T-cell-biased immune responses generated by a mucosally targeted adenovirus-σ1 vaccine.

As most pathogens enter through the mucosa, it is important to develop vaccines that induce mucosal immunity. To this end, we generated a novel adenovirus (Ad) vaccine that displays the σ1 protein from reovirus to target junctional adhesion molecule 1 and sialic acid. Replication-defective Ad5 vectors were modified by replacement of the Ad fiber protein with σ1 (T3Dσ1) protein of reovirus T3D in previous work. Ad5 and Ad5-σ1 were compared in mouse models for gene delivery and vaccination to monitor cytokine, antibody, and T-cell responses. The viruses were also tested for the ability to transduce and mature dendritic cells. Ad5-σ1 was 40-fold less efficient at gene delivery in vivo, yet it was capable of inducing equal or greater cellular immune responses and systemic interferon-γ levels than Ad5 after intranasal administration. Despite weaker gross transduction, intranasal administration of Ad5-σ1 produced more green fluorescent protein-positive (GFP+) major histocompatibility complex class II (MHC II) cells in the draining lymph nodes, less GFP+/MHC II+ cells in the lungs, and mediated modestly better maturation of dendritic cells in vitro. These data suggest that targeting gene-based vaccination via the σ1 protein may enhance the T-cell immune response, perhaps by skewing immune responses to encoded antigens.

Nonlinear dielectric spectroscopy for label-free detection of respiratory activity in whole cells.

We report on a novel electromagnetic biosensing technique for detecting respiratory activity in whole cells suspended in aqueous solution. Application of a pure sinusoidal voltage between two outer electrodes applies an oscillatory electric field to the aqueous cell suspension at frequencies in the range of one to several kHz. The fundamental and higher order harmonic responses are measured across two inner electrodes using a dynamic signal analyzer. Aqueous suspensions of S. cerevisiae (budding yeast), with both active and inactive mitochondrial electron transport (respiratory) chains are employed for this study. We find that the measured third harmonic for certain frequency ranges shows significant temporal changes in actively respiring yeast, while little significant changes are observed in yeast with suppressed respiratory activity, i.e. mutant yeast strains or yeast in the presence of respiratory inhibitors. The method holds potential for further development to detect respiratory activity in live tissue in vitro and perhaps in vivo for clinical applications.