Hierarchy of cytotoxic T cell clones. II. Intraclonal triggering of lysis by hapten-specific CTL

Cells from clones of anti-hapten murine cytotoxic T lymphocytes (CTL) can act as both target and effector cells, but will not lyse members of the same clone. The effect of haptenation on the cytolytic activity of anti-fluorescein (FL) and anti-trinitrophenol (TNP) CTL clones was examined. Treatment of anti-FL clones with fluorescein isothiocyanate or anti-TNP clones with trinitrobenzene sulphonic acid induces these clones to kill in an antigen-independent fashion. Targets killed by the haptenated CTL included syngeneic and allogeneic B lymphocyte blast cells, P815, YAC-1 and in one case human GM 4072 tumor cells. The importance of CD8 and T cell receptor (TCR) occupancy is demonstrated by the ability to block autotriggering by antibody directed against Ly 2 and the TCR. The results demonstrate that effects other than antigen recognition of the target play a role in the final outcome of effector-target cell interactions and provide a mechanism which could lead to autodestruction and immunosuppression particularly in some types of viral infection.     

Über den Gehalt an auxin- und gibberellinähnlichen Stoffen bei jarowisierten und nicht jarowisierten Embryonen von Sommer- und Winterweizen

V jarovisovaných a nejarovisovaných obilkách jedné ozimé a jedné jarní odr?dy p?enice byly chromatograficky stanoveny látky typu auxin? a giberelin?. Chromatogramy byly vyhodnoceny pomocí biologických test?. U ozimé odr?dy jsme nena?li rozdíly v rozlo?ení r?stových látek mezi jarovisovanou a nejarovisovanou variantou. U jarní odr?dy jsme rozdíly na?li. Na základě výsledk? soudíme, ?e rozdíly mezi oběma variantami jarní odr?dy byly zp?sobeny nespecifickým p?sobením nízké teploty a ?e proces jarovisace není kausálně spjat se změnami hladiny r?stových látek.     

Function of the delipidated beta-adrenergic receptor appears to require a fatty acid or a neutral lipid in addition to phospholipids

Detergent-solubilized preparations of the beta-adrenergic receptor (R) and of the guanyl nucleotide binding proteins (Gs) were extensively treated to remove phospholipids and cholesterol. Reconstitution of an R-Gs system was subsequently performed in the presence of a mixture of natural phosphatidylethanolamine, phosphatidylcholine and phosphatidylserine or the synthetic dioleoyl derivatives of the same phospholipids. In both cases, an additional lipid was required for the agonist-dependent activation of Gs. The requirement could be fulfilled by alpha-tocopherol, or by unsaturated fatty acids such as oleic acid. Inclusion of this non-phosphorylated lipid in the reconstituted system enhanced the isoproterenol-dependent activation of Gs by guanosine 5'-O-[gamma-thio]triphosphate 16-33-fold. The rate of activation was largely dependent on the addition of the agonist. Efficient functional reconstitution of R-Gs was thus achieved in a totally defined lipid system. Additional studies of the reconstituted system and of the native membrane led to the notion that the non-phosphorylated lipid plays a role in the function of the hormone-R complex.