Antigen-reactive T cell enrichment for direct, high-resolution analysis of the human naive and memory Th cell repertoire.

Ag-specific CD4(+) T cells orchestrating adaptive immune responses are crucial for the development of protective immunity, but also mediate immunopathologies. To date, technical limitations often prevented their direct analysis. In this study, we report a sensitive flow cytometric assay based on magnetic pre-enrichment of CD154(+) T cells to visualize rare Ag-reactive naive and memory Th cells directly from human peripheral blood.

Imaging of firefly luciferase activity under antiangiogenic therapy in a heat shock protein 70-transfected melanoma tumor model.

We investigated the effect of targeted gene therapy on heat shock protein 70 (Hsp70) expression in a melanoma tumor model (M21). M21 cells transfected with a plasmid containing the firefly luciferase reporter gene (ffluc), whose expression is driven by the hsp70 (hspa1b) or the cytomegalovirus (CMV) promoter, were grown to a size of 600 mm3. Five animals in each group were intravenously treated with an Arg-Gly-Asp peptide-nanoparticle/Raf-1 kinase inhibitor protein [RGD-NP/RAF(-)] complex.

Effect of antiangiogenic therapy on luciferase activity in a cytomegalovirus- or HSP70-promoter-transfected M21 tumor model.

We investigated the effect of targeted gene therapy on heat shock protein 70 expression (Hsp70) and protein production (HSP70) in a melanoma tumor model (M21; M21-L). M21 and M21-L cells transfected with a plasmid containing the Hsp70 (Hspa1b) or the cytomegalovirus (CMV) promoter and the luciferase reporter gene were injected into mice; the resulting tumors grew to a size of 650 mm(3). Mice (five per group) were intravenously treated with an Arg-Gly-Asp peptide-nanoparticle/Raf-1 kinase inhibitor protein complex [RGD-NP/RAF(-)] or with a nanoparticle control.

Spore formation in Myxococcus xanthus is tied to cytoskeleton functions and polysaccharide spore coat deposition.

Myxococcus xanthus is a Gram-negative bacterium that differentiates into environmentally resistant spores. Spore differentiation involves septation-independent remodelling of the rod-shaped vegetative cell into a spherical spore and deposition of a thick and compact spore coat outside of the outer membrane. Our analyses suggest that spore coat polysaccharides are exported to the cell surface by the Exo outer membrane polysaccharide export/polysaccharide co-polymerase 2a (OPX/PCP-2a) machinery.

A novel "four-component" two-component signal transduction mechanism regulates developmental progression in Myxococcus xanthus.

Histidine-aspartate phosphorelays are employed by two-component signal transduction family proteins to mediate responses to specific signals or stimuli in microorganisms and plants. The RedCDEF proteins constitute a novel signaling system in which four two-component proteins comprising a histidine kinase, a histidine-kinase like protein, and two response regulators function together to regulate progression through the elaborate developmental program of Myxococcus xanthus. A combination of in vivo phenotypic analyses of in-frame deletions and non-functional point mutations in each gene as well as in vitro autophosphorylation and phosphotransfer analyses of recombinant proteins indicate that the RedC histidine kinase protein autophosphorylates and donates a phosphoryl group to the single domain response regulator, RedF, to repress progression through the developmental program.