultured monocytes/macrophages to form giant multinucleated cells

Giant multinucleated cells (GMCs) are associated with granulomatous lesions that form in response to various infectious and noninfectious agents. The present study shows that mouse IL-4 induces the in vitro formation of GMCs by factor-dependent bone marrow and alveolar monocytes via cell fusion. GMCs appear 2 d after incubation of cell cultures with 20 U/ml or more of IL-4. Anti-IL-4 mAbs block the appearance of GMCs in these cultures, indicating that IL-4 acts directly on monocytes to promote fusion and does not secondarily induce the production of other soluble fusion factors. In soft agar cultures, IL-4 also causes the aggregation of macrophages and diminishes their migration. The role of IL-4 in a granulomatous inflammatory response is discussed.

In vitro and in vivo interactions of cells with biomaterials

The biocompatibility of materials at an implant site involves a complex interaction of cells and tissues with the biomaterial. This cell-cell and cell-polymer interaction evokes the release of mediators such as chemotactic and growth factors that elicit and sustain inflammatory responses at the implant site. In this review, we summarize the interaction of cells with biomaterials in vitro and in vivo.

Nuclear bridges within multinucleated giant cells in subacute encephalitis of acquired immune deficiency syndrome (AIDS)

Six cases of subacute encephalitis in AIDS were examined with special reference to the nuclear morphology of multinucleated giant cells (MGC's). Although rare in some, all cases showed nuclear bridges which were thin strands connecting individual nuclei. Even more frequently observed were nuclear processes which were probably parts of nuclear bridges or disconnected ends of nuclear bridges. Nuclear bridges and processes were not features of mitosis but were composed of nucleoplasm. They appear to be a feature of MGC's in AIDS but may not be limited to this condition.

Subcutaneous fat necrosis of the newborn with emphasis on ultrastructural studies

The morphologic examination of neonatal subcutaneous fat necrosis is reported. Subcutaneous nodules after prolonged labor and asphyxia appeared in the skin of the back and neck. Biopsy was performed at 16 days. The infants' general state did not change and the nodules spontaneously regressed. Light microscopically focal necroses of the subcutaneous adipose tissue were present, with granulation tissue. Electron microscopy revealed complex material replacing the necrotic fat cells. Two types of crystals could be observed: short, rectangular ones irregularly arranged and long, needle-shaped ones, parallel or radial in arrangement. The dissolved lipid crystals were surrounded by membranes that probably arose from the necrotic fat cells. The crystals passed the cytoplasm membrane of the macrophages. Giant cells arose from macrophages, partly by fusion of the cells and partly by amitosis.

Is cancer a macrophage-mediated autoaggressive disease?

As part of their physiological functions macrophages secrete various products that influence tissue environment. They can also secrete tumour growth promoting substances and it is highly probable that they help to establish tumour supporting fibrovascular stroma. Macrophages may fuse with other cells (including neoplastic cells) and many malignant properties of these hybrids or of their progeny may be maintained by the macrophage genome. In addition processes that occur after fusion might be important in inducing malignant transformation, especially when fusion has occurred with initiated cells. Superficial spreading melanoma is an example that is in keeping with the hypothesis of cell fusion.

Macrophages, macrophage foam cells, and eccentric intimal thickening in the coronary arteries of young children

We surveyed the incidence and location of macrophages and macrophage foam cells in the coronary artery intima of 63 children that died in the first 5 years of life. We related the data on macrophages and macrophage foam cells to intimal smooth muscle cells and to measurements of intima:media area and thickness. All morphometric data were obtained from coronary arteries that were fixed by perfusion with glutaraldehyde under pressure, embedded in Maraglas, and cut into 1-micron cross-sections, and 65-nm fine sections. Coronary artery intima was always thicker (eccentric thickening) at bifurcations in the half of the circumference opposite to the flow divider. This was true for both male and female children. The remaining part of the coronary artery intima was less thick (diffuse thickening). Both types of intimal thickening were composed of an inner layer in which glycosaminoglycan ground substance predominated and a deeper musculoelastic layer. Fifty-nine children (94%) had intimal macrophages. Twenty children also had macrophage foam cells. Of 33 children aged to 8 months, 15 (45%) had macrophage foam cells. Of the 30 children older than 8 months, 5 (17%) had macrophage foam cells. Macrophages and macrophage foam cells occurred in the GAG-rich layer of the intima as isolated cells. In 5 infants macrophage foam cells occurred also as clusters of many cells. Macrophages were more numerous in cases that also had macrophage foam cells. Macrophages were 6 times, and macrophage foam cells 5 times more numerous in eccentric intimal thickening than in diffuse intimal thickening.

