Synthesis and Electrochemistry of ((Diferrocenylsilyl)propyl)- and ((Triferrocenylsilyl)propyl)triethoxysilanes

Triferrocenylsilane <b>2</b> was synthesized. Hydrosilylation reactions employing allyltriethoxysilane and diferrocenylmethylsilane (<b>1</b>) and triferrocenylsilane (<b>2</b>) yielded new ferrocenyltriethoxysilane compounds functionalized with two (<b>3</b>) and three (<b>4</b>) interacting ferrocenyl units, respectively. Characterization of <b>2</b> and the ethoxysilane derivatives <b>3</b> and <b>4</b> by elemental analysis, ¹H, ¹³C­{¹H}, and ²⁹Si­{¹H} NMR spectroscopy, and mass spectrometry supports their assigned structures. The crystal structure of <b>2</b> has been determined by a single-crystal X-ray diffraction study. The redox activity of the ferrocenyl centers in <b>2</b>–<b>4</b> has been characterized by cyclic voltammetry and square wave voltammetry in dichloromethane containing [<i>n</i>-Bu₄N]­[PF₆] or [<i>n</i>-Bu₄N]­[B­(C₆F₅)₄] as electrolyte support. Voltammetric studies of <b>2</b>–<b>4</b> in solution exhibit the pattern of communicating ferrocenyl sites with two or three distinct, separated oxidation waves. Platinum oxide surfaces are covalently modified by redox-active <b>3</b> and <b>4</b>

Immunogenicity and T cell recognition in swine of foot-and-mouth disease virus polymerase 3D

Immunization of domestic pigs with a vaccinia virus (VV) recombinant expressing foot-and-mouth disease virus (FMDV) 3D protein conferred partial protection against challenge with infectious virus. The severity reduction of the clinical symptoms developed by the challenged animals occurred in the absence of significant levels of anti-3D circulating antibodies. This observation suggested that the partial protection observed was mediated by the induction of a 3D-specific cellular immune response. To gain information on the T cell recognition of FMDV 3D protein, we conducted in vitro proliferative assays using lymphocytes from outbred pigs experimentally infected with FMDV and 90 overlapping peptides spanning the complete 3D sequence. The use of pools of two to three peptides allowed the identification of T cell epitopes that were efficiently recognized by lymphocytes from at least four of the five animals analyzed. This recognition was heterotypic because anti-peptide responses increased upon reinfection of animals with a FMDV isolate from a different serotype. The results obtained with individual peptides confirmed the antigenicity observed with peptide pools. Detection of cytokine mRNAs by RT-PCR in lymphocytes stimulated in vitro by individual 3D peptides revealed that IFN-γ mRNA was the most consistently induced, suggesting that the activated T cells belong to the Th 1 subset. These results indicate that 3D protein contains epitopes that can be efficiently recognized by porcine T lymphocytes from different infected animals, both upon primary and secondary (heterotypic) FMDV infection. These epitopes can extend the repertoire of viral T cell epitopes to be included in subunit and synthetic FMD vaccines. © 2004 Elsevier Inc. All rights reserved