Stable Expression of Lentiviral Antigens by Quality-Controlled Recombinant Mycobacterium bovis BCG Vectors.

The well-established safety profile of the tuberculosis vaccine strain, Mycobacterium bovis bacille Calmette-Guérin (BCG), makes it an attractive vehicle for heterologous expression of antigens from clinically relevant pathogens. However, successful generation of recombinant BCG strains possessing consistent insert expression has encountered challenges in stability. Here, we describe a method for the development of large recombinant BCG accession lots which stably express the lentiviral antigens, human immunodeficiency virus (HIV) gp120 and simian immunodeficiency virus (SIV) Gag, using selectable leucine auxotrophic complementation.

Reconstructing mandibular defects using autologous tissue-engineered tooth and bone constructs.

Purpose: Current strategies for jaw reconstruction require multiple operations to replace bone and teeth. To improve on these methods, we investigated simultaneous mandibular and tooth reconstruction, using a Yucatan minipig model.

Materials And Methods: Tooth and bone constructs were prepared from third molar tooth tissue and iliac-crest bone marrow-derived osteoblasts isolated from, and implanted back into, the same pig as an autologous reconstruction.

Accurately shaped tooth bud cell-derived mineralized tissue formation on silk scaffolds.

Based on the successful use of silk scaffolds in bone tissue engineering, we examined their utility for mineralized dental tissue engineering. Four types of hexafluoroisopropanol (HFIP) silk scaffolds-(250 and 550 microm diameter pores, with or without arginine-glycine-aspartic acid (RGD) peptide) were seeded with cultured 4-day postnatal rat tooth bud cells and grown in the rat omentum for 20 weeks. Analyses of harvested implants revealed the formation of bioengineered mineralized tissue that was most robust in 550 microm pore RGD-containing scaffolds and least robust in 250 microm pore sized scaffolds without RGD.

Tissue-engineered hybrid tooth and bone.

Tooth loss accompanied by alveolar bone resorption presents a significant clinical problem. We have investigated the utility of a tissue-engineering approach to provide corrective therapies for tooth-bone loss. Hybrid tooth-bone tissues were bioengineered as follows.

The specificity of phenotypic induction of mouse and human stem cells by signaling complexes.

Controlling the specific differentiation of stem cells (SCs) is a goal sought by many because of the benefits it would yield for repair or replacement of damaged tissues and organs. We report the discovery of signaling complexes and describe their use in predictably guiding the differentiation of mouse and human SCs. The signaling complexes (Signal-plexes [S-ps]) induce mouse and human SCs to express specific phenotypes.