Anti-Ace monoclonal antibody reduces Enterococcus faecalis aortic valve infection in a rat infective endocarditis model.

Ace (Adhesin to collagen from Enterococcus faecalis) is a cell-wall anchored protein that is expressed conditionally and is important for virulence in a rat infective endocarditis (IE) model. Previously, we showed that rats immunized with the collagen binding domain of Ace (domain A), or administered anti-Ace domain A polyclonal antibody, were less susceptible to E. faecalis endocarditis than sham-immunized controls.

Processing of the major autolysin of E. faecalis, AtlA, by the zinc-metalloprotease, GelE, impacts AtlA septal localization and cell separation.

AtlA is the major peptidoglycan hydrolase of Enterococcus faecalis involved in cell division and cellular autolysis. The secreted zinc metalloprotease, gelatinase (GelE), has been identified as an important regulator of cellular function through post-translational modification of protein substrates. AtlA is a known target of GelE, and their interplay has been proposed to regulate AtlA function.

Lymphatic delivery of etanercept via nanotopography improves response to collagen-induced arthritis.

Background: Evidence suggests lymphatic function mediates local rheumatoid arthritis (RA) flares. Yet biologics that target the immune system are dosed systemically via the subcutaneous (SC) administration route, thereby inefficiently reaching local lymphatic compartments. Nanotopography has previously been shown to disrupt tight cellular junctions, potentially enhancing local lymphatic delivery and potentially improving overall therapeutic efficacy.

Functional studies of E. faecalis RNase J2 and its role in virulence and fitness.

Post-transcriptional control provides bacterial pathogens a method by which they can rapidly adapt to environmental change. Dual exo- and endonucleolytic activities of RNase J enzymes contribute to Gram-positive RNA processing and decay. First discovered in Bacillus subtilis, RNase J1 plays a key role in mRNA maturation and degradation, while the function of the paralogue RNase J2 is largely unknown.

Antibody Guided Molecular Imaging of Infective Endocarditis.

In this protocol, we describe the application of using a high affinity monoclonal antibody generated against the major pilin protein component of the pilin structure of Enterococcus faecalis as a PET imaging agent for enterococcal endocarditis detection. The anti-pilin -mAb 64Cu conjugate was able to specifically label enterococcal endocarditis vegetation in vivo in a rodent endocarditis model. By targeting pili, a covalently linked surface antigen extending from the bacterial surface, we provided evidence that gram-positive pilin represent a logical surface antigen to define or target an infectious agent for molecularly guided imaging.

Comparison of DOTA and NODAGA as chelators for (64)Cu-labeled immunoconjugates.

Introduction: Bifunctional chelators have been shown to impact the biodistribution of monoclonal antibody (mAb)-based imaging agents. Recently, radiolabeled 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA)-peptide complexes have demonstrated improved in vivo stability and performance compared to their 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) counterparts. Here, we investigated if similar utility could be achieved with mAbs and compared (64)Cu-labeled DOTA and NODAGA-immunoconjugates for the detection of epithelial cell adhesion molecule (EpCAM) in a prostate cancer model.

Deglycosylation of mAb by EndoS for improved molecular imaging.

Purpose: Monoclonal antibodies (mAbs) have been shown preclinically as reliable targeting moieties for antigen imaging using near-infrared fluorescence (NIRF) molecular imaging. However, crystallizable fragment-gamma receptor (FcγRs) expressed on immune cells also bind mAbs through defined epitopes on the constant fragment (Fc) of IgG. Herein, we evaluate the potential impact Fc interactions have on mAb agent imaging specificity.

Targeting pili in enterococcal pathogenesis.

Passive protection, the administration of antibodies to prevent infection, has garnered significant interest in recent years as a potential prophylactic countermeasure to decrease the prevalence of hospital-acquired infections. Pili, polymerized protein structures covalently anchored to the peptidoglycan wall of many Gram-positive pathogens, are ideal targets for antibody intervention, given their importance in establishing infection and their accessibility to antibody interactions. In this work, we demonstrated that a monoclonal antibody to the major component of Enterococcus faecalis pili, EbpC, labels polymerized pilus structures, diminishes biofilm formation, and significantly prevents the establishment of a rat endocarditis infection.

Library screen identifies Enterococcus faecalis CcpA, the catabolite control protein A, as an effector of Ace, a collagen adhesion protein linked to virulence.

The Enterococcus faecalis cell wall-anchored protein Ace is an important virulence factor involved in cell adhesion and infection. Expression of Ace on the cell surface is affected by many factors, including stage of growth, culture temperature, and environmental components, such as serum, urine, and collagen. However, the mechanisms that regulate or modulate Ace display are not well understood.

Tumor margin detection using quantitative NIRF molecular imaging targeting EpCAM validated by far red gene reporter iRFP.

Purpose: Wide-field surgical excision reduces the chance of residual disease, but can also lead to disfigurement and devastating morbidities when resection is close to critical structures. We hypothesize that near-infrared fluorescence (NIRF) imaging can enable accurate detection of tumor margins for image-guided resection.

Experimental Design: An orthotopic model of human prostate cancer (PCa) was used to assess primary tumor margins using a NIRF-labeled antibody against epithelial cell adhesion molecule (EpCAM).

Comparison of mAbs targeting epithelial cell adhesion molecule for the detection of prostate cancer lymph node metastases with multimodal contrast agents: quantitative small-animal PET/CT and NIRF.

Unlabelled: The proliferation of most carcinomas is associated with an overexpression of epithelial cell adhesion molecule (EpCAM), a 40-kDa type I transmembrane protein found on epithelial cells yet absent from other cell types. The absence of EpCAM in normal lymphatics makes it an attractive marker for studying lymph node (LN) metastases of carcinomas to improve LN staging accuracy. Herein, we developed and quantitatively compared dual-labeled monoclonal antibodies (mAbs) of varying affinities against EpCAM for both noninvasive and intraoperative detection of metastatic LNs in prostate cancer.

The Fsr quorum-sensing system of Enterococcus faecalis modulates surface display of the collagen-binding MSCRAMM Ace through regulation of gelE.

Ace, a known virulence factor and the first identified microbial surface component recognizing adhesive matrix molecule (MSCRAMM) of Enterococcus faecalisis associated with host cell adherence and endocarditis. The Fsr quorum-sensing system of E. faecalis, a two-component signal transduction system, has also been repeatedly linked to virulence in E.

Enterococcus faecalis rnjB is required for pilin gene expression and biofilm formation.

Pili in Gram-positive bacteria play a major role in the colonization of host tissue and in the development of biofilms. They are promising candidates for vaccines or drug targets since they are highly immunogenic and share common structural and functional features among various Gram-positive pathogens. Numerous publications have helped build a detailed understanding of pilus surface assembly, yet regulation of pilin gene expression has not been well defined.