Characterization of an Anti-Ebola Virus Hyperimmune Globulin Derived From Convalescent Plasma.

BACKGROUND: Convalescent plasma has been used to treat many viral diseases including Ebola. The manufacture of a purified anti-Ebola virus (EBOV) intravenous immunoglobulin (IVIG) from pooled convalescent plasma is described in this paper. METHODS: An enzyme-linked immunosorbent assay (ELISA) targeting an EBOV surface glycoprotein antigen was used to determine the immunoglobulin titer of pooled plasma and purified anti-EBOV IVIG. Anti-EBOV IVIG was also tested in neutralization assays using a vesicular stomatitis virus pseudovirion expressing EBOV glycoprotein on its surface and with live EBOV. Finally, the efficacy of the anti-EBOV IVIG was assessed in a mouse model of EBOV infection. RESULTS: In the ELISA, the anti-EBOV IVIG was shown to have a 7-fold increase in immunoglobulin G (IgG) titer over pooled convalescent plasma. In both the pseudovirion and live virus assays, the anti-EBOV IVIG showed approximately 5- to 6-fold increased potency over pooled plasma. Anti-EBOV IVIG also significantly improved survivability in mice infected with the virus when administered concurrently or 2 days after infection. CONCLUSIONS: These data support this purified anti-EBOV IVIG merits additional investigation and clinical trials for treatment and postexposure prophylaxis of Ebola virus disease. The experience gained can be applied to manufacture hyperimmune globulins against other emerging viruses.

Effects of mannose-binding lectin on pulmonary gene expression and innate immune inflammatory response to ozone.

Ozone is a common, potent oxidant pollutant in industrialized nations. Ozone exposure causes airway hyperreactivity, lung hyperpermeability, inflammation, and cell damage in humans and laboratory animals, and exposure to ozone has been associated with exacerbation of asthma, altered lung function, and mortality. The mechanisms of ozone-induced lung injury and differential susceptibility are not fully understood. Ozone-induced lung inflammation is mediated, in part, by the innate immune system. We hypothesized that mannose-binding lectin (MBL), an innate immunity serum protein, contributes to the proinflammatory events caused by ozone-mediated activation of the innate immune system. Wild-type (Mbl(+/+)) and MBL-deficient (Mbl(-/-)) mice were exposed to ozone (0.3 ppm) for up to 72 h, and bronchoalveolar lavage fluid was examined for inflammatory markers. Mean numbers of eosinophils and neutrophils and levels of the neutrophil attractants C-X-C motif chemokines 2 [Cxcl2 (major intrinsic protein 2)] and 5 [Cxcl5 (limb expression, LIX)] in the bronchoalveolar lavage fluid were significantly lower in Mbl(-/-) than Mbl(+/+) mice exposed to ozone. Using genome-wide mRNA microarray analyses, we identified significant differences in transcript response profiles and networks at baseline [e.g., nuclear factor erythroid-related factor 2 (NRF2)-mediated oxidative stress response] and after exposure (e.g., humoral immune response) between Mbl(+/+) and Mbl(-/-) mice. The microarray data were further analyzed to discover several informative differential response patterns and subsequent gene sets, including the antimicrobial response and the inflammatory response. We also used the lists of gene transcripts to search the LINCS L1000CDS(2) data sets to identify agents that are predicted to perturb ozone-induced changes in gene transcripts and inflammation. These novel findings demonstrate that targeted deletion of Mbl caused differential levels of inflammation-related gene sets at baseline and after exposure to ozone and significantly reduced pulmonary inflammation, thus indicating an important innate immunomodulatory role of the gene in this model.

A genetic model of differential susceptibility to human respiratory syncytial virus (RSV) infection.

Respiratory syncytial virus (RSV) is the primary cause of lower respiratory tract infection during childhood and causes severe symptoms in some patients, which may cause hospitalization and death. Mechanisms for differential responses to RSV are unknown. Our objective was to develop an in vitro model of RSV infection to evaluate interindividual variation in response to RSV and identify susceptibility genes. Populations of human-derived HapMap lymphoblastoid cell lines (LCLs) were infected with RSV. Compared with controls, RSV-G mRNA expression varied from ~1- to 400-fold between LCLs. Basal expression of a number of gene transcripts, including myxovirus (influenza virus) resistance 1 (MX1), significantly correlated with RSV-G expression in HapMap LCLs. Individuals in a case-control population of RSV-infected children who were homozygous (n=94) or heterozygous (n=172) for the predicted deleterious A allele in a missense G/A SNP in MX1 had significantly greater risk for developing severe RSV disease relative to those with the major allele (n=108) (χ(2)=5.305, P=0.021; OR: 1.750, 95% CI: 1.110, 2.758, P=0.021). We conclude that genetically diverse human LCLs enable identification of susceptibility genes (e.g., MX1) for RSV disease severity in children, providing insight for disease risk.

