• MeSH
• diferenciační antigeny T-lymfocytů imunologie   metabolismus   MeSH
• dipeptidylpeptidasa 4 * imunologie   metabolismus   MeSH
• klinické zkoušky jako téma MeSH
• konformace proteinů MeSH
• molekulární konformace MeSH
• nežádoucí účinky léčiv MeSH

The C-type lectin-like receptors include the Nkrp1 protein family that regulates the activity of natural killer (NK) cells. Rat Nkrp1a was reported to bind monosaccharide moieties in a Ca2+-dependent manner in preference order of GalNac > GlcNAc > Fuc > Gal > Man. These findings established for rat Nkrp1a have been extrapolated to all additional Nkrp1 receptors and have been supported by numerous studies over the past two decades. However, since 1996 there has been controversy and another article showed lack of interactions with saccharides in 1999. Nevertheless, several high affinity saccharide ligands were synthesized in order to utilize their potential in antitumor therapy. Subsequently, protein ligands were introduced as specific binders for Nkrp1 proteins and three dimensional models of receptor/protein ligand interaction were derived from crystallographic data. Finally, for at least some members of the NK cell C-type lectin-like proteins, the "sweet story" was impaired by two reports in recent years. It has been shown that the rat Nkrp1a and CD69 do not bind saccharide ligands such as GlcNAc, GalNAc, chitotetraose and saccharide derivatives (GlcNAc-PAMAM) do not directly and specifically influence cytotoxic activity of NK cells as it was previously described.

• MeSH
• buňky NK * chemie   imunologie   metabolismus   MeSH
• CD antigeny * chemie   imunologie   metabolismus   MeSH
• diferenciační antigeny T-lymfocytů * chemie   imunologie   metabolismus   MeSH
• krysa rodu rattus MeSH
• lektinové receptory NK-buněk - podrodina B * chemie   imunologie   metabolismus   MeSH
• lektiny typu C * chemie   imunologie   metabolismus   MeSH
• lidé MeSH
• oligosacharidy * chemie   imunologie   metabolismus   MeSH
• terciární struktura proteinů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The binding of monosaccharides and short peptides to lymphocyte receptors (human CD69 and rat NKR-P1A) was first reported in 1994 and then in a number of subsequent publications. Based on this observation, numerous potentially high-affinity saccharide ligands have been synthesized over the last two decades in order to utilize their potential in antitumor therapy. Due to significant inconsistencies in their reported binding properties, we decided to re-examine the interaction between multiple ligands and CD69 or NKR-P1A. Using NMR titration and isothermal titration calorimetry we were unable to detect the binding of the tested ligands such as N-acetyl-D-hexosamines and oligopeptides to both receptors, which contradicts the previous observations published in more than twenty papers over the last fifteen years.

• MeSH
• CD antigeny metabolismus   MeSH
• diferenciační antigeny T-lymfocytů metabolismus   MeSH
• krysa rodu rattus MeSH
• lektiny typu C metabolismus   MeSH
• lidé MeSH
• oligopeptidy chemická syntéza   farmakologie   MeSH
• polysacharidy chemická syntéza   farmakologie   MeSH
• receptory imunologické metabolismus   MeSH
• rekombinantní proteiny metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

