Characterization of mouse lymphocyte-derived chemotactic factor

Inhibition of the accumulation of macrophages and the generation of macrophage chemotactic activity by dexamethasone in concanavalin A-induced peritonitis of mice

A delayed-type inflammatory response was evoked in mice using concanavalin A (Con A) as a stimulus, and the effect of various anti-inflammatory agents on the inflammation was examined. The intraperitoneal injection of Con A in the mouse resulted in the marked accumulation of leukocytes, especially macrophages, in the peritoneal cavity between 16 and 48 hr after the injection. Prior to the accumulation of macrophages, the chemotactic activity for macrophages appeared in the peritoneal fluid, and was associated with protein(s) in the molecular weight range from 10,000 to 100,000 daltons. When the effect of various agents on Con A-induced peritonitis was examined, neither anticomplementary agents (FUT-175 and K-76 COONa), bromophenacyl bromide, nordihydroguaiaretic acid nor indomethacin affected the generation of chemotactic activity and the accumulation of macrophages, suggesting that C5a, prostaglandins and leukotriene B4 are hardly involved in the Con A-induced macrophage accumulation. On the other hand, dexamethasone suppressed both the generation of chemotactic activity and the accumulation of macrophages. Taking into consideration the observation that the synthesis of macrophage chemotactic factors by mitogen-stimulated lymphocytes is inhibited by glucocorticoids, these results suggest that the macrophage chemotactic lymphokines might be involved in the accumulation of macrophages in Con A-induced peritonitis.

A significant role of the macrophage accumulation induced by MCF in the protection of mice against Listeria monocytogenes in vivo

Analysis was done on macrophage chemotactic factor (MCF) produced in the culture supernatant of spleen cells from mice immunized with Listeria monocytogenes. MCF was produced by Thy-1+, Lyt-1+ lymphocytes. MCF activity was resistant against pH 2 treatment and heating at 56 degrees C for 30 min, but was abolished by digestion with trypsin. G-100 gel filtration chromatography revealed that the approximate molecular weight of MCF was 15,000. MCF-rich fraction obtained by gel filtration chromatography showed neither MAF activity nor interferon activity. MCF activity in MCF-rich fraction was not affected by treatment with anti-rIFN-gamma antibody. An injection of MCF-rich fraction into the peritoneal cavity of mice induced a significant degree of accumulation of polymorphonuclear leukocytes (PMN) in a very short time after injection and macrophages thereafter. Resistance against listerial infection was augmented at the site where macrophage accumulation was provoked by the injection with MCF-rich fraction. It was shown that MCF plays an important role by itself in the protection against listerial infection by the accelerated accumulation of macrophages.

Absence of lymphokine-enhanced macrophage migration in vitro in the Australian brush-tailed opossum, Trichosurus vulpecula

The supernatants from cultures of either opossum or guinea pig splenic lymphocytes, stimulated with phytohaemagglutinin, significantly enhanced the in vitro migration of guinea pig peritoneal macrophages (P greater than 0.001) but not that of opossum peritoneal macrophages. Failure of opossum macrophages to respond to a putative macrophage chemotactic factor might account for the observed paucity of immune granulomas in these animals and help explain the species' susceptibility to tuberculosis.

Effect of histamine on delayed-type hypersensitivity in mice

The effect of histamine on delayed-type hypersensitivity provoked in the abdominal cavity of mice was studied. When histamine (0.1-10 mg/kg) was injected twice a day for 2 consecutive days after antigen challenge, cell accumulation in the inflamed site and the production of lymphokine was significantly suppressed. Similar suppressive effects were observed after injection with an H2-agonist, dimaprit, but not in the case of an H1-agonist, 2-methylhistamine. The effect of histamine on cell accumulation in an implanted sponge was blocked by the H2-antagonists, cimetidine and ranitidine, but only slightly by the H1-antagonists, pyrilamine and diphenhydramine. In adrenalectomized mice, the suppressive effect of histamine was slightly weaker than in normal mice, but the inhibitory effect of histamine was almost completely blocked by H2-antagonists in both cases. The suppressive effect of histamine on the production of lymphokine (macrophage chemotactic factor) was also blocked by cimetidine. Using gel chromatography, the chemotactic activity fraction was eluted as molecules having a molecular weight of 30,000-70,000. These results suggest that the histamine-induced suppression of the delayed-type hypersensitivity reaction in mice is affected mainly by the production of lymphokine(s) via an H2-receptor-bearing lymphocyte.

