Peter Gerber

Biomedical nanoparticles modulate specific CD4+ T cell stimulation by inhibition of antigen processing in dendritic cells

Abstract Understanding how nanoparticles may affect immune responses is an essential prerequisite to developing novel clinical applications. To investigate nanoparticle-dependent outcomes on immune responses, dendritic cells (DCs) were treated with model biomedical poly(vinylalcohol)-coated super-paramagnetic iron oxide nanoparticles (PVA-SPIONs). PVA-SPIONs uptake by human monocyte-derived DCs (MDDCs) was analyzed by flow cytometry (FACS) and advanced imaging techniques. Viability, activation, function, and stimulatory capacity of MDDCs were assessed by FACS and an in vitro CD4+ T cell assay. PVA-SPION uptake was dose-dependent, decreased by lipopolysaccharide (LPS)-induced MDDC maturation at higher particle concentrations, and was inhibited by cytochalasin D pre-treatment. PVA-SPIONs did not alter surface marker expression (CD80, CD83, CD86, myeloid/plasmacytoid DC markers) or antigen-uptake, but decreased the capacity of MDDCs to process antigen, stimulate CD4+ T cells, and induce cytokines. The decreased antigen processing and CD4+ T cell stimulation capability of MDDCs following PVA-SPION treatment suggests that MDDCs may revert to a more functionally immature state following particle exposure.

A [4.5.5.5]Fenestrene via intramolecular enone-alkyne photocycloaddition

Abstract A new entry into substituted [4.5.5.5]fenestrenes containing a bridgehead double bond and some its reactions are described.

Stereoselectivity in reactions of bicyclo[3.3.0]oct-1-enes

Abstract The derivatives of trans-bicyclo[3.3.0]octane 3 and 6 have been obtained the bicyclo[3.3.0]oct-1-enes, sterically hindered at the exo-side, via photoinduced [2+2]cycloaddition of 1 with ethylvinyl ether and by hydroboration-oxidation of 5d , respectively.