Detection of RSV F-specific human mucosal IgA antibody titers utilizing a sensitive electrochemiluminescence platform (67.8)

Abstract It has been previously shown that mucosal immune responses play a significant role in mediating protection against respiratory viral infections. Respiratory Syncytial Virus (RSV) is a persistent respiratory virus which infects humans throughout life and can cause severe lower respiratory tract infections, particularly in the elderly. Establishing key biomarkers of vaccine-induced immune response is essential to the development of a successful vaccine. In this study, thirty healthy human donors separated into two age cohorts were evaluated: Young Adult (20 to 30 yrs, n=10) and Elderly (65 to 85 yrs, n=20). Plasma samples from the 30 donors were evaluated for neutralizing antibody titers against wild-type (wt) RSV A2 using a micro-neutralization assay and results showed an average titer of ~10.5+2.2 log2 in both age cohorts. In an effort to investigate additional biomarkers, we evaluated nasal wash samples from these donors for wt RSV A2 and RSV-F specific IgA antibody titers. We utilized both a conventional ELISA and a novel Electrochemiluminescence technology to detect the antigen-specific IgA titers. Results from these studies identified the Electrochemiluminescence platform as being a highly sensitive and powerful technology with a wide enough dynamic range to discern subtle differences in mucosal IgA antibody titers. Utilizing such an approach to detect critical biomarkers in dilute nasal wash samples should benefit clinical vaccine development.</jats:p

Variations in aggrecan structure modulate its susceptibility to aggrecanases.

Proteoglycan aggregates and purified aggrecan from adult and fetal bovine cartilage and adult and neonatal human cartilage were subjected to in vitro degradation by recombinant aggrecanase-1 and aggrecanase-2. The ability of the aggrecanases to cleave within the aggrecan IGD (interglobular domain) and CS2 domain (chondroitin sulphate-rich domain 2) was monitored by SDS/PAGE and immunoblotting. Aggrecanase-2 showed a similar ability to cleave within the IGD of adult and immature aggrecan, whereas aggrecanase-1 was less efficient in cleavage in the IGD of immature aggrecan, for both the bovine and the human substrates. Both aggrecanases showed a similar ability to cleave within the CS2 domain of bovine aggrecan irrespective of age, but showed a much lower ability to cleave within the CS2 domain of human aggrecan. Equivalent results were obtained whether aggrecan was present in isolation or as part of proteoglycan aggregates. When proteoglycan aggregates were used, neither aggrecanase was able to cleave link protein. Thus, for aggrecan cleavage by aggrecanases, variations in cleavage efficiency exist with respect to the species and age of the animal from which the aggrecan is derived and the type of aggrecanase being used

Aggrecanolysis and in vitro matrix degradation in the immature bovine meniscus: mechanisms and functional implications

INTRODUCTION: Little is known about endogenous or cytokine-stimulated aggrecan catabolism in the meniscal fibrocartilage of the knee. The objectives of this study were to characterize the structure, distribution, and processing of aggrecan in menisci from immature bovines, and to identify mechanisms of extracellular matrix degradation that lead to changes in the mechanical properties of meniscal fibrocartilage. METHODS: Aggrecanase activity in the native immature bovine meniscus was examined by immunolocalization of the aggrecan NITEGE neoepitope. To investigate mechanisms of cytokine-induced aggrecan catabolism in this tissue, explants were treated with interleukin-1α (IL-1) in the absence or presence of selective or broad spectrum metalloproteinase inhibitors. The sulfated glycosaminoglycan (sGAG) and collagen contents of explants and culture media were quantified by biochemical methods, and aggrecan catabolism was examined by Western analysis of aggrecan fragments. The mechanical properties of explants were determined by dynamic compression and shear tests. RESULTS: The aggrecanase-generated NITEGE neoepitope was preferentially localized in the middle and outer regions of freshly isolated immature bovine menisci, where sGAG density was lowest and blood vessels were present. In vitro treatment of explants with IL-1 triggered the accumulation of NITEGE in the inner and middle regions. Middle region explants stimulated with IL-1 exhibited substantial decreases in sGAG content, collagen content, and mechanical properties. A broad spectrum metalloproteinase inhibitor significantly reduced sGAG loss, abrogated collagen degradation, and preserved tissue mechanical properties. In contrast, an inhibitor selective for ADAMTS-4 and ADAMTS-5 was least effective at blocking IL-1-induced matrix catabolism and loss of mechanical properties. CONCLUSIONS: Aggrecanase-mediated aggrecanolysis, typical of degenerative articular cartilage, may play a physiologic role in the development of the immature bovine meniscus. IL-1-induced release of sGAG and loss of mechanical properties can be ascribed primarily to the activity of MMPs or aggrecanases other than ADAMTS-4 and ADAMTS-5. These results may have implications for the clinical management of osteoarthritis

Development of a High-Throughput Respiratory Syncytial Virus Fluorescent Focus-Based Microneutralization Assay

