Macrophage spreading: inhibition in delayed hypersensitivity

Aspirin 15cH has Different Effects on Morphology and Function of Lipopolysaccharide-Challenged RAW 264.7 Macrophages In Vitro Compared to a Pharmacological Dose of Aspirin

INTRODUCTION

 Aspirin is one of the most commonly used drugs worldwide. It is known to present antipyretic, anti-inflammatory and anti-thrombotic actions, making it extremely useful in a wide range of clinical contexts. Interestingly, homeopathically prepared Aspirin 15cH has been found to have a pro-thrombotic effect in rats, raising the hypothesis that Aspirin 15cH could also modulate the activity of inflammatory cells in different pathological processes.

OBJECTIVE

 Our objective was to assess what effect Aspirin 15cH has on RAW 264.7 macrophages in vitro.

METHODS

 The effects of Aspirin 15cH on biochemical and morphological activities of lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages were evaluated. These effects were compared with unchallenged macrophages (negative control), untreated LPS-stimulated macrophages, macrophages treated with succussed water (vehicle control), or aspirin 200 µg/mL (pharmacological inhibitor of LPS activity). Cell morphology (adhered cell area and cytoskeleton arrangements), cell viability, toll-like receptor-4 (TLR-4) expression, and the production of nitric oxide, cytokines and intracellular reactive oxygen species were assessed.

RESULTS

 Aspirin 15cH reduced the number of cells expressing TLR-4 on the surface (p = 0.03) and induced a "columnar" morphology of macrophage pseudopods, indicating changes in cytoskeleton arrangement. When cells were treated with both Aspirin 15cH and LPS, cell morphology became heterogeneous, suggesting that sub-populations of cells had differing sensitivities to LPS or Aspirin 15cH. Exposure of the cells to LPS alone, succussed water or aspirin 200 µg/mL produced effects consistent with the literature.

CONCLUSION

 Aspirin 15cH, aspirin 200 µg/mL, LPS and succussed water appear to act as independent stimuli able to induce different patterns of macrophage response. Aspirin 15cH induced changes suggestive of M2 polarization of the macrophages (i.e., toward a wound healing or tissue repair, rather than inflammatory, phenotype). These preliminary findings need to be confirmed in further specific studies.

Migration inhibition produced by sodium periodate oxidation of the macrophage membrane, and reversal by sodium borohydride

Guinea pig peritoneal exudate cells were harvested 3 to 4 days after the intraperitoneal injection of Marcol oil. The washed cells were exposed to various concentrations of sodium periodate in phosphate-buffered saline (PBS) at pH 7.4 for 10 min at +4 degrees C. The cells were then used in the in vitro migration assay, and migration was consistently inhibited at concentrations from 10(-3) to 10(-5) M. The viability of the macrophages was not affected by this treatment. Sodium borohydride (10(-3) to 10(-5) M) in PBS for 10 min at pH 7.4 reversed the periodate effect. Experiments with purified macrophages showed that sodium periodate has a direct effect on macrophage function rather than an indirect effect via the potentiation of migration inhibition factor. In support of this, the in vitro spreading of macrophages on glass substrate for 1 h has been shown to be inhibited. This spreading inhibition can also be reversed by treatment with sodium borohydride. These results provide a new approach to understanding the biological significance and role of macrophage migration inhibition.

Influence of circadian light-dark alternations on macrophages and lymphocytes of CBA mouse

The influence of circadian 12 h light-12 h dark alternations on CBA mouse macrophages and lymphocytes was determined using tests for macrophage spreading and ingestion ability or flow cytometry immunophenotyping of blood, lymph node, and spleen lymphocytes. The animals were tested every 4 h around the clock. Collected macrophages were incubated in vitro for 3 or 18 h. Monoclonal antibodies permitted detection of T-lymphocytes, suppressor-cytotoxic T-lymphocytes, helper-inducer T-lymphocytes, or B-lymphocytes. Two types of analyses were performed: First, the difference between the same intervals of the 12 h light or dark period was determined. The macrophage ingestion was significantly lower at the beginning and higher at the end of the dark period. We have also found a significant increase in blood T-lymphocytes of helper-inducer T-lymphocyte percentages and of the T helper-inducer: T suppressor-cytotoxic ratio during the dark period. Second, the ultradian variation during the 12 h light or dark period was determined. The variability was significant both for macrophage spreading and ingestion. Multiple significant variations of lymph node, spleen, or blood lymphocyte percentages were also observed. All of these data indicate that daily alteration of the lighting regimen significantly influences mouse peritoneal macrophage functions and various lymphocyte subsets.

Immunogenetic and immunologic studies of differentiated thyroid cancer

The authors have studied in detail human leukocyte antigen (HLA) association in 87 Hungarian patients with thyroid epithelial carcinoma. The authors also examined in a small group of patients, five parameters of cell-mediated immunity and related them to HLA as well as to lymphocytic infiltration of the tumor/normal tissue interface. HLA-DR1 was significantly associated with thyroid carcinoma; the strongest association was in patients with follicular histologic features and DR1 homozygotes were not at greater risk for thyroid cancer. The HLA-DR3 was nonsignificantly increased in patients with papillary or mixed histologic features. The HLA-DR1, 3 heterozygotes were highly associated with follicular carcinoma, carried no risk for papillary carcinoma, and an intermediate risk for tumors with mixed histologic features. Because of the small proportion of DR1, 3 heterozygotes in the follicular and mixed histologic group, its predictive value at the population level was low. Better predictive potential was shown for the phenotype DR1 and/or DR3. Neither metastatic disease nor age at diagnosis (less than 45 years) could be related to HLA phenotypes. Patients in all histologic variants showed some measure of cell-mediated immunity compared to controls. Patients with papillary carcinoma showed an overall better response than those with tumors with follicular or mixed histology. The HLA-DR could not be related to cell-mediated immune response. Patients with papillary carcinoma with a good cell-mediated immune response occurred with much lower infiltration of the tumor boundary with lymphocyte whereas the follicular carcinoma less cell-mediated immunity was associated with dense lymphocytic infiltration, suggesting the biological relevance of lymphocytic infiltration may be different for the two histologic variants.