NK cells represent a potential tool for adoptive immunotherapy against tumors. Membrane-bound Hsp70 acts as a tumor-specific marker enhancing NK cell activity. Using flow cytometry the effect of in vitro stimulation with IL-2 or IL-15 alone or in combination with Hsp70-derived 14-mer peptide (TKD) on cell surface expression of NK activatory receptors (CD16, NKG2D, NKG2C, NKp46, NKp44, NKp30, KIR2DL4, DNAM-1, and LAMP1) and NK inhibitory receptors (NKG2A, KIR2DL2/L3, LIR1/ILT-2, and NKR-P1A) in healthy individuals was studied. Results were expressed as the percentage of receptor expressing cells and the amount of receptor expressed by CD3(-)CD56(+) cellular population. CD94, NKG2D, NKp44, NKp30, KIR2DL4, DNAM-1, LAMP1, NKG2A, and NKR-P1A were upregulated after the stimulation with IL-2 or IL-15 alone or in combination with TKD. KIR2DL2/L3 was upregulated only by IL-15 and IL-15/TKD. Concurrently, an increase in a number of NK cells positive for CD94, NKp44, NKp30, KIR2DL4, and LAMP1 was observed. IL-15 and IL-15/TKD caused also cell number rise positive for KIR2DL2/L3 and NKR-P1A. Cell number positive for NKG2C and NKG2A was increased only by IL-2 and IL-2/TKD. The diverse effect of IL-2 or IL-15 w or w/o TKD on cell surface expression was observed in CD16, NKp46, and LIR1/ILT-2.

• MeSH
• buňky NK účinky léků   metabolismus   MeSH
• diferenciační antigeny T-lymfocytů metabolismus   MeSH
• interleukin-15 farmakologie   MeSH
• interleukin-2 farmakologie   MeSH
• kultivované buňky MeSH
• lektinové receptory NK-buněk - podrodina B metabolismus   MeSH
• lektinové receptory NK-buněk - podrodina C metabolismus   MeSH
• lektinové receptory NK-buněk - podrodina K metabolismus   MeSH
• leukocyty mononukleární účinky léků   metabolismus   MeSH
• lidé MeSH
• membránové glykoproteiny asociované s lyzozomy metabolismus   MeSH
• peptidy chemie   farmakologie   MeSH
• proteiny tepelného šoku HSP70 chemie   MeSH
• receptor 1 spouštějící přirozenou cytotoxicitu metabolismus   MeSH
• receptor 2 spouštějící přirozenou cytotoxicitu metabolismus   MeSH
• receptor 3 spouštějící přirozenou cytotoxicitu metabolismus   MeSH
• receptory IgG metabolismus   MeSH
• receptory KIR2DL2 MeSH
• receptory KIR2DL4 metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The biology of T-cell acute lymphoblastic leukemia (ALL) is characterized by functional pre-T-cell receptor (TCR) signaling. Non-T-cell activation linker (NTAL) is a nonenzymatic transmembrane adaptor molecule that is involved in the proximal signaling of lymphocytes. In our previous work, we found an association between high NTAL expression in T-cell ALL blasts and a favorable response to initial glucocorticoid treatment. In the present study, we confirm our previous observation in an experimental model. In addition, the molecular mechanism of the contribution of NTAL to malignant T-cell ALL blast signaling and to methylprednisolone-induced cell death is analyzed. In the in vitro experiments, we used the T-cell ALL Jurkat cell line (Jurkat/wt) and derived Jurkat cell line with stable NTAL expression (Jurkat/NTAL(+)). Cell signaling and cell death after methylprednisolone treatment and after TCR stimulation were analyzed using flow cytometry, Western blot, and quantitative polymerase chain reaction. Jurkat/NTAL(+) cells are significantly more sensitive to both methylprednisolone treatment and TCR-induced stimulation. In addition, after TCR stimulation, Jurkat/NTAL(+) cells show a higher level of intracellular extracellular signal-regulated kinase 1/2 (ERK) phosphorylation and increased expression of the CD69 activation marker on the cell surface than the Jurkat/wt cells. The ERK inhibitor U0126 almost completely abrogates TCR-induced cell death and, importantly, reverses the sensitizing effect of the NTAL protein on methylprednisolone-induced cell death. In conclusion, NTAL acts as a tumor suppressor that enhances the proximal signaling of leukemic blasts. The key downstream molecule responsible for the biological effect of TCR signaling is ERK. Higher ERK phosphorylation leads to enhanced cell death after TCR stimulation and increases cell sensitivity to methylprednisolone-induced cell death.

