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The aim of this investigation was to reveal the regulatory properties of bacteriophage preparations in a model of mitogen-induced splenocyte proliferation in mice. We showed that sepharose 4B-purified preparations of the Staphylococcus aureus phage A20/R exhibited costimulatory activity in splenocyte proliferation induced by suboptimal (0.25 μg/ml) concentrations of ConA. On the other hand, the purified phage fraction was regulatory with regard to splenocyte proliferation induced by the optimal (2.5 μg/ml) ConA concentration. We also showed that the phage preparation can elicit IL-6 production in splenocyte cultures and enhance ConA-induced production of that cytokine. Furthermore, the phages preferentially induced IL-6 production in adherent splenocytes and increased levels of that cytokine in cultures of peritoneal cells from mice and rats. This phenomenon may explain the costimulatory activity of phages in the model described.
Pichia pastoris secretes few native proteins. However, the more than 1 g 1-1 of extracellularly expressed mannan interfered with the purification of our extracellularly expressed, non-glycosylated recombinant protein. Concanavalin A-agarose removed more than 95% of the unwanted mannan as monitored by phenol reaction. A 13C-based NMR assay confirmed this improvement. Concanavalin A-agarose can assist the purification of extracellular expressed, non-glycosylated proteins from yeasts.
Antipsychotic drugs are widely used to alleviate a number of psychic disorders and have been found to modulate some immune parameters, but the molecular mechanism of their action on the proliferative activity has been poorly recognized. In the present study, we investigated effects of various antipsychotics on the proliferative activity of lymphocytes stimulated by concanavalin A (Con A) and lipopolysaccharide (LPS). Chlorpromazine (3x10-6 - 10-4M) showed the most potent effect in inhibiting 3H-thymidine incorporation into C57BL/6 mouse spleen cells stimulated by Con A and LPS. Treatment of the cells with thioridazine (10-5 - 10-4M), promazine (10-5 - 10-4M), haloperidol (10-5 - 10-4M), risperidone (10-5 - 10-4M), raclopride (3x10-5 - 10-4M), remoxipride (3x10-5 - 10-4M) and clozapine ( 3x10-5 - 10-4M), but not with sulpiride (10-7 - 10-4M), suppressed proliferative activity of splenocytes after Con A stimulation. On the other hand, LPS-induced proliferation of splenocytes was inhibited by clozapine, promazine, thioridazine and haloperidol, but not by risperidone, remoxipride, sulpiride and raclopride. In the next part of the study, the influence of some kinase modulators on chlorpromazine- and clozapine-evoked inhibition of the proliferative activity of splenocytes was determined. Wortmannin, a selective phosphatidylinositol 3-kinase (PI3-K) inhibitor, blocked chlorpromazine and clozapine inhibitory effect on the mitogen-stimulated splenocyte proliferation. The involvement of PI 3-K /protein kinase B (PKB, Akt) pathway was confirmed by the results of the Western blot study, which showed that both drugs increased the level of active phospho-Ser-473 Akt, without changing the total Akt level, and decreased the level of active, nonphosphorylated glycogen synthase kinase-3 (GSK-3ß). Additionally, we have found that chlorpromazine action was also attenuated by a selective p-38-MAPK inhibitor, while clozapine effect was suppressed by a protein kinase C (PKC) activator. The obtained results indicated that atypical antipsychotic drugs markedly inhibited the proliferative activity of splenocytes only after ConA stimulation. Inhibition of the proliferative capability of splenocytes by chlorpromazine and clozapine resulted mainly from the activation of PI3-K/Akt pathway.
The ef fect of in su lin, wheat aerm ag glu ti nin (WGA), pea nut ag glu ti nin (PNA) and concanavalin A (ConA) on [ 3H]glucosamine incorporation into pericellular glyco­saminoglycans (GAGs) was investigated in two lines of cultured human dermal fibroblasts. Insulin and WGA stimulated [3H]glucosamine incorporation into hyalu­ronic acid (HA) and heparan sul phate (HS) with out any al ter ation of chondroitin sul­phate (CS) and dermatan sul phate (DS) con tents. ConA in creased [ 3H]glucosamine in- cor po ra tion into HS, CS and DS, but had no ef fect on [ 3H]glucosamine in cor po ra tion into HA. PNA af fected nei ther the con tent, nor the com po si tion of GAGs. In con trast to PNA, ConA and WGA stimulated glycolysis and demonstrated an evident anti­proliferative ef fect on der mal fibroblasts. Thus, both the in su lin-like ac tion of WGA and ConA on cul tured der mal fibroblasts and the dif fer ences be tween the ef fects of lectins on mod u la tion of GAGs syn the sis ap pear to be de ter mined by their chem i cal structure.
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