Plasma Donors in the Southwestern United States Positively Contribute to the Diverse Therapeutic Antibody Profile of Immune Globulin Products.

Human-plasma-derived immune globulin (IG) is used in augmentation therapy to provide protective levels of antibodies to patients with primary immune deficiency diseases (PIDD) and for prophylaxis against infectious diseases. To maintain the breadth of antibodies necessary for clinical protection, it is important to understand regional patterns of antibody seroprevalence in source plasma from which IG products are manufactured. In this study, source plasma from donation centers in various locations of the Southwestern quarter of the United States was surveyed for antibody titers to hepatitis A virus (HAV), measles virus (MeV), and cytomegalovirus (CMV). A broad range of anti-HAV Ig plasma titers was observed among these centers, with some centers exhibiting 3-5 times the titers of the others. Minor to no differences were observed for levels of anti-MeV and anti-CMV, respectively. Importantly, elevated anti-HAV Ig titers were broadly observed across plasma units obtained from the centers exhibiting high titers, indicative of a potential regional phenomenon among donors as opposed to few donors with singularly high titers. Plasma from these high-titer centers conferred significantly greater neutralization against HAV in vitro. The outcomes of this study give a glimpse of the antibody diversity inherent in human plasma used to manufacture IG products..

Diesel exhaust enhances influenza virus infections in respiratory epithelial cells.

Several factors, such as age and nutritional status, can affect the susceptibility to influenza infections. Moreover, exposure to air pollutants, such as diesel exhaust (DE), has been shown to affect respiratory virus infections in rodent models. Influenza virus primarily infects and replicates in respiratory epithelial cells, which are also a major targets for inhaled DE. Using in vitro models of human respiratory epithelial cells, we determined the effects of an aqueous-trapped solution of DE (DE(as)) on influenza infections. Differentiated human nasal and bronchial epithelial cells, as well as A549 cells, were exposed to DE(as) and infected with influenza A/Bangkok/1/79. DE(as) enhanced the susceptibility to influenza virus infection in all cell models and increased the number of influenza-infected cells within 24 h post-infection. This was not caused by suppressing antiviral mediator production, since interferon (IFN) beta levels, IFN-dependent signaling, and IFN-stimulated gene expression were also enhanced by exposure to DE(as). Many of the adverse effects induced by DE exposure are mediated by oxidative stress. Exposure to DE(as) used in these studies generated oxidative stress in respiratory epithelial cells, and addition of the antioxidant glutathione-ethylester (GSH-ET) reversed the effects of DE(as) on influenza infections. Furthermore, DE(as) increased influenza virus attachment to respiratory epithelial cells within 2 h post-infection. Taken together, the results presented here suggest that in human respiratory epithelial cells oxidative stress generated by DE(as) increases the susceptibility to influenza infection and that exposure to DE(as) increases the ability of the virus to attach to and enter respiratory epithelial cells.

Localization of type I interferon receptor limits interferon-induced TLR3 in epithelial cells.

Previous studies have shown that influenza infections increase Toll-like receptor 3 (TLR3) expression and that type I interferons (IFNs) may play a role in this response. This study aimed to expand on the role of type I IFNs in the influenza-induced upregulation of TLR3 and determine whether and how the localization of the IFN-alpha/beta receptor (IFNAR) in respiratory epithelial cells could modify IFN-induced responses. Using differentiated primary human airway epithelial cells this study demonstrates that soluble mediators secreted in response to influenza infection upregulate TLR3 expression in naive cells. This response was associated with an upregulation of type I IFNs and stimulation with type I, but not type II, IFNs enhanced TLR3 expression. Interestingly, although influenza infection results in IFN-beta release both toward the apical and basolateral sides of the epithelium, TLR3 expression is only enhanced in cells stimulated with IFN-beta from the basolateral side. Immunohistochemical analysis demonstrates that IFNAR expression is limited to the basolateral side of differentiated human airway epithelial cells. However, non- or poorly differentiated epithelial cells express IFNAR more toward the apical side. These data demonstrate that restricted expression of the IFNAR in the differentiated airway epithelium presents a potential mechanism of regulating type I IFN-induced TLR3 expression.