Scalable transient protein expression.

Transient transfection is a well-established method to rapidly express recombinant proteins from mammalian cells. Accelerating activity in biotherapeutic drug development, demand for protein-based reagents, vaccine research, and large initiatives in structural and functional studies of proteins have propelled the need to generate moderate to high amounts of recombinant proteins and other macromolecules in a flexible and rapid manner. Progress over the last 10-15 years has demonstrated that transient transfections can be reliably and readily scaled up to handle milliliters to tens of liters of cells in suspension culture and obtain milligrams to grams of recombinant protein in a process that requires only days to weeks.

A phase 1 study of PAmAb, a fully human monoclonal antibody against Bacillus anthracis protective antigen, in healthy volunteers.

Background: Inhibition of the binding of Bacillus anthracis protective antigen (PA) to its cellular receptor can abrogate the downstream toxin-mediated deleterious effects of the anthrax toxin. A fully human monoclonal antibody against B. anthracis PA, PAmAb, was previously shown to provide a survival advantage in rabbit and monkey models of inhalational anthrax.

Scalable purification of Bacillus anthracis protective antigen from Escherichia coli.

The anthrax toxin consists of three proteins, protective antigen (PA), lethal factor, and edema factor that are produced by the Gram-positive bacterium, Bacillus anthracis. Current vaccines against anthrax use PA as their primary component. In this study, we developed a scalable process to produce and purify multi-gram quantities of highly pure, recombinant PA (rPA) from Escherichia coli.

Development of an edema factor-mediated cAMP-induction bioassay for detecting antibody-mediated neutralization of anthrax protective antigen.

Intoxication of mammalian cells by Bacillus anthracis requires the coordinate activity of three distinct bacterial proteins: protective antigen (PA), edema factor (EF), and lethal factor (LF). Among these proteins, PA has become the major focus of work on monoclonal antibodies and vaccines designed to treat or prevent anthrax infection since neither EF nor LF is capable of inducing cellular toxicity in its absence. Here, we present the development of a sensitive, precise, and biologically relevant bioassay platform capable of quantifying antibody-mediated PA neutralization.