Macrophage-chemotactic factor-producing T cell hybridomas reactive to phosphorylcholine in I-E-restricted manner

Macrophage-chemotactic factor (MChF)-producing T cell hybridomas were established. These hybridomas produced MChF upon the specific antigenic stimulation with phosphorylcholine (PC)-conjugated protein in the presence of I-Ed-positive antigen-presenting cells. The hybridomas also secreted MChF after co-culture with concanavalin A in the absence of antigen-presenting cells. The MChF-secreting hybridomas were positive for Kd, Dd, Lyt-1.2 but negative for I-Ad, Lyt-2.2. The molecular weight of MChF produced by the hybridomas was 43000 and the factor was focused at pH 6.6-6.8 in the chromatofocusing procedure. The MChF was protease sensitive but resistant to neuraminidase treatment, and it was stable by heating at 80 degrees C for 15 min. The MChF-producing hybridomas established in this stud did not produce macrophage migration inhibitory factor (MIF), macrophage-activating factor (MAF) or interleukin 2, suggesting molecular nonidentity between MChF and these lymphokines. The MChF-producing T cell hybridomas reactive to specific antigens (PC) will be promising tools for analysis of molecular nature of MChF as well as molecular aspects of antigen recognition mechanism of T cells.

EL-4 and macrophages: generation of chemotactic monokines

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

Characterization of human lymphocyte derived chemotactic factors for mononuclear phagocytes--II. Chemical characterization

Supernatants of PHA-stimulated human mononuclear cells were fractionated by Sephadex G-100 chromatography and isoelectric focusing. Chemotactic activities for human mononuclear phagocytes were identified at various molecular weight ranges. Major activities were found at mol. wt 45, 30, 25, 18, 12.5, 8 and 6 K. After isoelectric focusing chemotactic activities were recovered predominantly at pH 3.7-5.5 and 7.8-8.5. Fractionation by high performance liquid chromatography (HPLC) on the molecular sieve column I-125 and basic ion exchange column SAX 300 confirmed these results. Furthermore, after absorption of crude supernatants on the reversed-phase column RP 300, chemotactic activity was recovered quantitatively and thus could be separated from the bulk of other materials. In kinetic experiments supernatants were harvested after 5, 27, 42 and 63 hr and fractionated on a molecular sieve column. It was found that only low molecular weight chemotactic activity was released after 5 hr. After 27 hr most activity was found between 10-20,000 after 42 hr activity was found over the whole fractionation range. It is concluded that multiple molecular species of chemotactic factors acting on mononuclear phagocytes are released by activated lymphocyte cultures, whose chemical nature and function remains to be studied.

Characterization of human lymphocyte derived chemotactic factors for mononuclear phagocytes--I. Production and detection

Human peripheral blood mononuclear cells were isolated on a large scale by leukapheresis of either individual donors or pooled cell concentrates supplied by a local blood bank. Optimal conditions with respect to cell density, lectin (soluble and insoluble Concanavalin A; phytohemagglutinin) concentration and culture time were established for monocyte chemotactic factor (LMCF) production. LMCF was assayed on highly purified human monocytes/macrophages which had been kept in culture up to 4 days for optimal expression of response to LMCF. Chemotaxis assays were performed in a novel type multichamber assembly and migrated cells were enumerated by enzyme-linked immunosorbent assay. Based on the described methodology it is possible to produce litre quantities of LMCF and assay large numbers of samples both of which are prerequisites for chemical and functional characterizations of LMCF.