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When MRL/1 mouse spleen cell culture supernatants were incubated with normal mouse spleen cells, a two-50-fold increase in anti-dsDNA activity was noted. A smaller increase in anti-ssDNA and no change in anti-TNP antibody activity were observed. This 'hidden' antibody in the MRL/1 supernatants could not be revealed by DNAase digestion and could not be absorbed by a DNA cellulose column. Hidden antibody was removed from supernatants by sepharose-anti-Ig. After DNAase digestion of the MRL/1 supernatants, hidden anti-dsDNA could not be revealed by incubation with spleen cells. All the hidden activity was excluded by gel filtration on Sephacryl S-300 (mol. wt > 300,000) but was banded in the low density protein area of caesium chloride equilibrium density gradients. It was also noted that MRL/1 mouse sera had hidden anti-dsDNA antibodies. Hidden antibodies were present in both the IgG and IgM classes. The revealed antibodies demonstrated impaired ability to bind Fe specific anti-Ig reagents suggesting that they were partially degraded during the incubation with mouse spleen cells. The hidden anti-dsDNA thus appears to represent a DNA-anti-dsDNA complex, perhaps of very high affinity. It may explain why anti-dsDNA but not anti-ssDNA antibodies are of pathological importance in SLE. [ABSTRACT FROM AUTHOR]

The relationship between renal interstitial mononuclear cell infiltration and renal tubule cell (TC) proliferation has been examined in (NZB × NZW)F1 hybrid (B/W) and control mice. TC proliferation was measured by tritiated thymidine ([³H]TdR) injection, autoradiographic examination of kidney sections and enumeration of labelled tubule cells. In B/W mice interstitial infiltration began at 5 months and reached a peak at 9 months. Proliferation of TC began at 7 months and also reached a peak at 9 months. Control mice consisting of NZB, CBA/J and C57B1/6J mice showed no increase with age. When the percentages of labelled TC in areas adjacent to interstitial infiltrates and distant from them were compared, the TC adjacent to infiltrates showed an approximately four-fold greater amount of labelling. Ultrathin light and electron microscopic sections demonstrated TC injury in areas in close proximity to infiltrates. These studies suggest that mononuclear cells in the interstitial infiltrate may he injurious to TC, leading to a sequence of injury and subsequent regeneration of these cells. In diseases in which interstitial nephritis is present, such as Sjögren's syndrome, the interstitial infiltrate may contribute to the observed TC dysfunction. [ABSTRACT FROM AUTHOR]

The effects of cyclophosphamide on antinuclear antibody levels, immune complex deposition in renal glomeruli, glomerular cell proliferation and glomerulosclerosis in the (NZB × NZW)F1 hybrid mouse have been investigated in order to better understand the mechanism of action of this drug on nephritis. Five groups of mice were injected daily with this agent (15 mg/kg) by the i.p. route over a 2-month period. Treatment periods began at 1, 3, 5, 7 and 9 months. Each group was killed at the end of the treatment period. During the last week [³H]Tdr (1 μCi/g) was injected daily i.p. Immune complex deposition was measured by quantification of glomerular immuno-fluorescent staining in both capillary loops and mesangium. Glomerular cell proliferation was quantified by measurement of the number of glomerular cells which incorporated [³H]Tdr during in vivo labelling. The number of [³H]Tdr-labelled cells in each of 100 glomeruli was counted using kidney autoradiographs of whole kidney slices. This technique provided a very reproducible and quantitative index of glomerular cell proliferation. Glomerulosclerosis was measured by determining percentage of PAS-positive material in each of 100 counted glomeruli. Immune complex deposition in the kidney preceded the glomerular cell proliferation. The proliferation reached a peak at 9 months of age. Glomerulosclerosis gradually increased with age until the animal's death. Cyclophosphamide significantly decreased antinuclear antibody levels, glomerular cell proliferation, and immunoglobulin staining in the glomeruli. Progression of glomerulosclerosis was significantly arrested. The present findings demonstrate a very significant effect of cyclophosphamide on three important pathological changes which occur in the nephritis of the (NZB × NZW)F1 hybrid mouse and provide information about possible mechanisms underlying these changes. [ABSTRACT FROM AUTHOR]

