Identification of Tumor Antigens in the HLA Peptidome of Patient-derived Xenograft Tumors in Mouse

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Highlights

• •Sufficient tumor tissues are often unavailable large HLA peptidome discovery.
• •Using patient derived xenograft (PDX) tumors can overcome this limitation.
• •The large PDX HLA peptidomes expand significantly those of the original biopsies.
• •The HLA peptidomes of the PDX tumors included many tumor antigens.

     

β-adrenoceptors in human tracheal smooth muscle: characteristics of binding and relaxation

Specific binding of [¹²⁵I]-(−)-cyanopindolol to human tracheal smooth muscle membranes was saturable, stereo-selective and of high affinity (K_d=5.3±0.9 pmol/l and R_T=78±7fmol/g tissue). The β₁-selective antagonists atenolol and LK 203-030 inhibited specific [¹²⁵I]-(−)-cyanopindolol binding according to a one binding site model with low affinity in nearly all subjects, pointing to a homogeneous β₂-adrenoceptor population. In one subject using LK 203-030 a small β-adrenoceptor subpopulation could be demonstrated. The beta-mimetics isoprenaline, fenoterol, salbutamol and terbutaline recognized high and low affinity agonist binding sites. Isoprenaline's pK_H- and pK_L- values for the high and low affinity sites were 8.0±0.2 and 5.9±0.3 respectively. In functional experiments isoprenaline relaxed tracheal smooth muscle strips having intrinsic tone with a pD₂-value of 6.63±0.19.     

Morphine and Enkephalins Potently Inhibit [3H]Noradrenaline Release from Rat Brain Cortex Synaptosomes: Further Evidence for a Presynaptic Localization of μ-Opioid Receptors

Synaptosomes prepared from rat cerebral cortex and labeled with [3H]noradrenaline (NA) were superfused with calcium-free Krebs-Ringer-bicarbonate medium and exposed to 10 mM K+ plus 0.1 mM Ca2+ so that [3H]NA release was induced. 6,7-Dihydroxy-N,N-dimethyl-2-aminotetralin (TL-99) strongly inhibited synaptosomal K+-induced [3H]NA release (EC50 = 5-10 nM) by activating alpha 2-adrenoceptors. Release was also inhibited (maximally by 40-50%) by morphine (EC50 = 5-10 nM), [Leu5]enkephalin (EC50 = approximately 300 nM), [D-Ala2,D-Leu5]enkephalin (DADLE), and Tyr-D-Ala-Gly-(NMe)Phe-Gly-ol (DAGO) (EC50 values = approximately 30 nM). In contrast to the mu-selective opioid receptor agonists morphine and DAGO, the highly delta-selective agonist [D-Pen2,D-Pen5]enkephalin (1 microM) did not affect [3H]-NA release. Furthermore, the inhibitory effect of DADLE, an agonist with affinity for both delta- and mu-opioid receptors, was antagonized by low concentrations of naloxone. The findings strongly support the view that, like alpha 2-adrenoceptors, mu-opioid receptors mediating inhibition of NA release in the rat cerebral cortex are localized on noradrenergic nerve terminals.     

Changes in the integrity of large unilamellar vesicles due to their interaction with tobacco cell suspensions

Negatively charged large unilamellar vesicles (LUV) were incubated with tobacco (Nicotiana tabacum var. xanthi) cell suspensions and with the cell-free medium of the cell suspensions. The extent of cell-LUV interaction was determined by the leakage of the LUV contents. Cells enhanced the leakage of LUV contents and this effect increased with cell age. Addition of polylysine to the reaction mixture increased even further the leakage of the LUV contents. The cell-free medium of the cell suspension also affected the integrity of the LUV. Cell-free medium, by itself, promoted leakage of LUV contents and caused a reduction in the leakage exerted by polylysine. Centrifugation (8000g) of the cell-free medium decreased its effect, heat treatment (122°C) did not alter its effect and sonication enhanced it. The effects of the cell-free medium are attributed to the presence of cell wall debris of disintegrated cells.     

ATP-induced ΔpH formation in chloroplast ATP synthase proteoliposomes

Summary A procedure to reconstitute CF₀CF₁ proteoliposomes by gel filtration through a Sephadex-column pre-equilibrated with valinomycin and potassium is described. Proteoliposomes reconstituted by this procedure catalyze an ATP-induced pH of 2.5 to 3.5 units. pH was measured with either 9-aminoacridine or with the pH indicator pyranine trapped inside the proteoliposomes. CF₀CF₁ proteoliposomes prepared by conventional techniques catalyzed an ATP-induced formation, but were unable to catalyze an ATP-induced pH even in the presence of valinomycin.The ATP-induced pH was sensitive to uncouplers and energy transfer inhibitors and was increased at low temperatures. It is suggested that ATP-induced pH was observed in these proteoliposomes due to the efficient removal of intravesicular ammonium introduced with the CF₀CF₁ preparation. The ammonium acted as an internal buffer, and thus prevented an observable pH formation.     

Data transfer from Beckman LS 5800 liquid scintillation counters to IBM personal computers

This communication describes a short routine in BASICA for theIBM-PC, written to collect data from a Beckman liquid scintillationcounter. In the form presented here the routine converts incomingbytes into separate lines and saves these lines in a file. Thereare many possible applications for further use of the data inthese files. A few suggestions are given as to the format inwhich data can be stored and how to process these data automaticallyafter all samples have been counted. The only hardware neededis an asynchronous communications adapter for the IBM-PC andan RS232 cable. Received on July 27, 1985; accepted on August 2, 1985     

Hormone-responsive cells derived from human dental papilla: Characterization in vitro and in vivo in diffusion chambers

Summary Cells of the dental papilla are capable of odontoblastic, fibroblastic, and endothelial differentiation and formation of dentin and the dental pulp. In the present study dental papilla cells, obtained from human tooth buds (HDP cells), were cultured in vitro through 3 to 7 passages. After exposure to prostaglandin E₂ there was a marked decrease in intracellular cyclic AMP (cAMP) levels as compared to hormone-free controls. Parathyroid hormone and calcitonin had stimulatory effects with 1 and 2 log increases in cAMP, respectively. The HDP cells showed moderate activity of alkaline phosphatase, 1 log higher than that of hamster kidney fibroblasts (BHK 13) and 1 log lower than that of osteoblastic osteosarcoma cells (ROS 17/2). When cultured for 4 or 8 wk in diffusion chambers (DC) implanted in athymic mice, many of the HDP cells underwent odontoblastic morphodifferentiation with very long, single processes extending into the matrix. This matrix contained banded and unbanded collagen fibers. Neither light nor electron microscopy of the DC content revealed mineral deposits. These results suggest that HDP cells have an intrinsic potential for partial odontoblastic differentiation; inductive signals like those originating from odontogenic epithelium are probably essential for the completion of hard tissue formation.