Complement receptor 2–mediated targeting of complement inhibitors to sites of complement activation

Song, Hwangjun; He, Chu; Knaak, Christian; Guthridge, Joel M.; Holers, V. Michael; Tomlinson, Stephen

doi:10.1172/jci200317348

Cited by 28 publications

(32 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Plasmid constructs encoding each component of the fusion protein were also prepared, i.e., mouse CR2(SCR1–4) and mouse fH(SCR1–5). All constructs were prepared by standard PCR methods and were cloned into the previously described PBM vector with a CD5 signal peptide sequence for expression (16). Construction of the expression plasmid for CR2-Crry has been described previously (11).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A Novel Targeted Inhibitor of the Alternative Pathway of Complement and Its Therapeutic Application in Ischemia/Reperfusion Injury

Huang

Qiao

Atkinson

et al. 2008

The Journal of Immunology

Self Cite

120

176

View full text Add to dashboard Cite

Bioavailability and therapeutic efficacy of soluble Crry, a mouse inhibitor of all complement activation pathways, is significantly enhanced when linked to a fragment of complement receptor 2 (CR2), a receptor that targets C3 activation products. In this study, we characterize alternative pathway-specific inhibitors consisting of a single or dimeric N-terminal region of mouse factor H (fH; short consensus repeats 1–5) linked to the same CR2 fragment (CR2-fH and CR2-fHfH). Both CR2-fH and CR2-fHfH were highly effective at inhibiting the alternative pathway in vitro and demonstrated a higher specific activity than CR2-Crry. CR2-fH was also more effective than endogenous serum fH in blocking target deposition of C3. Target binding and complement inhibitory activity of CR2-fH/CR2-fHfH was dependent on CR2- and C3-mediated interactions. The alternative pathway of complement plays a role in intestine ischemia/reperfusion injury. However, serum fH fails to provide protection against intestine ischemia/reperfusion injury although it can bind to and provide cell surfaces with protection from complement and is present in plasma at a high concentration. In a mouse model, CR2-fH and CR2-fHfH provided complete protection from local (intestine) and remote (lung) injury. CR2-fH targeted to the site of local injury and greatly reduced levels of tissue C3 deposition. Thus, the targeting mechanism significantly enhances alternative pathway-specific complement inhibitory activity of the N-terminal domain of fH and has the potential to reduce side effects that may be associated with systemic complement blockade. The data further indicate alternative pathway dependence for local and remote injury following intestinal ischemia/reperfusion in a clinically relevant therapeutic paradigm.

show abstract

Section: Methodsmentioning

confidence: 99%

“…Expression plasmids were transfected into Chinese hamster ovary (CHO) cells with FuGene-HD transfection reagent according to the manufacturer's instructions (Roche Applied Science). Positive clones were selected by limiting dilution as previously described (16) and protein expression was quantified by ELISA and dot blot.…”

Section: Methodsmentioning

confidence: 99%

A Novel Targeted Inhibitor of the Alternative Pathway of Complement and Its Therapeutic Application in Ischemia/Reperfusion Injury

Huang

Qiao

Atkinson

et al. 2008

The Journal of Immunology

Self Cite

120

176

View full text Add to dashboard Cite

show abstract

“…All incubations and washes were performed in DMEM. Complement-mediated lysis of sensitized CHO cells was determined in the presence or absence of recombinant complement inhibitors by trypan blue exclusion as previously described (37). In these assays, 15% (final concentration) rat serum was used as complement source, which resulted in approximately 90% lysis of unprotected CHO cells.…”

Section: Figure 10mentioning

confidence: 99%

“…We recently described a strategy to specifically target complement inhibitors to sites of complement activation by linking human complement inhibitors to the C3-binding region of human com-plement receptor 2 (CR2) (37). CR2 is a member of the C3-binding protein family and is expressed predominantly on mature B cells and follicular dendritic cells (38,39).…”

Section: Introductionmentioning

confidence: 99%

“…Natural ligands for the CR2-targeting moiety are iC3b, C3dg, and C3d, cell-bound cleavage fragments of C3 that are present at sites of complement activation (40,41). In vitro studies have shown that CR2-targeted complement inhibitors bind to C3-opsonized cells and are more effective than untargeted complement inhibitors at protecting target cells from complement deposition and lysis (37).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Targeted complement inhibition by C3d recognition ameliorates tissue injury without apparent increase in susceptibility to infection