Since all dental restorative materials are foreign substances, their potential for producing adverse health effects is determined by their relative toxicity and bioavailability, as well as by host susceptibility. Adverse health effects to dental restoratives may be local in the oral cavity or systemic, depending on the ability of released components to enter the body and, if so, on their rate of absorption. The medical scientific community is now in general agreement that patients with dental amalgam fillings are chronically exposed to mercury, that the average daily absorption of mercury from dental amalgam is from 3 to 17 micrograms per day, and that the amalgam mercury absorption averages 1.25-6.5 times the average mercury absorption from dietary sources (World Health Organization, 1991). The health significance of this chronic mercury exposure is now being investigated by several medical research groups. [ABSTRACT FROM AUTHOR]

The possible rule of phagocytosis of circulating immune complexes by neutrophils in the production of the neutropenia of Felty's syndrome has been investigated. Normal neutrophils phitgocytosed massive inclusions from the sera from twelve of fifteen patients with Felty's syndrome when incubated with these sera. Such inclusions were phagocytosed from only three of fifteen patients with seropositive RA who did not have Felty's syndrome. Normal neutrophils were more effective than patient neutrophils with regard to phagocytosis of inclusions from the patients' serum suggesting a defect in phagocytic function of Felty's neutrophils. The titre of granulocyte-reactive antinuclear antibodies did not appear to be related to the degree of neutropenia. The data suggest that phagocytosis of circulating immune complexes by neutrophils may interfere with the function of these cells in combating infection and also render them susceptible to removal from the circulation thus leading to the development of neutropenia. [ABSTRACT FROM AUTHOR]

Recent evidence indicates that interleukin 1 (IL-I) from different sources has varying molecular weights, amino acid and gene sequences and biological properties. In previous experiments, it has been shown that monocyte derived IL-l was chemotactic for lymphocytes and stimulated their binding to endothelial cells (EC). These phenomena are important in the emigration of lymphocytes in inflammatory states. In the present investigation, EC were stimulated with LPS and from the supernatants the IL-l activity was isolated. After AcA 54 gel filtration, the active 17 kD fraction was further purified by chromatofocusing, yielding active fractions with pI of 7.0 and 5.0. All of these fractions showed T lymphocyte chemotactic activity, stimulated the binding of T cells to EC and the proliferation of fibroblasts. It is concluded, therefore, that EC-derived IL-1 has similar biological activity to that of monocyte-derived lL-1 and that it can exert a true autocrine effect at the blood-tissue endothelial interface. [ABSTRACT FROM AUTHOR]

Binding of lymphocytes to human umbilical vein endothelial cells (EC) was quantitated by measuring (a) adhesion of 51Cr labelled lymphocytes to endothelial cell monolayers and (b) rosette formation between lymphocytes and EC in suspension. Mitogen stimulated human peripheral blood mononuclear cell culture supernatants and mixed lymphocyte reaction supernatants enhanced the binding of T lymphocytes to EC monolayers or suspensions preincubated with such supernatants. The active component of these supernatants appeared to be gamma interferon (IFN-γ) since culture supernatants lost activity filter heating at 56°C for 60 min, exposure to pH 2.0 or treatment with anti-IFN-γ. In addition, purified IFN-γ increased the binding of T lymphocytes to EC (T-EC). This occurred in a concentration dependent manner when IFN-γ was preincubated with EC but not with lymphocytes. While the optimum concentration of IFN-γ was 250 u/ml, a significant enhancement was seen with as little as 10 u/ml. These findings suggest that IFN-γ may play a part in the emigration of lymphocytes to perivascular chronic inflammatory sites by augmenting the adhesion of lymphocytes to the endothelium of small blood vessels. [ABSTRACT FROM AUTHOR]

The presence of fibronectin (Fn) in rheumatoid pannus was investigated by an immunoelectron microscopic method using horseradish peroxidase-conjugated antibody to stain Fn. Large amounts of Fn were demonstrated in the interstitial collagenous tissue of invasive rheumatoid pannus. Fn was also observed on the surface of both fibroblast-like and macrophage-like pannus cells, suggesting that it was secreted by these cells and that the secreted Fn might facilitate the spreading of the pannus cells over the cartilage matrix. However, decreased amounts of Fn were observed in areas of contact between pannus cells and the cartilage matrix. The reduction in the amount of Fn demonstrable at the cartilage-pannus junction may be a consequence either of proteolysis of Fn by enzymes secreted at the junction, inhibition of Fn synthesis in cells in contact with cartilage matrix, or transfer of Fn from the pannus cell surface to collagen of the cartilage matrix. [ABSTRACT FROM AUTHOR]