ABSTRACT Neutralizing antibodies specific for respiratory syncytial virus (RSV) represent a major protective mechanism against RSV infection, as demonstrated by the efficacy of the immune-prophylactic monoclonal antibody palivizumab in preventing RSV-associated lower respiratory tract infections in premature infants. Accordingly, the RSV neutralization assay has become a key functional method to assess the neutralizing activity of serum antibodies in preclinical animal models, epidemiology studies, and clinical trials. In this study, we qualified a 24-h, fluorescent focus-based microneutralization (RSVA FFA-MN) method that requires no medium exchange or pre- or postinfection processing to detect green fluorescent protein-expressing RSV strain A2 (RSVA-GFP)-infected cells, using a high-content imaging system for automated image acquisition and focus enumeration. The RSVA FFA-MN method was shown to be sensitive, with a limit of detection (LOD) and limit of quantitation (LOQ) of 1:10, or 3.32 log 2 ; linear over a range of 4.27 to 9.65 log 2 50% inhibitory concentration (IC 50 ); and precise, with intra- and interassay coefficients of variation of &lt;21%. This precision allowed the choice of a statistically justified 3-fold-rise seroresponse cutoff criterion. The repeatability and robustness of this method were demonstrated by including a pooled human serum sample in every assay as a positive control (PC). Over 3 years of testing between two laboratories, this PC generated data falling within 2.5 standard deviations of the mean 98.7% of the time ( n = 1,720). This high-throughput and reliable RSV microneutralization assay has proven useful for testing sera from preclinical vaccine candidate evaluation studies, epidemiology studies, and both pediatric and adult vaccine clinical trials. </jats:p

DEVELOPMENT OF AN IMPROVED EPSTEIN-BARR VIRUS (EBV) NEUTRALIZING ANTIBODY ASSAY TO FACILITATE DEVELOPMENT OF A PROPHYLACTIC GP350-SUBUNIT EBV VACCINE

No licensed vaccine is available for prevention of EBV-associated diseases, and robust, sensitive, and high-throughput bioanalytical assays are needed to evaluate immunogenicity of gp350 subunit-based candidate EBV vaccines. Here we have developed and improved analytical tools for such a vaccine’s pre-clinical and clinical validation including a gp350-specific antibody detection assay and an EBV-GFP based neutralization assay for measuring EBV specific antibodies in human donors. The sensitivity of our previously published high-throughput EBV-GFP fluorescent focus (FFA)-based neutralization assay was further improved when guinea pig complement was supplemented using a panel of healthy human sera. Anti-gp350 antibody titers, which were evaluated using an anti-gp350 IgG ELISA assay optimized for capture and detection conditions, were moderately correlated to the FFA-based neutralization titers. Overall, these sensitive, and high-throughput bioanalytical assays are capable of characterizing the serologic response to natural EBV infection, with applications in evaluating EBV antibody status in epidemiologic studies and immunogenicity of candidate gp350-subunit EBV vaccines in clinical studies.</jats:p

DEVELOPMENT OF AN IMPROVED EPSTEIN-BARR VIRUS (EBV) NEUTRALIZING ANTIBODY ASSAY TO FACILITATE DEVELOPMENT OF A PROPHYLACTIC GP350-SUBUNIT EBV VACCINE

No licensed vaccine is available for prevention of EBV-associated diseases, and robust, sensitive, and high-throughput bioanalytical assays are needed to evaluate immunogenicity of gp350 subunit-based candidate EBV vaccines. Here we have developed and improved analytical tools for such a vaccine’s pre-clinical and clinical validation including a gp350-specific antibody detection assay and an EBV-GFP based neutralization assay for measuring EBV specific antibodies in human donors. The sensitivity of our previously published high-throughput EBV-GFP fluorescent focus (FFA)-based neutralization assay was further improved when guinea pig complement was supplemented using a panel of healthy human sera. Anti-gp350 antibody titers, which were evaluated using an anti-gp350 IgG ELISA assay optimized for capture and detection conditions, were moderately correlated to the FFA-based neutralization titers. Overall, these sensitive, and high-throughput bioanalytical assays are capable of characterizing the serologic response to natural EBV infection, with applications in evaluating EBV antibody status in epidemiologic studies and immunogenicity of candidate gp350-subunit EBV vaccines in clinical studies

Global analysis of gene expression in pulmonary fibrosis reveals distinct programs regulating lung inflammation and fibrosis

The molecular mechanisms of pulmonary fibrosis are poorly understood. We have used oligonucleotide arrays to analyze the gene expression programs that underlie pulmonary fibrosis in response to bleomycin, a drug that causes lung inflammation and fibrosis, in two strains of susceptible mice (129 and C57BL/6). We then compared the gene expression patterns in these mice with 129 mice carrying a null mutation in the epithelial-restricted integrin β6 subunit (β6(−/−)), which develop inflammation but are protected from pulmonary fibrosis. Cluster analysis identified two distinct groups of genes involved in the inflammatory and fibrotic responses. Analysis of gene expression at multiple time points after bleomycin administration revealed sequential induction of subsets of genes that characterize each response. The availability of this comprehensive data set should accelerate the development of more effective strategies for intervention at the various stages in the development of fibrotic diseases of the lungs and other organs