Atkinson

Song²,

Lü³

et al. 2005

Journal of Clinical Investigation

162

248

View full text Add to dashboard Cite

Previous studies indicate a pivotal role for complement in mediating both local and remote injury following ischemia and reperfusion of the intestine. Here, we report on the use of a mouse model of intestinal ischemia/ reperfusion injury to investigate the strategy of targeting complement inhibition to sites of complement activation by linking an iC3b/C3dg-binding fragment of mouse complement receptor 2 (CR2) to a mouse complement-inhibitory protein, Crry. We show that the novel CR2-Crry fusion protein targets sites of local and remote (lung) complement activation following intestinal ischemia and reperfusion injury and that CR2-Crry requires a 10-fold lower dose than its systemic counterpart, Crry-Ig, to provide equivalent protection from both local and remote injury. CR2-Crry has a significantly shorter serum half-life than Crry-Ig and, unlike Crry-Ig, had no significant effect on serum complement activity at minimum effective therapeutic doses. Furthermore, the minimum effective dose of Crry-Ig significantly enhanced susceptibility to infection in a mouse model of acute septic peritonitis, whereas the effect of CR2-Crry on susceptibility to infection was indistinguishable from that of PBS control. Thus, compared with systemic inhibition, CR2-mediated targeting of a complement inhibitor of activation improved bioavailability, significantly enhanced efficacy, and maintained host resistance to infection. IntroductionIntestinal ischemia/reperfusion injury (IRI) is a major complication associated with abdominal surgery, cardiopulmonary bypass, ruptured abdominal aneurysm, and cardiac arrest (1-5). Reduction of abdominal blood flow as a result of hemorrhagic shock also causes intestinal IRI, which commonly leads to bacterial translocation and sepsis. Intestinal IRI causes gut dysfunction that is characterized by impaired gut motility, increased intestinal permeability, and mucosal wall injury, all of which are thought to be mediated at least in part by complement activation and the infiltration of neutrophils (6-8). Complement activation products and tissue injury result in the induction of a systemic inflammatory response with the release of cytokines and chemokines, the upregulation of adhesion molecules, and the activation of leukocytes. The activation of a systemic proinflammatory state results in remote organ damage to which the lung is particularly susceptible (9-12).Many studies have utilized rodent models of intestinal IRI to investigate the underlying pathophysiological mechanisms of IRI and to test potential therapeutic strategies. The pathogenesis of IRI is complex, but a series of elegant studies have shown that preexisting clonally specific IgM antibodies bind to neoantigens exposed by the ischemic insult and, following reperfusion, activate

show abstract

Cappuccino mutation in an autoimmune‐prone strain of mice suggests a role of platelet function in the progression of immune complex crescentic glomerulonephritis

Yoshida¹,

Saiga²,

Hato³

et al. 2006

Arthritis & Rheumatism

View full text Add to dashboard Cite

Objective. Crescent formation in the renal glomerulus is a typical manifestation of progressive glomerulopathy associated with fatal renal failure; therefore, its prevention is of clinical importance. Little is known about the pathogenic mechanism for crescent formation. This study was undertaken in an attempt to identify the events that are critical for crescent formation in immune complex crescentic glomerulonephritis (CGN) by analyzing a novel mutant strain of mice.Methods. A spontaneous mutant strain of mice was isolated from the autoimmune-prone strain EOD, which stably develops fatal CGN. The mutant phenotypes were assessed histopathologically, hematologically, and immunologically. The mutation was searched for with positional cloning using microsatellite markers.Results. Compared with wild-type EOD (WT-EOD) mice, mutant EOD (mut-EOD) mice showed marked improvement in CGN in conjunction with an improvement in spontaneous mortality. In WT-EOD mice, an inverse correlation between blood urea nitrogen concentration and blood platelet count and massive accumulation of platelets in the glomerulus were evident, suggesting that an accumulation of platelets in the glomerulus contributes to the progression of CGN. The mutant platelets showed an abnormal aggregation in response to collagen and thrombin, associated with a bleeding tendency in mut-EOD mice. Genetic analysis revealed a deleterious mutation in the cappuccino gene (cno), which encodes a protein that belongs to a complex called the biogenesis of lysosome-related organelle complex 1 and is profoundly involved in platelet function. Morphologic examination revealed a partial defect in dense body formation in the ␦-granule of platelets.Conclusion. The present findings suggest that platelet functions have a critical role in crescent formation in autoimmune GN.In systemic autoimmune disease, renal function is frequently impaired due to immune-mediated inflammation. An example is the occurrence of lupus nephritis in association with systemic lupus erythematosus (SLE). Immune complex (IC) deposition is detected in the affected glomeruli of patients with lupus nephritis, thus suggesting a pathogenic role of ICs in this manifestation. Animal models have further demonstrated the indispensable roles of some receptors such as the Fc receptor for IgG (Fc␥R) (1,2) and complement receptors (CRs) (3,4), proinflammatory factors such as cytokines and chemokines, and growth factors in the progression of glomerulonephritis (GN) following IC deposition. These findings readily confirm the existence of a longstanding pathogenic mechanism through which IC deposition initiates an inflammatory cascade by engaging Fc␥R and CRs and liberates a range of proinflammatory factors.

show abstract

Complement receptor 2–mediated targeting of complement inhibitors to sites of complement activation

Cited by 28 publications

References 42 publications

A Novel Targeted Inhibitor of the Alternative Pathway of Complement and Its Therapeutic Application in Ischemia/Reperfusion Injury

A Novel Targeted Inhibitor of the Alternative Pathway of Complement and Its Therapeutic Application in Ischemia/Reperfusion Injury

Targeted complement inhibition by C3d recognition ameliorates tissue injury without apparent increase in susceptibility to infection

Cappuccino mutation in an autoimmune‐prone strain of mice suggests a role of platelet function in the progression of immune complex crescentic glomerulonephritis

Contact Info

Product

Resources

About