Origin, fate, and properties of multinucleated giant cells and their association with milk-synthesizing tissues of the bovine mammary gland

Histological study of multinucleated giant cells (MGC) in bovine mammary glands demonstrated that the cells predominated during mammary involution. Concentrations of MGC increased from the early to later stages of involution, and were more prevalent in older cows. There was no association between infection status and prevalence of MGC. A study of the relationship between MGC and other components of the mammary parenchyma indicated that these cells formed in response to substances that accumulated in mammary secretions during involution. MGC appeared to play a role in resorption of insoluble milk constituents, and removal of amyloid and effete macrophages.

Effect of some endodontic sealers on cell migration in experimental granulomas

CRCS or calciobiotic root canal sealer (a calcium hydroxide-based sealer), Proco-sol and Tubliseal (both zinc oxide eugenol-based sealers), and Diaket-A (a polyvinyl-based sealer) were assessed for their relative cytotoxicities by their different cell migration effects by means of glass coverslip granulomas. Cytotoxicity was assessed by means of the influx of mononuclear cells or macrophages and their transformation into multinucleate giant cells. CRCS was shown to be the best sealer, followed by Proco-sol and Tubliseal. Diaket-A was the most cytotoxic of the sealers tested.

Transformation of blood monocytes to giant cells in vitro from patients with breast cancer

Monocytes from patients with breast cancer and from control subjects were cultured under agarose for 6 days. Giant cell formation occurred in 32 out of the 36 patients with breast cancer (89 per cent). In contrast giant cell formation was only observed in two of the control subjects (6 per cent). Menstruation and menopause had no effect on giant cell formation. Furthermore, under the experimental conditions of this study, it seems unlikely that serum factors, lymphokines or phagocytic stimulators induced giant cell formation. The results therefore, suggest that giant cell formation may be initiated by viruses already present in the monocytes from patients with breast cancer. Further studies are required to confirm this hypothesis and to elucidate the significance of giant cell formation in the pathogenesis of breast cancer.

Comparison of multinucleated cells elicited in rats by particulate bone, polyethylene, or polymethylmethacrylate

Osteoclasts, the multinucleated resorbing cells of bone, are identified by their characteristic morphology, unique cell membrane specializations, and more recently by the presence of cell surface antigens recognized by monoclonal antibodies. They are derived from mononuclear precursor cells of hematogenous origin. The precise relationship between osteoclasts and other types of tissue giant cells is unknown. This study was designed to examine factors involved in the recruitment and differentiation of multinucleated cells and to investigate the relationship between so-called foreign body giant cells and bone-resorbing osteoclasts. Particles of various materials were implanted into subcutaneous pockets in rats. Histological, histochemical, and electron microscopic evaluations were made of specimens harvested 12 days after implantation. Large, foamy multinucleated cells were evident around particles of devitalized bone, polyethylene, and polymethylmethacrylate. Bone particles showed scalloped surfaces and were partially resorbed. Those cells adjacent to the bone particles stained positive for tartrate-resistant acid phosphatase, in contrast to the multinucleated cells adjacent to the other materials. All the cell types had extensive rough endoplasmic reticulum, abundant mitochondria, cytoplasmic vacuoles and dense bodies, giant centrospheres, and areas of fusion of plasma membranes. Cells in lacunae on the surface of the bone particles showed a clear zone of attachment to the bone substrate and ruffled borders, a feature characteristic of in osso osteoclasts. Although the giant cells occasionally displayed an extensive clear zone of attachment to the polyethylene and polymethylmethacrylate particles, no ruffled borders were detected. The results of these studies show that the multinucleated cells elicited in response to different materials, although sharing many common features, do demonstrate certain features that are substrate specific.(ABSTRACT TRUNCATED AT 250 WORDS)

Giant cell formation by peripheral human monocytes

Peripheral monocytes from patients with breast carcinoma were incubated in vitro using an under agarose technique. The monocytes were incubated at 37 degrees C in a 5% CO2 atmosphere using a mixture of 0.75% agarose gel in Eagle's medium supplemented with 10% group AB pooled human serum and 50 micrograms/ml zymosan-activated serum. Significant giant cell formation occurred after 6 days incubation and was most marked after 9 days. The optimum pH for giant cell formation was between 7.0 and 7.4. The age of the subject (range 20-50 years), type of coagulant, delay in monocyte separation, storage of the monocyte preparation for up to 24 h at 4 degrees C, and freezing for up to 3 months, had no effect on giant cell formation. No giant cell formation was observed in control subjects.

Role of alveolar macrophage- and lung T cell-derived mediators in pulmonary sarcoidosis

The process of granuloma formation in the lung is mediated by an intimate interaction between macrophages and T cells, and this interaction provides the appropriate environment for granuloma formation and the development of fibrosis. Much of this process of granuloma formation and fibrosis appears to be triggered by the release of immune mediators by alveolar macrophages and lung T cells.

