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