Cloning, Expression, and Functional Characterization of TL1A-Ig

Abstract

TNF superfamily member 15 (TL1A) is the ligand for TNFR superfamily (TNFRSF)25. We previously reported that TNFRSF25 stimulation with an agonist Ab, 4C12, expands pre-existing CD4+Foxp3+ regulatory T cells (Tregs) in vivo. To determine how the physiological ligand differs from the Ab, we generated a soluble mouse TL1A-Ig fusion protein that forms a dimer of TL1A trimers in solution with an apparent molecular mass of 516 kDa. In vitro, TL1A-Ig mediated rapid proliferation of Foxp3+ Tregs and a population of CD4+Foxp3− conventional T cells. TL1A-Ig also blocked de novo biogenesis of inducible Tregs and it attenuated the suppressive function of Tregs. TNFRSF25 stimulation by TL1A-Ig in vivo induced expansion of Tregs such that they increased to 30–35% of all CD4+ T cells in the peripheral blood within 5 d of treatment. Treg proliferation in vivo was dependent on TCR engagement with MHC class II. Elevated Treg levels can be maintained for at least 20 d with daily injections of TL1A-Ig. TL1A-Ig–expanded Tregs expressed high levels of activation/memory markers KLRG1 and CD103 and were highly suppressive ex vivo. TL1A-Ig–mediated Treg expansion in vivo was protective against allergic lung inflammation, a mouse model for asthma, by reversing the ratio of conventional T cells to Tregs in the lung and blocking eosinophil exudation into the bronchoalveolar fluid. Thus, TL1A-Ig fusion proteins are highly active and tightly controllable agents to stimulate Treg proliferation in vivo, and they are uniquely able to maintain high levels of expanded Tregs by repeated administration.

Treatment with agonistic DR3 antibody results in expansion of donor Tregs and reduced graft-versus-host disease

“…Recently, it was reported that murine TL1a-Ig fusion protein expanded preexisting Tregs in vivo. 44 On the other hand, it was also reported that the binding of TL1a to DR3 expressed on human T cells caused increased IFNg production and promoted Th1 differentiation in vitro. 45,46 Our data suggest that the major effects of the activation of DR3 signaling in vivo were caused by the expansion and activation of Tregs in donor mice.…”

The TNF Receptor Superfamily in Co-stimulating and Co-inhibitory Responses

“…Tnfsf15 −/− mice show disease severity in antigen-induced arthritis (Bull et al, 2008; Wang et al, 2013). DR3 activation either by agonistic antibody (4C12) (Schreiber et al, 2010), TL1A-Ig fusion protein (Khan et al, 2013), or TL1A transgenic mouse, induces Treg cell expansion. Two studies using TL1A transgenic mice reported that the engagement of DR3 on Treg cells dampens their suppressive function and exacerbates inflammation (Meylan et al, 2011; Taraban et al, 2011).…”

Co-stimulation with TNF receptor superfamily 4/25 antibodies enhances in-vivo expansion of CD4+CD25+Foxp3+ T cells (Tregs) in a mouse study for active DNA Aβ42 immunotherapy

“…The published data showed expansion of CD4+CD25+Foxp3+ cells in the context of co-stimulation or vaccination with a peak value at 5 to 6 days which was the half-life of the antibodies (Schreiber et al 2010 and 2012, Wolf et al 2012, Khan et al 2013). Thus, the possible expansion of antigen specific Tregs cells with this type of co-stimulation with DNA Aβ42 immunization prompted us to further characterize the T cell site.…”