Quantitative characterization of cells at the interface of long-term implants of selected polymers

Comprehensive understanding of the relationship between biologic response and biomaterial characteristic requires quantitative evaluation of the cells at the interface of the material and descriptions of ultrastructural features of these cells. The purpose of this study was to qualitatively and quantitatively characterize the long term in vivo tissue and cellular response to two polymeric materials presently employed in the fabrication of surgical implants. Ultrahigh molecular weight polyethylene (PE) and polysulfone (PSF) particles were implanted subcutaneously into rats for 100-118 weeks. Specimens were embedded in paraffin and ERL embedding medium in preparation for light and transmission electron microscopy. Percentage of the particle surface covered by various cell types was determined using a computer interactive image analysis system. PE and PSF particles were sequestered within a subcutaneous fibrous capsule. Cell types present included macrophages, fibroblasts and giant cells characteristic of a foreign body granuloma. Statistical comparison of the percent particle surface covered by each cell type revealed no significant difference between PSF and PE. However, surface texture appeared to influence the tissue response. TEM confirmed the identity of the cells at the interface and consistently revealed a layer of amorphous extracellular substance including cell debris on the material surface. Results evidence the tissue compatibility of PE and PSF and indicate no significant difference in the tissue response to these polymers.

Histological parameters and pitfalls in the interpretation of bladder biopsies in bacillus Calmette-Guerin treatment of superficial bladder cancer

We report the morphological effects of intravesical bacillus Calmette-Guerin therapy on early post-treatment biopsies of the bladder in 39 patients with superficial transitional cell carcinoma (stage Ta, T1 or Tis) of the bladder. Although submucosal granulomatous inflammation in bladder biopsies of patients receiving intravesical bacillus Calmette-Guerin treatment has been described previously, a complete morphological description of the early effects of bacillus Calmette-Guerin on all bladder layers and the prostatic urethra has not been reported. In the majority of cases the superficial epithelium was eroded and the edematous submucosa contained noncaseating granulomas with a surrounding lymphoplasmocytic and eosinophilic infiltrate. Langhans' giant cells occasionally were found, and acid-fast bacilli were demonstrated only rarely by special stains in the 6-week post-treatment biopsy. In some cases the prostatic urethra and muscle bundles contained noncaseating granulomas. Features distinguishing epithelial atypia resulting from bacillus Calmette-Guerin treatment and superficial cancer include the presence of epithelial maturation, preserved nuclear/cytoplasmic ratio, smooth nuclear contours and lack of nuclear pleomorphism, nucleoli or cytomegaly.

Electrophysiology of phagocytic membranes. Role of divalent cations in membrane hyperpolarizations of macrophage polykaryons

The electrophysiological properties of the membrane of mouse peritoneal macrophage polykaryons are studied. Slow hyperpolarizations can be elicited by iontophoretic injections of either Ca2+ or Sr2+ into the cytoplasm. The effect of both cations is identical, since: it is invariably triggered by the cation injection, the amplitude is dependent on the K+ gradient, quinine blocks reversibly the response to both cation injections. Mg2+, Ba2+ and Mn2+ did not elicit responses when injected into the cytoplasm. Ca2+ induced slow hyperpolarizations were reversibly blocked by the addition of Ba2+ to the external saline, but were not affected by the presence of external tetraethylammonium chloride. Cells maintained in saline containing high concentrations of Ca2+, Sr2+ or Mn2+ exhibited sustained hyperpolarizations. Quinine blocked the hyperpolarization induced by high Ca2+ or Sr2+, but was ineffective for the case of Mn2+. Cells hyperpolarized by external Mn2+ frequently exhibited nonlinear, voltage-current characteristics. Similar patterns could also be observed in a small fraction (less than 10%) of the cells in control conditions. Current-induced shifts between two stable membrane potentials were seen either in high Ca2+ or normal medium. The great variability of the responses described for this phagocytic membrane is discussed. The evidence supports the assumption that Ca2+ and Sr2+ can induce transient or persistent hyperpolarized states by activating a potassium permeability. External Mn2+ may act in part by reducing impalement-related current leakage from the phagocytic membrane.

Evidence that multinucleate giant cells are examples of mononuclear phagocytic differentiation

Murine multinucleate giant cells and mononuclear phagocytes were examined with various quantitative cytochemical and autoradiographic techniques. No evidence was found that multinucleate giant cells were metabolically effete, in fact they compared favourably with mononuclear phagocytes. In addition, rat multinucleate giant cells consistently expressed surface Ia antigens and to a lesser degree fibronectin. It is suggested that multinucleate giant cells are a differentiated derivative of the mononuclear phagocytic system.