The aim was to study the role of major histocompatibility complex (MHC), in mice named H-2, during early allogeneic reactions (AR) of brain cortex cells or lymphocytes. We used neuronal and glial enriched perikarya, spleen and thymus lymphocytes or their subpopulations. Rat AR was also assayed between C-6 astrocytoma cells and spleen lymphocytes. We demonstrated that: 1) H-2 dependent stimulation of Na+,K+-ATPase and ouabain- sensitive K+-dependent p-nitrophenylphosphatase (K+-pNPPase) activities represented specific response in both AR of unseparated brain cells or lymphocytes. On the other hand, non-specific AR-induced stimulation of Ca2 + - ATPase activity was observed. 2) Allogeneic enriched glial fractions reacted similarly by the same enzyme activation in contrast to no change in AR between enriched neuronal fractions. Allorecognition ability of glial cells was confirmed by AR between C-6 astrocytoma cells and lymphocytes. 3) Mature thymus lymphocytes exerted alloreactivity by specific activation of Na+,K+-ATPase or K+-pNPPase, in contrast to no change in AR between immature lymphocyte subpopulations. 4) MHC Class II monoclonal antibody inhibited Na+,K+-ATPase and K+-pNPPase activities in brain cells as well as in thymus and spleen lymphocytes in a dose-dependent manner. Results support former studies about alloantigen-induced uncoupling in brain oxidative cortex metabolism (Kovářů Med. Biol. 58: 273, 1980) via Na+,K+-ATPase and K+-pNPPase inhibition by mechanism which can mimic MHC restriction.
Gel electrophoresis of DNA was used for estimation of DNA changes caused in C6 glioma cells by treatment with psychotropic drugs (imipramine, amitryptiline and fluoxetine). Some discrete bands containing a population of short DNA fragments appeared after 1 and 5 days of cultivation. Apoptotic DNA breaks were verified at single cell level using the TUNEL test in cells treated with fluoxetine.
An allogeneic reaction among brain cortex cells (mixed reaction) was demonstrated previously by H-2 alloantigen- induced uncoupling of oxidative metabolism (Kovářů Med. Biol. 58: 273, 1980). In the present study we have demonstrated that alloantigen already increased cell surface Na + ,K+-ATPase activity after 100 min when the enzyme activation was highest at Mg2+/ATP ratio 4: 1. The allogeneic cell reaction was accompanied by an elevation of membrane lipid fluidity and probably also by a thermotropic lipid phase transition which might influence the membrane lipid-dependent Na+,K+-ATPase activity, while Mg2+-ATPase remained unaffected. Furthermore, the effects of proteins and peptides released into the supernatant during the allogeneic reaction were analyzed in brain cortex cells. One of the isolated active peptide fractions, Fa (m.w. lower than 2.5 kD), was able to enhance Na+,K+-ATPase activity as well as to block K+-evoked O2 uptake by brain cortex cells. Thus the Fa fraction simulated primary allorecognition events. The data indicate that various brain cell surface domains were influenced by a regulatory peptide fraction of the cytokine type during the early phase of allogeneic reaction. Allorecognition among brain cortex cells is directed against functionally important metabolic reactions.
Ergot alkaloids (EAs), products of Claviceps spp., are widely used in various fields of clinical medicine (neurology, psychiatry, endocrinology). In the present work we studied the neuroimmunomodulative effect of EAs on activation of NK cells and their signalling pathways. Furthermore, the killing capability of rat NK cells in vitro was examined in the presence of glycosidic derivatives of elymoclavine, agroclavine, and liposome-encapsulated EAs. The engagement of appropriate NK cell membrane receptors by EAs cause an indirect enhancement of adenylyl cyclase system through inhibition of G-protein a 1,2-subunit (up to 50 % of control values). All of the tested EAs enhanced the rat NK cell-mediated cytotoxic activity in vitro, particularly against target cells of astrocyte origin (C-6 glioma). The present results argue for a possible EA immunomodulatory role of cell-mediated immunity in tumour regression processes.
This study describes the effects of cytokine peptides released into the supernatant during an early allogeneic reaction (AR) of mouse spleen lymphocytes or brain cortex cells which differ in their major histocompatibility complex (MHC). The peptides were isolated by ultrafiltration, liquid chromatography and HPLC. We found that both peptides stimulated the cell surface Na+,K+-ATPase and Ca2+-ATPase activities of quiescent spleen lymphocytes in vitro and mimicked early allogeneic cell interactions. Both brain and spleen AR peptides inhibited Concanavalin A-stimulated spleen lymphocyte proliferation, whereas 3H-TdR incorporation into DNA of the E7 neuroblastoma cell Une was stimulated by these peptides. The peptide isolated from the supernatant of the allogeneic brain ceU reaction inhibited phagocytosis in phorbol myristate-stimulated LA5-9/8 mouse macrophage cell line. Immunosuppressive activity of spleen AR peptide is supported by inhibition of spontaneous E rosette formation by lymphocytes. The immunosuppressive effect of isolated peptide cytokines on lectin-activated lymphocytes was comparable with the serum thymic factor (FTS, Lenfant et al. 1983). These changes demonstrate the pleiotropic cytokine actions mediated by plasma membrane of immune system and brain cells.