When single random serums from sixty patients with systemic lupus erythematosus (SLE) were examined for cytotoxicity against allogeneic lymphocytes, thirty-six or 60% were found to be cytotoxic. In controls, consisting of eighteen blood bank donors, forty-live clinic patients matched to the SLE group, and 366 multiparous women, cytotoxicity was found in 0, 4 and 12%, respectively. When 151 serums from twenty SLE patients were tested against their own lymphocytes, twenty-four serums from twelve patients gave autologous reactions. Cytotoxicity of SLE serums for both allogeneic and autologous lymphocytes was complement dependent and could be specifically absorbed with reactive lymphoeytes, suggesting that the factor responsible for cytotoxicity was an antibody. Since activity was present at 37°C, cytotoxicity may be assumed to be manifest in vivo. These antibodies may play a role in the leukopenia of SLE and may also be responsible for other manifestations of multisystem disease. [ABSTRACT FROM AUTHOR]

The effect of phytohaemagglutinin (PHA) on the immune response of mice and rats has been investigated. A marked depression of anti-sheep erythrocyte agglutinin titres was found in both species following primary immunization. The decrease in titre was due to a depression of 2-mercaptoethanol resistant antibodies. The treated rats also developed antibodies against the haemagglutinating component of PHA. PHA produced no depression of the delayed hypersensitivity response to tuberculin; nor did it suppress adjuvant arthritis in the rat. Histological examination of the lymphoid organs of PHA treated mice revealed reactive hyperplasia. Similar histological challenges were seen in mice injected at the same time with a strong antigen such as horse ferritin. The depressive effect of PHA on IgG antibody formation and the absence of an effect on IgM antibody formation, delayed hypersensitivity, and adjuvant arthritis arc discussed. [ABSTRACT FROM AUTHOR]

Foreign proteins have been compared with their corresponding isologous and autologous proteins with respect to their capacity to induce inflammatory reactions at the site of injection in the skin. In contrast to the foreign proteins, which consistently produced mild reactions which were morphologically similar to the delayed hypersensitivity reaction, autologous and isologous proteins failed to induce local accumulations of inflammatory cells. The capacity of cells at the inflammatory site to phagocytoze heterologous and isologous ferritin was investigated in the electron microscope, and no qualitative differences were noted. The results are interpreted as evidence for the existence of a local mechanism capable of differentiating between foreign and autologous protein. The possible significance and role of such a mechanism is discussed. [ABSTRACT FROM AUTHOR]

The tuberculin reaction was examined in the electron microscope using as antigen PPD conjugated to ferritin. The ferritin marker was rapidly localized within macrophages prior to the time of significant lymphocyte accumulation. Evidence of degenerative changes in macrophages was seen. Uptake of marker by lymphocytes was not noted. Appropriate control experiments indicated that the uptake of antigen by macrophages and subsequent macrophage degeneration were not dependent on previous sensitization. The accumulation of lymphocytes without apparent contact with unaltered antigen was interpreted as evidence that lymphocyte accumulation was a consequence of the prior interaction between antigen and macrophages. [ABSTRACT FROM AUTHOR]

Cultures of synovial tissue from rabbits with an antigen-induced arthritis were tested for production of macrophage migration inhibitory factor to investigate the possible role of cellular immunity in this experimental model. Culture supernatants of ten specimens of normal rabbit synovium and six specimens from joints injected with saline did not inhibit macrophage migration; and in thirteen experiments with synovium from an arthritis produced by injection of urate crystals only one showed significant inhibitory activity on macrophages. In contrast nineteen of twenty-five antigen challenged joints produced migration inhibitory factor detectable in the culture supernatants. Inhibition ranged from 20 to 87 percent with a mean of 31. 7±4.3 per cent. The migration inhibitory factor in these fluids was non-dialysable and was eluted with an albumin marker from Sephadex G-200. The finding that a macrophage migration inhibitory agent is produced in the course of antigen-induced synovitis is consistent with the postulated role of cellular immunity in the synovial lesion. [ABSTRACT FROM AUTHOR]