Macrophage procoagulant-inducing activity of influenza-specific effector T cells

Three different types of immune mouse T cells raised against influenza virus were tested for their ability to induce the formation of macrophage procoagulant activity (MPCA) by a macrophage cell line PU5-1.8. They were primary spleen cells, taken 6 days after iv injection of virus, spleen cells from sensitized mice challenged with virus and cultured in vitro for 5 days (secondary cultured cells), and cloned T cells. With the last two preparations, some samples were K,D region restricted, Lyt 2+, and had cytotoxic activity; other samples were I region restricted, Lyt 2-, and were not cytotoxic. Samples of a concanavalin A-activated T-cell supernatant which regularly induced MPCA with PU5-1.8 cells were included as controls in all assays. A few batches of T-cell preparations failed to induce MPCA production, however, most batches were active. Two sources of variation were detected: first, the number of cells (5- to 150-fold) needed to induce a certain level of MPCA, as measured by the decrease in clotting time; and second, the value of the gradient of the cell dose response. Both K,D- and I-region-restricted cells, either as cloned or secondary cultured cells, could induce MPCA but with the latter preparation, I-region-restricted cells were the better inducers by about eightfold. T cells tested in this way were also injected into mouse hind footpads and their ability to mediate delayed-type hypersensitivity (DTH) reactions was measured. A positive but not proportional correlation between the abilities to induce MPCA and mediate DTH activity for primary spleen cells was found, but this was not generally observed with cultured or cloned T cells.

Interaction of Lotus-tetragonolobus Lectin (LTL) and an MIF-like factor with guinea-pig macrophages. I. Effects on macrophage migration inhibition and receptor-binding studies

Purified Lotus-tetragonolobus lectin (LTL) was studied for its interaction with guinea-pig peritoneal macrophages in the migration-inhibition and spreading-inhibition assay. LTL was found capable of inhibiting macrophage migration in a dose-response relationship similar to that of an MIF-life factor present in rat Zajdela-hepatoma ascites, whereas macrophage spreading was less affected. Mitogenic activity of the fucolectin could be excluded. Both the LTL and MIF-like factor seem to come into action by means of alpha-L-fucopyranosyl residues-containing macrophage surface receptors. Both substances act synergistically in inhibiting migration of macrophages. Since binding studies with 125I-LTL demonstrated competition with the MIF-like factor, it is suggested that the latter and LTL share a common surface receptor, and that optimal occupation densities are required for the realization of the inhibitory effect. Possibly, LTL acts in a monomeric form in the migration inhibition assay.

Detection of cellular immunity to tumor-associated antigen(s) in mice by the macrophage spreading inhibition test

Soluble preparations of antigens from a methylcholanthrene-induced fibrosarcoma of C57BI mice were prepared by homogenization of tumor tissue and high-speed centrifugation of the homogenate. These preparations were able to sensitize syngeneic mice to tumor-associated antigens (TAA) of the fibrosarcoma, and to provoke a delayed hypersensitivity reaction when injected into the footpad of sensitized mice. Furthermore, the same soluble preparations could inhibit in vitro the spreading of peritoneal macrophages from mice sensitized to TAA. A similar inhibition of macrophage spreading was obtained when peritoneal cells from C57BI mice, bearing transplants of the fibrosarcoma, were incubated with the preparations. We conclude that the macrophage spreading inhibition test, like other in vitro assays, can detect cell-mediated immunity to tumor-associated antigens.

Cellular immunity in vitro: migration inhibition and phagocytosis

The activity of peritoneal exudate cells from candidin-sensitive and normal guinea pigs with and without antigen was studied in vitro with the aid of time-lapse, phase-contrast cinemicrography. Macrophages from normal animals migrate well on an agar medium and readily phagocytose Merthiolate-killed Candida albicans cells. A reduction in the migration of peritoneal macrophages from guinea pigs sensitized to C. albicans during the first 24 hr after exposure to antigen was accompanied by a decrease in phagocytosis of C. albicans cells. The macrophages were viable but comparatively immotile. Since the sensitized macrophages came from resistant donors, it is possible that the initial stage of cellular immunity to C. albicans is associated with a reduced activity of the phagocytic macrophages, apparently to limit spread of the pathogen from the infected area.

Alterations of macrophage functions by mediators from lymphocytes

Sensitized lymphocytes were incubated in vitro with the specific antigen Supernatants from these cultures were chromatographed on Sephadex G-100 columns. Supernatant fractions containing MIF, chemotactic factor, and lymphotoxin, but free of antigen and antibody, were incubated with normal peritoneal exudate macrophages. Macrophage adherence, phagocytosis, spreading, motility, and direct hexose monophosphate oxidation were enhanced, while protein synthesis was unaffected. Thus, antigen-stimulated lymphocytes secrete a factor or factors which enhance certain macrophage functions. Implications for models of cellular immunity and cellular hypersensitivity are discussed.