Biological screening of selected Pacific Northwest forest plants using the brine shrimp (Artemia salina) toxicity bioassay.

The brine shrimp (Artemia salina) bioassay was used to screen 211 methanol extracts from 128 species of Pacific Northwest plants in search of general cytotoxic activity. Strong toxicity (LC50 < 100 µg/ml) was found for 17 extracts from 13 species, with highest activity observed for Angelica arguta roots at <10 µg/ml. Notably, four species of cedar trees and one of juniper in the family Cupressaceae dominated this group with LC50 for heartwood extracts ranging from 15 to 89 µg/ml.

Saponin Variants with Central Glycosidic Linkage Modifications Exhibit Distinct Conformations and Adjuvant Activities.

Immunological adjuvants such as the saponin natural product QS-21 help stimulate the immune response to co-administered antigens and have become increasingly important in the development of prophylactic and therapeutic vaccines. However, clinical use of QS21 is encumbered by chemical instability, dose-limiting toxicity, and low-yielding purification from the natural source. Previous studies of structure-activity relationships in the four structural domains of QS-21 have led to simplified, chemically stable variants that retain potent adjuvant activity and low toxicity in mouse vaccination models.

Design, synthesis, and immunologic evaluation of vaccine adjuvant conjugates based on QS-21 and tucaresol.

Immunoadjuvants are used to potentiate the activity of modern subunit vaccines that are based on molecular antigens. An emerging approach involves the combination of multiple adjuvants in a single formulation to achieve optimal vaccine efficacy. Herein, to investigate such potential synergies, we synthesized novel adjuvant conjugates based on the saponin natural product QS-21 and the aldehyde tucaresol via chemoselective acylation of an amine at the terminus of the acyl chain domain in QS saponin variants.

Development of a minimal saponin vaccine adjuvant based on QS-21.

Adjuvants are materials added to vaccines to enhance the immunological response to an antigen. QS-21 is a natural product adjuvant under investigation in numerous vaccine clinical trials, but its use is constrained by scarcity, toxicity, instability and an enigmatic molecular mechanism of action. Herein we describe the development of a minimal QS-21 analogue that decouples adjuvant activity from toxicity and provides a powerful platform for mechanistic investigations.

Immunization with N-propionyl polysialic acid-KLH conjugate in patients with small cell lung cancer is safe and induces IgM antibodies reactive with SCLC cells and bactericidal against group B meningococci.

Purpose: Polysialic acid (polySA) is a polymer side chain bound to the neural cell adhesion molecule that is extensively expressed on the surface of small cell lung cancer (SCLC) cells. In our previous study, a robust antibody response was noted in patients with SCLC after vaccination with 30 μg of keyhole limpet hemocyanin (KLH)-conjugated N-propionylated (NP-) polySA, but peripheral neuropathy and ataxia were detected in several vaccinated patients. The objectives of the current trial were to establish the lowest optimal dose and to confirm the safety of the induction of antibodies against polySA with the NP-polySA vaccine.

The known immunologically active components of Astragalus account for only a small proportion of the immunological adjuvant activity when combined with conjugate vaccines.

The 95 % ethanol extract of Astragalus has been demonstrated to have potent activity as an immunological adjuvant when administered with vaccines of various types. We endeavor here to identify the components of this extract that are responsible for this adjuvant activity. Mice were immunized with KLH conjugated to cancer carbohydrate antigens globo H and GD3 and cancer peptide antigen MUC1 combined with different Astragalus fractions or with commercially available Astragalus saponins and flavonoids.

Preclinical evaluation of the synthetic adjuvant SQS-21 and its constituent isomeric saponins.

The saponin fraction QS-21 from Quillaja saponaria has been demonstrated to be a potent immunological adjuvant when mixed with keyhole limpet hemocyanin conjugate vaccines, as well as with other classes of subunit antigen vaccines. QS-21 adjuvant is composed of two isomers that include the apiose and xylose forms in a ratio of 65:35, respectively. The chemical syntheses of these two isomers in pure form have recently been disclosed.

Biologics through chemistry: total synthesis of a proposed dual-acting vaccine targeting ovarian cancer by orchestration of oligosaccharide and polypeptide domains.

Carbohydrate and peptide-based antitumor vaccine constructs featuring clusters of both tumor associated carbohydrate antigens and mucin-like peptide epitopes have been designed, synthesized, and studied. The mucin-based epitopes are included to act, potentially, as T-cell epitopes in order to provoke a strong immune response. Hopefully the vaccine will simulate cell surface architecture, thereby provoking levels of immunity against cancer cell types displaying such characteristics.

Distinct domain-dependent effect of syntaxin1A on amiloride-sensitive sodium channel (ENaC) currents in HT-29 colonic epithelial cells.

The amiloride-sensitive epithelial sodium channel (ENaC), a plasma membrane protein mediates sodium reabsorption in epithelial tissues, including the distal nephron and colon. Syntaxin1A, a trafficking protein of the t-SNARE family has been reported to inhibit ENaC in the Xenopus oocyte expression and artificial lipid bilayer systems. The present report describes the regulation of the epithelial sodium channel by syntaxin1A in a human cell line that is physiologically relevant as it expresses both components and also responds to aldosterone stimulation.

Epithelial sodium channel is regulated by SNAP-23/syntaxin 1A interplay.

Sodium-selective amiloride-sensitive epithelial channel (ENaC) located in the apical membrane is involved in the reabsorption of sodium in tight epithelia. The soluble N-ethylmaleimide-sensitive attachment receptors (SNAREs) mediate vesicle trafficking in a variety of cell systems. Syntaxin (a t-SNARE) has been shown to interact with and functionally regulate a number of ion channels including ENaC.

Rab4GTPase modulates CFTR function by impairing channel expression at plasma membrane.

Cystic fibrosis (CF), an autosomal recessive disorder, is caused by the disruption of biosynthesis or the function of a membrane cAMP-activated chloride channel, CFTR. CFTR regulatory mechanisms include recruitment of channel proteins to the cell surface from intracellular pools and by protein-protein interactions. Rab proteins are small GTPases involved in regulated trafficking controlling vesicle docking and fusion.

Rab4 GTP/GDP modulates amiloride-sensitive sodium channel (ENaC) function in colonic epithelia.

The sodium-selective amiloride-sensitive epithelial sodium channel (ENaC) mediates electrogenic sodium re-absorption in tight epithelia. ENaC expression at the plasma membrane requires regulated transport, processing, and macromolecular assembly of subunit proteins in a defined and highly compartmentalized manner. Ras-related Rab GTPases monitor these processes in a highly regulated sequence of events.