Appropriately simulating the three-dimensional (3D) environment in which tissues normally develop and function is crucial for engineering in vitro models that can be used for the meaningful dissection of host-pathogen interactions. This Review highlights how the rotating wall vessel bioreactor has been used to establish 3D hierarchical models that range in complexity from a single cell type to multicellular co-culture models that recapitulate the 3D architecture of tissues observed in vivo. The application of these models to the study of infectious diseases is discussed.
Noroviruses (NoV) cause the great majority of epidemic nonbacterial gastroenteritis in humans. Expression of the capsid protein in recombinant systems, including insect and plant cells, yields assembly of virus-like particles (VLPs) that mimic the antigenic structure of authentic virions, and are relatively acid- and heat-stable. Norwalk virus (NV), the prototype NoV, has been studied extensively, and Norwalk virus-like particles (NVLPs) produced in insect cells and plants are immunogenic in mice and humans when delivered orally, stimulating the production of systemic and mucosal anti-NV antibodies. NVLPs are also highly immunogenic when delivered intranasally, provoking antibodies at levels similar to orally delivered VLP at much lower doses. Oral and nasal delivery of NVLPs efficiently produces antibodies at distal mucosal sites, which suggests that NVLPs could be used to deliver heterologous peptide antigens by production of genetic fusion chimeric capsid proteins. Examination of norovirus VLP surface structures and receptor binding motifs facilitates identification of potential sites for insertion of foreign peptides that will minimally affect the efficiency of VLP assembly and receptor binding. Thus, there is strong potential to use norovirus VLPs as vaccine-delivery vehicles.
For over a century it has been well documented that bacteria in the vagina maintain vaginal homeostasis, and that an imbalance or dysbiosis may be associated with poor reproductive and gynecologic health outcomes. Vaginal microbiota are of particular significance to postmenopausal women and may have a profound effect on vulvovaginal atrophy, vaginal dryness, sexual health and overall quality of life. As molecular-based techniques have evolved, our understanding of the diversity and complexity of this bacterial community has expanded. The objective of this review is to compare the changes that have been identified in the vaginal microbiota of menopausal women, outline alterations in the microbiome associated with specific menopausal symptoms, and define how hormone replacement therapy impacts the vaginal microbiome and menopausal symptoms; it concludes by considering the potential of probiotics to reinstate vaginal homeostasis following menopause. This review details the studies that support the role of Lactobacillus species in maintaining vaginal homeostasis and how the vaginal microbiome structure in postmenopausal women changes with decreasing levels of circulating estrogen. In addition, the associated transformations in the microanatomical features of the vaginal epithelium that can lead to vaginal symptoms associated with menopause are described. Furthermore, hormone replacement therapy directly influences the dominance of Lactobacillus in the microbiota and can resolve vaginal symptoms. Oral and vaginal probiotics hold great promise and initial studies complement the findings of previous research efforts concerning menopause and the vaginal microbiome; however, additional trials are required to determine the efficacy of bacterial therapeutics to modulate or restore vaginal homeostasis.