• MeSH
• adaptorové proteiny signální transdukční fyziologie   MeSH
• apoptóza účinky léků   fyziologie   MeSH
• butadieny farmakologie   MeSH
• CD antigeny metabolismus   MeSH
• chemorezistence účinky léků   MeSH
• diferenciační antigeny T-lymfocytů metabolismus   MeSH
• fosforylace účinky léků   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• Jurkat buňky účinky léků   enzymologie   MeSH
• lektiny typu C metabolismus   MeSH
• lidé MeSH
• lymfoblastická leukemie-lymfom z prekurzorových T-buněk metabolismus   patologie   MeSH
• MAP kinasový signální systém účinky léků   MeSH
• methylprednisolon farmakologie   MeSH
• mitogenem aktivovaná proteinkinasa 1 antagonisté a inhibitory   metabolismus   MeSH
• mitogenem aktivovaná proteinkinasa 3 antagonisté a inhibitory   metabolismus   MeSH
• nádorové proteiny antagonisté a inhibitory   fyziologie   MeSH
• nitrily farmakologie   MeSH
• posttranslační úpravy proteinů účinky léků   MeSH
• receptory antigenů T-buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• techniky in vitro MeSH

Human immunodeficiency virus-1 (HIV-1) successfully escapes from host immune surveillance, vaccines and antiretroviral agents. The available antiretroviral compounds can only control viremia, but it is impossible to eliminate the virus from the organism, namely because HIV-1 provirus persists in the reservoir cells from which the virus repeatedly disseminates into new cells. Current therapeutic approaches, however, do not specifically address the stage of virus reactivation. Heme has been demonstrated as very efficient in inhibiting HIV-1 reverse transcription, while its derivative hemin ameliorated HIV-1 infection via induction of heme oxygenase-1. Normosang (heme arginate; HA) is a human hemin-containing compound used to treat acute porphyria. In this work, we studied the effects of HA in HIV-1-acutely infected T-cell lines, and in cell lines harboring either a complete HIV-1 provirus (ACH-2 cells) or an HIV-1 "mini-virus" (Jurkat clones expressing EGFP under control of HIV LTR). We demonstrate that HA inhibited HIV-1 replication during the acute infection, which was accompanied by the inhibition of reverse transcription. On the other hand, HA alone stimulated the reactivation of HIV-1 "mini-virus" and synergized with phorbol ester or TNF-α in the reactivation of HIV-1 provirus. The stimulatory effects of HA were inhibited by N-acetyl cysteine, suggesting an increased redox stress and activation of NF-κB. Further, HA induced expression of heme oxygenase-1 (HO-1) in ACH-2 cells, while HO-1 was found expressed in untreated Jurkat clones. Inhibitor of HO-1 activity, tin protoporphyrin IX, further increased HA-mediated reactivation of HIV-1 "mini-virus" in Jurkat clones, and this effect was also inhibited by N-acetyl cysteine. The stimulatory effects of HA on HIV-1 reactivation thus seem to involve HO-1 and generation of free radicals. Additionally, the effective concentrations of HA did neither affect normal T-cell activation with PMA nor induce activation of the unstimulated cells. In conclusion, HA appears to possess a combination of unique properties that could help to decrease the pool of latently infected reservoir cells, while simultaneously inhibiting HIV-1 replication in newly infected cells. Our results thus suggest a new direction to explore in treatment of HIV/AIDS disease.

