Principal Investigator: Basil Golding, MD
Office / Division / Lab: OTAT / DPPT / PDB

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General Overview

The goal of our research is to enhance the safety of plasma-derived products, such as proteins used to treat clotting disorders, immune system disorders, and certain other diseases.

Our laboratory is pursuing this goal by developing tests that detect contamination of these products by substances released by microorganisms. Although microbes are filtered out of plasma used to make the products, the small molecules they make can escape filtration and trigger inflammation in individuals treated with the products.

Our tests use a variety of cells that carry molecules called toll-like receptors (TLRs) on their surface. Each group of cells carries a specific type of TLR, which detects and binds to a specific protein made by microorganisms. Tests based on this interaction between TLRs and these proteins, called TLR ligands, will help FDA and industry screen plasma-derived products for contamination by microorganisms or their products.

FDA will make any tests that we develop available to industry so they can be used to increase the safety of plasma-derived products.

More recent work from our laboratory invetigates the potential effects of viral contamination of our products on activation of endothelial cells via dsRNA and triggering of TLR3. Viruses, including DNA viruses, such as Dengue, may contaminate blood components and cause infections in recipients.

A crosscutting issue in the Public Health arena and an ongoing concern at the FDA is the possibility of Pandemic Influenza due to a bird flu' virus that through mutation becomes capable of passing from human to human. Avian influenza can bind to endothelial cells (EC) via the receptor, . During its life cycle influenza expresses dsRNA which can stimulate EC via TLR3. In our recent research we use Poly(I:C) as a surrogate for viral dsRNA and examine its effect on EC.

We show that Poly(I:C)can activate EC to secrete mutiple proinflammatory cytokines. In addition, Poly (I:C) activation of EC is accompanied by increased permeability of EC membranes. The latter is likely due to loss of claudin 5, a tight junction molecule from the EC plasma membrane. Our research probes the pathway involved. These findings may explain the observation that avian influenza is associated with more severe lung disease and may also provide new ways to treat the condition.

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Scientific Overview

Toll like receptors (TLRs) are naturally occurring pathogen-recognition receptors found on cells of the innate immune system in all species from drosophila to humans. We developed a panel of human cell lines that express TLRs that detect both human pathogens and compounds derived from these pathogens.

Plasma-derived products, such as immune globulins, albumin, and coagulation factors, are manufactured from plasma pools. Because certain parts of the manufacturing process are not performed under sterile conditions, some microbial contamination occurs. Therefore, products undergo sterile filtration of the bulk prior to being put into vials. Thus intact pathogens are removed, but compounds released from pathogens can remain in the final product. One of the commonest adverse effects of immune globulin administration is chills and fever, most likely due to presence of such compounds in the product.

Recombinant products made in bacteria or yeasts can also be contaminated with microbial compounds during the manufacturing process. Again, sterile filtration will remove the intact organisms but not the pro-inflammatory soluble compounds that can be present.

Current methods for detection of bacterial compounds are the rabbit pyrogen assay and the limulus amebocyte assay (LAL test). Both of these are based on reactivity of non-human cells and use animals.

In contrast, the method we have developed is based on the reactivity of human cells.

We established the utility of the method by showing that a recombinant product associated with serious adverse events in humans contained flagellin derived from E. coli, which was used as an expression vector. The final container testing of the product using routine methods did not detect this contaminant. In contrast, The panel of TLR cell lines that we developed showed that the product reacted with cells expressing TLR5, the ligand for flagellin. We demonstrated the specificity of this binding by inhibiting it with monoclonal anti-TLR5 antibody. We then used Western blot to show that the product contained flagellin, and confirmed that it was E. coli flagellin using mass spectrometry.

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Publications

AAPS J 2019 May 6;21(4):62
Fc-Fusion drugs have FcgammaR/C1q binding and signaling properties that may affect their immunogenicity.
Lagasse HAD, Hengel H, Golding B, Sauna ZE

Trends Biotechnol 2018 Oct;36(10):1068-84
Evaluating and mitigating the immunogenicity of therapeutic proteins.
Sauna ZE, Lagasse D, Pedras-Vasconcelos J, Golding B, Rosenberg AS

J Thromb Haemost 2017 Apr;15(4):721-34
Modulating immunogenicity of Factor IX by fusion to an immunoglobulin Fc domain: a study using hemophilia B mouse model.
Levin D, Lagasse HA, Burch E, Strome S, Tan S, Jiang H, Sauna ZE, Golding B

Am J Hematol 2017 Apr;92(4):E44-5
Association of immune globulin intravenous (IGIV) and thromboembolic adverse events (TEEs).
Ovanesov MV, Menis MD, Scott DE, Forshee R, Anderson S, Bryan W, Golding B

PLoS One 2016 Aug 9;11(8):e0160875
Poly(I:C) induces human lung endothelial barrier dysfunction by disrupting tight junction expression of claudin-5.
Huang LY, Stuart C, Takeda K, D'Agnillo F, Golding B

J Pathol 2016 Jan;238(1):85-97
1918 pandemic influenza virus and Streptococcus pneumoniae coinfection results in activation of coagulation and widespread pulmonary thrombosis in mice and humans.
Walters KA, D'Agnillo F, Sheng ZM, Kindrachuk J, Schwartzman LM, Keustner RE, Chertow DS, Golding BT, Taubenberger JK, Kash JC

Trends Biotechnol 2015 Jan;33(1):27-34
Fc fusion as a platform technology: potential for modulating immunogenicity.
Levin D, Golding B, Strome SE, Sauna ZE