Objective. Complement has both protective and pathogenic functions in lupus due to a balance between its role in the clearance of immune complexes (ICs) and apoptotic cells and its role in inflammation. The classical pathway contributes to IC and apoptotic cell clearance, whereas the alternative pathway is a key mediator of renal inflammation. The aim of this study was to investigate the effect of a new targeted inhibitor of the alternative pathway, CR2-fH, on lupus-like renal disease in MRL/lpr mice.Methods. Mice were treated with either saline, CR2-fH, CR2-Crry (which inhibits all complement pathways), or soluble CR2 (sCR2; C3d-binding targeting vehicle). Sera were analyzed every 2 weeks for autoantibodies, circulating ICs, and C3. Urinary excretion of albumin was also determined, and kidneys were collected at 23 weeks for histologic evaluation.Results. Treatment with CR2-fH or CR2-Crry improved survival and significantly reduced proteinuria, glomerular C3 deposition, and the level of circulating ICs. CR2-fH, but not CR2-Crry, also significantly reduced glomerulonephritis, expression of serum antidouble-stranded DNA (anti-dsDNA) antibodies, and glomerular IgG and C1q deposition. Interestingly, sCR2 also significantly reduced the levels of anti-dsDNA antibodies and circulating ICs and reduced glomerular deposition of IgG, C1q, and C3, although there was no significant reduction in glomerulonephritis, proteinuria, or mortality.Conclusion. Targeted and selective inhibition of the alternative complement pathway is an effective treatment of murine lupus and is more effective than blockade of all pathways. The data demonstrate benefits to leaving the classical/lectin pathways intact and indicate distinct roles for the classical and alternative pathways of complement in disease progression. The sCR2-targeting vehicle contributes to therapeutic activity, possibly via modulation of autoimmunity.The complement system can be activated by 1 of 3 pathways (classical, lectin, and alternative) and provides important host defense, homeostasis, and immune regulatory functions. However, the complement system also plays a pathogenic role in many autoimmune and inflammatory diseases, including systemic lupus erythematosus (SLE) (1). SLE is the prototypic human autoimmune disease, and complement-mediated injury is initiated by immune complexes (ICs) formed by autoantibodies directed against a broad range of self antigens (2,3). The kidney is a major site of immune complex formation and/or deposition, and lupus nephritis is a major cause of morbidity and mortality, in both human SLE and murine models of lupus. There is, however, an apparent dual role for complement in the development and progression of lupus, as highlighted by the different roles of the classical and alternative complement pathways in the disease.Patients with homozygous deficiencies of early Supported by grants from the US Department of Defense (W81 XWH-07-1-0161) and the NIH (HL-082485).

Clinically, the pharmacological effect of CSA is quantifiable, and lies in the upper end of the predicted range. In our Neoral-treated sample population, Cmax was associated with the least variable "cyclosporine effect." Such information could potentially individualize immunosuppression, and lead to rational dosing strategies.

defective in the production of both reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI), were used to investigate the role of phagocytic cells during mucosal and systemic candidiasis of endogenous origin. The alimentary tracts of germfree mice were colonized with Candida albicans wild type or each of two hyphal signaling-defective mutants (efg1/efg1 and efg1/efg1 cph1/cph1). All Candida-colonized gp91 phox؊/؊ /NOS2 ؊/؊ mice were moribund within 12 to 15 days after oral inoculation. C. albicans wild-type and mutant strains colonized the alimentary tracts equally well and were able to translocate, most likely via Peyer's patches and mesenteric lymph nodes, to the internal organs and trigger the formation of abscesses; however, the wild-type and mutant strains did not survive in the abscessed murine tissues. Surprisingly, there was no significant difference in the ability of peritoneal exudate cells from gp91 phox؊/؊ /NOS2 ؊/؊ , NOS2 ؊/؊ , gp91 phox؊/؊ , or immunocompetent C57BL/6 mice to kill C. albicans in vitro. This suggests that anti-Candida factors other than ROI and RNI can control the growth of C. albicans and that gp91 phox؊/؊ /NOS2 ؊/؊ mice die due to the inability of the host to control its inflammatory response to Candida. Correspondingly, reverse transcription-PCR analysis showed increased expression of the cytokines gamma interferon, tumor necrosis factor alpha, and the chemokines MIP-2 and KC at the site of infection, while interleukin-15 expression remained relatively unchanged between germfree and infected tissues. These studies indicate that defects in ROI and RNI enabled C. albicans to translocate and disseminate to the internal organs, resulting in an uncontrolled immune response, severe pathology, and death; however, ROI and RNI were not required for the killing of phagocytized C. albicans, indicating that other anti-Candida factors either compensate or are sufficient for the killing of phagocytized Candida.

To investigate whether host immunocompetence influences hydrolytic gene expression, we compared secretory aspartyl proteinase gene (SAP) and phospholipase B gene (PLB) expression during gastric candidiasis in immunocompetent and defined immunodeficient gnotobiotic mice, by reverse-transcription polymerase chain reaction. The use of immunodeficient gnotobiotic mice with combined defects in T cells and natural killer cells enabled a comprehensive study of virulence gene expression in various mucosal sites during lethal oroesophageal (tongue, palate, and esophagus) and gastric candidiasis. All 10 SAP and both PLB genes were expressed in both immunocompetent and specific immunodeficient mice, which suggests that the absence of important components of the host defense did not alter gene expression during gastric candidiasis. Although similar patterns of gene expression were evident in different oral tissues, we detected specific differences between Candida albicans-infected oroesophageal and gastric tissues and differences at various time points during the progression of gastric candidiasis.

No abstract