• MeSH
• acetylcystein farmakologie   MeSH
• aktivace viru účinky léků   MeSH
• arginin farmakologie   MeSH
• buněčné linie MeSH
• CD antigeny metabolismus   MeSH
• diferenciační antigeny T-lymfocytů metabolismus   MeSH
• hem farmakologie   MeSH
• hemoxygenasa-1 antagonisté a inhibitory   metabolismus   MeSH
• HIV-1 účinky léků   fyziologie   MeSH
• Jurkat buňky MeSH
• latence viru účinky léků   MeSH
• látky proti HIV farmakologie   MeSH
• lektiny typu C metabolismus   MeSH
• lidé MeSH
• metaloporfyriny farmakologie   MeSH
• protoporfyriny farmakologie   MeSH
• proviry účinky léků   genetika   MeSH
• replikace viru účinky léků   MeSH
• reverzní transkripce účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This work reveals new structural relationships in the complex process of the interaction between activation receptors of natural killer cells (rat NKR-P1, human CD69) and novel bivalent carbohydrate glycomimetics. The length, glycosylation pattern and linker structure of receptor ligands were examined with respect to their ability to precipitate the receptor protein from solution, which simulates the in vivo process of receptor aggregation during NK cell activation. It was found that di-LacdiNAc triazole compounds show optimal performance, reaching up to 100% precipitation of the present protein receptors, and achieving high immunostimulatory activities without any tendency to trigger activation-induced apoptosis. In the synthesis of the compounds tested, two enzymatic approaches were applied. Whereas a β-N-acetylhexosaminidase could only glycosylate one of the two acceptor sites available with yields below 10%, the Y284L mutant of human placental β1,4-galactosyltransferase-1 worked as a perfect synthetic tool, accomplishing even quantitative glycosylation at both acceptor sites and with absolute regioselectivity for the C-4 position. This work insinuates new directions for further ligand structure optimisation and demonstrates the strong synthetic potential of the mutant human placental β1,4-galactosyltransferase-1 in the synthesis of multivalent glycomimetics and glycomaterials.

• MeSH
• aktivace lymfocytů účinky léků   imunologie   MeSH
• beta-N-acetylhexosaminidasy metabolismus   MeSH
• biomimetika metody   MeSH
• buňky NK chemie   účinky léků   imunologie   metabolismus   MeSH
• CD antigeny imunologie   metabolismus   MeSH
• diferenciační antigeny T-lymfocytů imunologie   metabolismus   MeSH
• galaktosyltransferasy genetika   metabolismus   MeSH
• imunoprecipitace MeSH
• krysa rodu rattus MeSH
• lektiny typu C agonisté   imunologie   metabolismus   MeSH
• lidé MeSH
• ligandy MeSH
• molekulární mimikry MeSH
• mutace MeSH
• placenta enzymologie   MeSH
• polysacharidy chemická syntéza   farmakologie   MeSH
• receptory buněk NK agonisté   imunologie   metabolismus   MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• těhotenství MeSH
• vazba proteinů účinky léků   imunologie   MeSH
• vazebná místa účinky léků   imunologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

On the basis of the highly branched ovomucoid-type undecasaccharide that had been shown previously to be an endogenous ligand for CD69 leukocyte receptor, a systematic investigation of smaller oligosaccharide mimetics was performed based on linear and branched N-acetyl-d-hexosamine homooligomers prepared synthetically using hitherto unexplored reaction schemes. The systematic structure-activity studies revealed the tetrasaccharide GlcNAcbeta1-3(GlcNAcbeta1-4)(GlcNAcbeta1-6)GlcNAc (compound 52) and its alpha-benzyl derivative 49 as the best ligand for CD69 with IC(50) as high as 10(-9) M. This compound thus approaches the affinity of the classical high-affinity neoglycoprotein ligand GlcNAc(23)BSA. Compound 68, GlcNAc tetrasaccharide 52 dimerized through a hydrophilic flexible linker, turned out to be effective in activating CD69(+) lymphocytes. It also proved efficient in enhancing natural killing in vitro, decreasing the growth of tumors in vivo, and activating the CD69(+) tumor infiltrating lymphocytes examined ex vivo. This compound is thus a candidate for carbohydrate-based immunomodulators with promising antitumor potential.

