T-cell vaccines that elicit effective immune responses against HCV in chimpanzees may create greater immune pressure for viral mutation.

A prime/boost vaccine strategy that transfects antigen-presenting cells using ligand-modified immunoliposomes to efficiently deliver plasmid DNA, followed by boosting with non-replicating recombinant adenovirus was used in chimpanzees to generate HCV-specific memory T-cells. Three chimpanzees (two vaccines, one control) were immunized with immunoliposomes complexed with DNA expressing NS3-NS5B or complexed with empty vector. Animals were boosted with adenovirus expressing NS3-NS5B, or non-recombinant adenovirus (control).

Secretory antibodies reduce systemic antibody responses against the gastrointestinal commensal flora.

The humoral response to the gastrointestinal (GI) flora was analyzed in secretory Ig (sIg)-deficient polymeric IgR (pIgR)(-/-) mice and otherwise congenic C57BL/6 mice. While both strains carried an ileal flora of similar size and composition, increased bacterial translocation to mesenteric lymph node was demonstrated in pIgR(-/-) mice. Serum IgA was greatly increased in pIgR(-/-) mice compared with C57BL/6 mice and reacted with commensal organisms and food.

Hepatic precursors derived from murine embryonic stem cells contribute to regeneration of injured liver.

We established an efficient system for differentiation, expansion and isolation of hepatic progenitor cells from mouse embryonic stem (ES) cells and evaluated their capacity to repopulate injured liver. Using mouse ES cells transfected with the green fluorescent protein (GFP) reporter gene regulated by albumin (ALB) enhancer/promoter, we found that a serum-free chemically defined medium supports formation of embryoid bodies (EBs) and differentiation of hepatic lineage cells in the absence of exogenous growth factors or feeder cell layers. The first GFP+ cells expressing ALB were detected in close proximity to "beating" myocytes after 7 days of EB cultures.

Innate secretory antibodies protect against natural Salmonella typhimurium infection.

The production of IgA is induced in an antigen-unspecific manner by commensal flora. These secretory antibodies (SAbs) may bind multiple antigens and are thought to eliminate commensal bacteria and self-antigens to avoid systemic recognition. In this study, we addressed the role of "innate" SAbs, i.

Vaccine-induced protection against gastrointestinal bacterial infections in the absence of secretory antibodies.

Secretory IgA (SIgA) is widely held to be responsible for the defense of the mucosae against pathogenics and other potentially harmful agents. In this study, polymeric Ig receptor (pIgR) knockout mice, which lack secretory antibodies (SAb), were used to investigate the role of vaccine-elicited SAb in protection against gastrointestinal bacterial infections. An essential role for specific SAb in protection against Vibrio cholerae was evident from experiments showing that vaccinated pIgR(-/-) mice, but not vaccinated C57BL/6 mice, were susceptible to cholera toxin challenge.