The immunosuppressive and anti-inflammatory Properties of rabbit antirat macrophage (AMG) and rabbit antirat thymocyte globulin (ALG) have been compared. Iv vitro experiments showed that both AMG and ALG contained antibodies directed against rat thymocytes and macrophages. When AMG was absorbed with large numbers of thymocytes, the final product was found to lack agglutinating and Cytotoxic antibodies against such cells, However, AMG was cytotoxic to rat peritoneal macrophages at a dilution of 1/512 while the ALG cytotoxic titre was 1/64. It was also shown that AMG was able to suppress phagocytosis by peritoneal mononuclear cells while ALG was ineffective. The immunosuppressive activity of AMG and ALG when given at the time of induction of the immune response was studied in vivo. Rats were pretreated with the antisera prior to induction of Freund's adjuvant arthritis and immunization with sheep erythrocytes. Administration of ALG prior to induction of adjuvant arthritis resulted in complete inhibition of the disease while AMG treated rats developed, arthritis. ALG treated rats produced almost no haemagglutinating antibody to sheep erythrocytes used as antigen while the AMG treated group developed titres not significantly different from the control group. When the same animals were rechallenged with sheep erythrocytes 5 weeks later the response of the AMG treated group was similar to that of controls, while the ALG treated animals developed a primary antibody responses. When the antisera were given to animals coinciding with the development of generalized arthritis in order to study their anti-inflammatory activity, AMG treated rats showed a small decrease in the severity of arthritis, ALG was much more effective in reducing the inflammatory signs of the disease and its suppressive effects lasted for 2 weeks after the last injection. The anti-inflammatory properties of ALO were also evident in the marked inhibition of the granuloma in the adjuvant-injected paw Which paralleled the effects of treatment on the poly- arthritis. Similarly, ALG treatment produced a severe depression of the delayed hypersensitivity response to tuberculin while AMG was ineffective. The above results indicate that ALG is a strong anti-inflammatory and immunosuppressive agent while AMG has no immunosuppressive properties and is only a mild anti-inflammatory agent. [ABSTRACT FROM AUTHOR]

The effects of 6-mercaptopurine (7.5 mg/kg) and cyclophosphamide (15 mg/kg and 30 mg/kg) on various aspects of the immune response have been compared in New Zealand Black (NZB) mice. injections were given daily lot 5-8 weeks. Serologic and morphologic studies during and after treatment revealed the Following: (1) 6-MP decreased the levels of circulating polymorphonuclear leucocytes, monocytes, and large lymphocytes; small and medium lymphocyte counts remained unchanged. in contrast, cyclophosphamide decreased mainly the small and medium lymphocytes, leaving the other cell types unchanged, (2) In older animals, 6-MP produced a marked fall in haematocrit, while cyclophosphamide did not do so. (3) Cyclophosphamide delayed the onset of Coombs positivity and decreased the Coombs antibody titre. it also decreased immunofluorescent staining of γ-globulin deposits in the kidney. 6-MP had no such effects. The results suggest that 6-MP exerted an anti-proliferative action on the bone marrow, as shown by a decrease of short-lived cells in the blood. Cyclophosphamide, on the other baud. appeared to have mainly a cytotoxic effect on circulating cells, resulting in depletion of the long-lived small lymphocytes of the blood and leading to inhibition of autoantibody formation and immune complex deposition in the kidney. Cyclophosphamide would therefore, appear to be the preferable drug where suppression of ongoing cellular and humoral immune reactions is desirable. [ABSTRACT FROM AUTHOR]

The article focuses on immunoglobulin synthesis in vitro by human thymus. Immunoglobulin synthesis measured in incubated thymus tissue by the incorporation of Carbon 14 labeled amino acids has been studied in four thymus glands from patients with myasthenia gravis and in eight normal thymus glands from patients undergoing open heart surgery. Thymus tissues from patients with myasthenia gravis incorporated an average of twice as much radioactivity into soluble protein on a wet weight basis as normal thymus tissues.

The article cites a study conducted by the author, which tested the immunofluorescent demonstration of an immunoglobulin complex in synovial lining cells of rheumatoid synovial membrane. In the study, synovial tissues obtained at arthrotomy or by needle biopsy were digested with trypsin, and suspensions of synovial cells were isolated. Immunofluorescent staining of these cells has shown the simultaneous presence of immunoglobulin G and the beta component of complement in the cytoplasm of most of the phagocytic lining cells of fifteen of seventeen synovia obtained from both seropositive and seronegative patients with rheumatoid arthritis. This staining pattern was not found in synovial cells obtained from patients with other inflammatory or non-inflammatory arthritides.