• MeSH
• acetylglukosamin analogy a deriváty   chemická syntéza   chemie   farmakologie   MeSH
• aktivace lymfocytů MeSH
• antitumorózní látky chemická syntéza   chemie   farmakologie   MeSH
• buňky NK účinky léků   imunologie   metabolismus   MeSH
• CD antigeny metabolismus   MeSH
• diferenciační antigeny T-lymfocytů metabolismus   MeSH
• dimerizace MeSH
• imunologické faktory chemická syntéza   chemie   farmakologie   MeSH
• krysa rodu rattus MeSH
• lektinové receptory NK-buněk - podrodina B metabolismus   MeSH
• lektiny typu C metabolismus   MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• ligandy MeSH
• melanom experimentální imunologie   patologie   MeSH
• molekulární mimikry MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• oligosacharidy chemická syntéza   chemie   farmakologie   MeSH
• rekombinantní proteiny chemie   MeSH
• sacharidové sekvence MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• publikace stažené z tisku MeSH
• techniky in vitro MeSH

CD69 is an earliest lymphocyte activation antigen and a universal leukocyte triggering molecule expressed at sites of active immune response. The binding of GlcNAc to the dimeric human CD69 was followed by equilibrium dialysis, fluorescence titration, and NMR. Clear cooperation was observed in the high-affinity binding (K(d) = 4.0 x 10(-7) M) of the carbohydrate to two subunits of the dimeric CD69 (Hill coefficient 1.94). A control monosaccharide ManNAc was not bound by human CD69, and both monosaccharides had no effects on the structure of the receptor. However, a monomeric CD69 obtained by mutating Q93 and R134 at the dimer interface exhibited a much lower affinity for GlcNAc (K(d) = 1.3 x 10(-5) M) and no cooperativity (Hill coefficient 1.07). Perturbation of the dimer interface resulted in a severe impairment of the signaling ability of cellular CD69 when cross-linked with an antibody or with a bivalent high-affinity N-acetylhexosamine dimer-based ligand. The availability of stable preparations of soluble CD69 receptor with well-documented ligand binding properties will be beneficial for immunological experiments evaluating the role of this antigen in the complex environment of the immune system. Moreover, such preparations in combination with efficient ligand mimetics able to both activate CD69(+) lymphocytes and to block undesired hyperactivation caused by other cellular ligands will also become indispensable tools in explaining the exact role of the CD69 antigen in the interaction between the tumor cell and the effector natural killer lymphocyte.

• MeSH
• CD antigeny chemie   metabolismus   MeSH
• diferenciační antigeny T-lymfocytů chemie   metabolismus   MeSH
• dimerizace MeSH
• hexosaminy chemie   MeSH
• Jurkat buňky MeSH
• lektiny typu C chemie   metabolismus   MeSH
• lidé MeSH
• ligandy MeSH
• molekulární modely MeSH
• podjednotky proteinů chemie   metabolismus   MeSH
• vazebná místa MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• publikace stažené z tisku MeSH

We have recently identified a new class of high affinity ligands for CD69 leukocyte membrane receptor, carboxylated calixarenes. Of the three compounds investigated here, thiacalix[4]arene had the highest affinity for CD69 in direct binding assays, and proved to be the most specific inhibitor of CD69 identified so far in receptor precipitation and cellular activation experiments. Carboxylated calixarenes also proved effective at protection of CD69(high) lymphocytes from apoptosis triggered by a multivalent ligand or antibody. Thus, carboxylated calixarenes set a new paradigm for noncarbohydrate ligands for CD69 making them attractive for protection of killer cells in combined animal tumor therapies.

• MeSH
• apoptóza MeSH
• CD antigeny metabolismus   MeSH
• diferenciační antigeny T-lymfocytů metabolismus   MeSH
• kalixareny chemie   metabolismus   MeSH
• krysa rodu rattus MeSH
• kyseliny karboxylové chemie   MeSH
• lektiny typu C metabolismus   MeSH
• lidé MeSH
• ligandy MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• publikace stažené z tisku MeSH