The presentation of exogenous protein antigens in a major histocompatibility complex class I–restricted fashion to CD8+ T cells is called cross-presentation. We demonstrate that cross-presentation of soluble viral antigens (derived from hepatitis C virus [HCV], hepatitis B virus [HBV], or human immunodeficiency virus) to specific CD8+ T cell clones is dramatically improved when antigen-presenting dendritic cells (DCs) are pulsed with the antigen in the presence of chloroquine or ammonium chloride, which reduce acidification of the endocytic system. The export of soluble antigen into the cytosol is considerably higher in chloroquine-treated than in untreated DCs, as detected by confocal microscopy of cultured cells and Western blot analysis comparing endocytic and cytosolic fractions. To pursue our findings in an in vivo setting, we boosted groups of HBV vaccine responder individuals with a further dose of hepatitis B envelope protein vaccine with or without a single dose of chloroquine. Although all individuals showed a boost in antibody titers to HBV, six of nine individuals who were administered chloroquine showed a substantial CD8+ T cell response to HBV antigen, whereas zero of eight without chloroquine lacked a CD8 response. Our results suggest that chloroquine treatment improves CD8 immunity during vaccination.

Shock wave treatment promoted cell growth and collagen synthesis of primary cultured human tenocytes. The clinical benefits of ESWT may be ascribed to an increased efficiency of tendon repair after injury.

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FGF-2, a potent angiogenic factor that is involved in tumor invasion, is known to be released extracellularly by a nonclassical secretory pathway. Recently it has become clear that Epstein-Barr virus, specifically its oncoprotein LMP1, can induce expression of angiogenic factors. Among these factors is FGF-2. LMP1 not only promotes expression of FGF-2, but also the release extracellularly of its 18-kDa isoform. We analyzed the mechanism of FGF-2 release induced by LMP1. Confocal immunofluorescence microscopy revealed colocalization of FGF-2 with LMP1 in small dots also stained positively for CD63 and cathepsin D, markers of late endosomes or multivesicular bodies. Biochemical analysis and immunoelectron microscopy of purified exosomal fractions from cotransfected cells demonstrated increased release of exosomes and the concentration of LMP1 and FGF-2 in these structures. Moreover, cotransfection appeared to induce partial redistribution of the Na 1 /K 1 -ATPase, which participates in FGF-2 release, from the plasma membrane to the intracellular LMP1/FGF-2 positive dots. Treatment with ouabain, which inhibits Na 1 /K 1 -ATPase activity, partially suppressed FGF-2 secretion via exosomes in a dose-dependent manner. The results suggest that exosomes may represent a previously unrecognized mechanism for FGF-2 release mediated by LMP1, and that this pathway involves the activity of Na 1 /K 1 -ATPase. ' 2007 Wiley-Liss, Inc.