DR3 is a death domain-containing receptor that is upregulated during T cell activation and whose overexpression induces apoptosis and NF-kappaB activation in cell lines. Here we show that an endothelial cell-derived TNF-like factor, TL1A, is a ligand for DR3 and decoy receptor TR6/DcR3 and that its expression is inducible by TNF and IL-1alpha. TL1A induces NF-kappaB activation and apoptosis in DR3-expressing cell lines, while TR6-Fc protein antagonizes these signaling events. Interestingly, in T cells, TL1A acts as a costimulator that increases IL-2 responsiveness and secretion of proinflammatory cytokines both in vitro and in vivo. Our data suggest that interaction of TL1A with DR3 promotes T cell expansion during an immune response, whereas TR6 has an opposing effect.

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The large-scale production of recombinant human monoclonal antibodies demands economical purification processes with high throughputs. In this article we briefly describe a common antibody process and evaluate the Q membrane adsorber for process-scale antibody production as an alternative to a Q-packed-bed column in a flow-through mode. The scientific concepts underlining Q membrane technology and its application are reviewed. The disadvantages and advantages of using Q membrane chromatography as a purification unit in large-scale production are discussed, including problems initially seen with the Q membrane scale-down model but solved with the invention of a new scale-down model. The new Q-membrane unit operation has a process capacity greater than 3,000 g/m(2) or 10.7 kg/L with a LRV over 5 for four model viruses. In this Review, a cost analysis illustrates that Q membrane chromatography is a viable alternative to Q column chromatography as a polishing step in a flow-through mode for process-scale antibody production.

Interferon-␣ (IFN-␣) is indicated for the treatment of certain viral infections including hepatitis B and C, and cancers such as melanoma. The short circulating half-life of unmodified IFN-␣ makes frequent dosing (daily or three times weekly) over an extended period (6 -12 months or more) necessary. To improve the pharmacokinetics of IFN-␣ and decrease dosing frequency, IFN-␣ was fused to human serum albumin producing a new protein, Albuferon. In vitro comparisons of Albuferon and IFN-␣ showed similar antiviral and antiproliferative activities, although Albuferon was less potent on a molar basis than IFN-␣. Pharmacokinetic and pharmacodynamic properties of the fusion protein were enhanced in monkeys. After a single intravenous injection (30 g/kg,) clearance was 0.9 ml/h/kg, and the terminal half-life was 68 h. After 30 g/kg subcutaneous injection, apparent clearance (clearance divided by bioavailability) was 1.4 ml/h/kg, the terminal half-life was 93 h, and bioavailability was 64%. The rate of clearance of Albuferon was approximately 140-fold slower, and the half-life 18-fold longer, than for IFN-␣ given by the subcutaneous route in other monkey studies. Sera from Albuferon-treated monkeys demonstrated doserelated antiviral activity for Ն8 days based on an in vitro bioassay, whereas antiviral activity from IFN-␣-treated animals was only slightly elevated relative to vehicle on day 0. Significant increases in 2Ј,5Ј-oligoadenylate synthetase mRNA relative to IFN-␣-or vehicle-treated animals were maintained for Ն10 days after subcutaneous dosing. The improved pharmacokinetics of Albuferon are accompanied by an improved pharmacodynamic response suggesting that Albuferon may offer the benefits of less frequent dosing and a potentially improved efficacy profile compared with IFN-␣.

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A coordinated effort combining bioinformatic tools with high-throughput cell-based screening assays was implemented to identify novel factors involved in T-cell biology. We generated a unique library of cDNAs encoding predicted secreted and transmembrane domain-containing proteins generated by analyzing the Human Genome Sciences cDNA database with a combination of two algorithms that predict signal peptides. Supernatants from mammalian cells transiently transfected with this library were incubated with primary T cells and T-cell lines in several high-throughput assays. Here we describe the discovery of a T cell factor, TIP (T cell immunomodulatory protein), which does not show any homology to proteins with known function. Treatment of primary human and murine T cells with TIP in vitro resulted in the secretion of IFN-gamma, TNF-alpha, and IL-10, whereas in vivo TIP had a protective effect in a mouse acute graft-versus-host disease (GVHD) model. Therefore, combining functional genomics with high-throughput cell-based screening is a valuable and efficient approach to identifying immunomodulatory activities for novel proteins.