A macrophage derived blastogenic factor -MBF- induces cytokines and cytotoxic effectors in human peripheral blood mononuclear cells.

A soluble macrophage-derived blastogenic factor, previously reported as MBF, is secreted from macrophages activated with galactose oxidase. It was previously shown that MBF is able to induce IFN-gamma production and proliferation of T lymphocytes. In this study we found that MBF is able to induce in human peripheral blood mononuclear cells (PBMC) production of interleukin 1 (IL-1) beta, interleukin 2 (IL-2) and tumor necrosis factor (TNF) alpha and generation of MHC-unrestricted cytotoxic activity. The induction of killer cells is likely to rely on IFN-gamma production in that in PBMC treated with a monoclonal antibody (Mab) against IFN-gamma, the MBF induced cytotoxic activity was drastically reduced. A comparison of MBF induced cytotoxic effectors with those induced by IL-2 showed that both cytotoxic effectors pertain to NK lineage, in that they were CD3- and CD16+. On the contrary, the precursors of MBF and IL-2 induced killer cells were different; MBF cytotoxic precursor cells were highly sensitive to L-Leucine methyl ester (Leu-OME), a drug able to eliminate monocytes and NK cells, whereas IL-2 cytotoxic precursors were unaffected by this drug.     

Recombinant soluble Fcγ receptors: production, purification and biological activities

Soluble forms of low affinity receptors for the Fc portion of IgG circulate in body fluids and regulate immune functions. We describe the transfection, production and purification techniques which allow the preparation, at a laboratory scale, of milligram amounts of glycosylated recombinant mouse and human soluble Fcγ receptors. These recombinant products bind IgG and are biologically active on immune responses, like their normal counterparts.     

Assessment of the mutagenic, antimutagenic and cytotoxic activities of ethanolic extract of araticum (Annona crassiflora Mart. 1841) by micronucleus test in mice.

A typical Brazilian plant, araticum (Annona crassiflora Mart.), is widely used in humans as therapeutic medicine to treat several diseases such as diarrhea, rheumatism and syphilis. It contains acetogenins which present cytotoxic, antitumogenic, and antiparasitic properties. In this study, mutagenic, antimutagenic and cytotoxic effects of araticum leaves ethanolic extract were evaluated by micronucleus test in mice. To evaluate the mutagenic activity, animals were treated with ethanolic extract of araticum (EEA) using 10, 20, 50, 100 and 160 mg.kg(-1). For all doses, micronucleated polychromatic erythrocytes (MNPCE) frequency was evaluated at 24, 48 and 72 hours after treatment. To evaluate the antimutagenic activity, animals were treated with 10, 20, 50 and 100 mg.kg(-1) of EEA and 4 mg.kg(-1) of MMC simultaneously. The frequency of MNPCE was evaluated 36 hours after exposure. Cytotoxicity was evaluated by the polychromatic and normochromatic erythrocytes ratio (PCE/NCE). In the mutagenicity assessment, all doses of EEA resulted in no significant increase of MNPCE (P > 0.05), compared to solvent- control group. Regarding administration time, no significant difference among three evaluation periods was observed (P > 0.05). Such results indicate that EEA did not exert mutagenic activity. Cytotoxicity was evident in doses of 50, 100 and 160 mg.kg(-1) at 24 and 48 hours after exposure. Concerning antimutagenicity, except the 10 mg.kg(-1) co-administered with 4 mg/kg of MMC, all doses reduced significantly the frequency of MNPCE compared to the positive control group (P < 0.05). These results, therefore, indicate an antimutagenic activity of the EEA. Cytotoxicity was significantly increased (P < 0.01) at 100 mg.kg(-1) EEA doses co-administered with 4 mg.kg(-1) of MMC.     

Opossum adrenal medulla: II. Differentiation of the chromaffin cell

The ultrastructure of the opossum adrenal medulla was examined in its postnatal development. Maturation of chromaffin cells and genesis of chromaffin vesicles were of particular interest. The primitive sympathetic cell was seen to contain few organelles with no apparent polarity. Initial pheochromoblasts contained more organelles with some polarity. Endoplasmic reticulum and the Golgi complex increased as the pheochromoblasts matured, which suggested increased synthetic activity. Structures resembling Golgi/endoplasmic reticulum/lysosome (GERL) systems were seen in the pheochromoblasts. It is suggested that some of the components of the chromaffin vesicle may be processed by the GERL while others come directly through the Golgi complex. It is stressed that the developing pheochromoblast in the opossum presents an interesting model in which to study the genesis of the chromaffin vesicle.