Focal segmental glomerulosclerosis (FSGS) is a cause of proteinuric kidney disease, compromising both native and transplanted kidneys. Treatment is limited because of a complex pathogenesis, including unknown serum factors. Here we report that serum soluble urokinase receptor (suPAR) is elevated in two-thirds of subjects with primary FSGS, but not in people with other glomerular diseases. We further find that a higher concentration of suPAR before transplantation underlies an increased risk for recurrence of FSGS after transplantation. Using three mouse models, we explore the effects of suPAR on kidney function and morphology. We show that circulating suPAR activates podocyte β3 integrin in both native and grafted kidneys, causing foot process effacement, proteinuria and FSGS-like glomerulopathy. Our findings suggest that the renal disease only develops when suPAR sufficiently activates podocyte β3 integrin. Thus, the disease can be abrogated by lowering serum suPAR concentrations through plasmapheresis, or by interfering with the suPAR–β3 integrin interaction through antibodies and small molecules targeting either uPAR or β3 integrin. Our study identifies serum suPAR as a circulating factor that may cause FSGS.

Human cytomegalovirus (CMV) is a viral pathogen that infects both genders, who remain asymptomatic unless they receive immunosuppressive drugs or acquire infections that cause reactivation of latent virus. CMV infection also causes serious birth defects following primary maternal infection during gestation. A safe and effective vaccine to limit disease in this population continues to be elusive. A well-studied antigen is glycoprotein B (gB), which is the principal target of neutralizing antibodies (NAb) towards CMV in humans and has been implicated as the viral partner in the receptor-mediated infection by CMV in a variety of cell types. Antibody-mediated virus neutralization has been proposed as a mechanism by which host immunity could modify primary infection. Towards this goal, an attenuated poxvirus, modified vaccinia virus Ankara (MVA), has been constructed to express soluble CMV gB (gB680-MVA) to induce CMV NAb. Very high levels of gB-specific CMV NAb were produced after two doses of the viral vaccine. NAb were durable within a twofold range for up to 6 months. Neutralization titers developed in immunized mice are equivalent to titers found clinically after natural infection. This viral vaccine, expressing gB derived from CMV strain AD169, induced antibodies that neutralized CMV strains of three different genotypes. Remarkably, preexisting MVA and vaccinia virus (poxvirus) immunity did not interfere with subsequent immunizations of gB680-MVA. The safety characteristics of MVA, combined with the robust immune response to CMV gB, suggest that this approach could be rapidly translated into the clinic.Human cytomegalovirus (HCMV) is a member of the herpesvirus family. It is a major cause of congenital disease, resulting in an estimated 4,000 cases of symptomatic congenital cytomegalovirus (CMV) infection per year in the United States (58). An effective CMV vaccine that can prevent or reduce CMV-associated disease is highly desirable. Early studies have indicated that HCMV gB is the major target of NAb that are induced by naturally acquired CMV infection (16,39). It is the most highly conserved envelope glycoprotein of human herpesviruses (38). Thus, CMV gB has been an attractive candidate for CMV vaccine development. CMV gB vaccines using recombinant gB protein expressed from plasmid DNA and gB expressed in several different viral vectors (ALVAC, adenovirus, and vaccinia virus [VV]) have been investigated with animal models (9,13,23,26,31,40,54). Safety and moderate immunogenicity have been demonstrated with these vaccines, but no licensed CMV vaccine is available. A live attenuated Towne strain of CMV, either alone or with a gB subunit vaccine as a prime-boost, have also been evaluated in human subjects (1, 2, 48).Full-length CMV gB is synthesized as a 907-amino acid (aa) precursor in CMV-infected cells with a predicted molecular mass of 105 kDa, but it can be glycosylated to form a 170-kDa modified protein (17). To enable pharmaceutical development, truncated and secretable forms of gB were derived. These in...

Inhibiting human immunodeficiency virus (HIV) replication with potent antiretroviral therapy may result in improved immune function, and this may lead to favorable outcomes, independent of changes in CD4+ lymphocyte count. The effect of combination protease inhibitor therapy (ritonavir plus saquinavir) on functional measures of cell-mediated immunity in 41 HIV-infected patients from one center of a multicenter trial was investigated. After 24 weeks, median plasma virus load decreased from 4.74 log10 copies/mL to below the detection limit of the assay (2.30 log10), and mean CD4+ lymphocyte count increased from 284 cells/microL to 413 cells/microL. Proliferative responses to phytohemagglutinin developed in 21 of 34 patients in whom responses were absent at baseline. Increases were observed in interleukin-2, -12, and -10 production and in the expression of CD28 on CD8+ lymphocytes. Initiation of potent anti-HIV therapy results in a degree of immune restoration, suggesting that HIV-induced immune suppression is a dynamic and potentially reversible process.

DNA-based vaccines hold promise to outperform conventional antigen-based vaccines by virtue of many unique features. However, DNA vaccines have thus far fallen short of expectations, due in part to poor targeting of professional antigen-presenting cells (APC) and low immunogenicity. In this study, we describe a new platform for effective and selective delivery of DNA to APCs in vivo that offers intrinsic immuneenhancing characteristics. This platform is based on conjugation of fifth generation polyamidoamine (G5-PAMAM) dendrimers, a DNA-loading surface, with MHC class II-targeting peptides that can selectively deliver these dendrimers to APCs under conditions that enhance their immune stimulatory potency. DNA conjugated with this platform efficiently transfected murine and human APCs in vitro. Subcutaneous administration of DNA-peptide-dendrimer complexes in vivo preferentially transfected dendritic cells (DC) in the draining lymph nodes, promoted generation of high affinity T cells, and elicited rejection of established tumors. Taken together, our findings show how PAMAM dendrimer complexes can be used for high transfection efficiency and effective targeting of APCs in vivo, conferring properties essential to generate effective DNA vaccines. Cancer Res; 71(24); 7452-62. Ó2011 AACR.