Ocular Microbiology and Immunology Group
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2024 OMIG Abstract

In vivo TNFRSF25 and IL-2R Stimulation in Mice Induces a Regulatory Environment Within Multiple Tissues including the Ocular Adnexa that are Frequent Targets of GVHD

Duneia McManus¹, Symon Ma², Ali Khodor², Seitaro Komai², Miguel Gallardo¹, Victor L. Perez²
and Robert B. Levy<sup>1,2

1</sup>Department of Microbiology and Immunology, University of Miami, Miller School of Medicine, Miami, FL; ²Department of Ophthalmology, University of Miami, Miller School of Medicine, Miami, FL

Purpose: To investigate if the systemic administration of TL1A-Ig fusion protein and recombinant IL-2 (low dose) in murine recipients prior to bone marrow transplant: 1) induces increased levels of Tregs in GVHD target tissues, including the ocular adnexa and 2) is associated with an immunosuppressive environment that suppresses conventional T cell responses.

Methods: Recipient CD45.2 BALB/c mice were either untreated or treated with TL1A-Ig fusion protein (FP: 40 μg on D 1-4 and / or rhIL-2 low dose; (rhIL-2LD:10000 units, D 4-6). On D.8, the ocular adnexa (conjunctiva and lacrimal gland) and other target organs of GVHD (skin, liver, colon, and lung) were harvested and single cell suspensions prepared for 1) flow cytometric analysis and 2) in vitro culture with/without 1g α-CD3 mAb for 120 hrs and counted to assess suppressive functional activity in these tissue compartments.

Results: Flow cytometric analysis revealed that administration of TL1A-Ig FP and IL-2LD in mice lead to a mean frequency of 48.5% and 42.9% FoxP3+CD4+/ CD4+ T cells (2.1 and 2.5x increase) compared to non-treated mice in the conjunctiva and lacrimal gland respectively. Treg numbers and frequency were also found to be increased in the liver, colon, skin and lung. Notably, following this in vivo treatment, anti-CD3 mAb stimulation of conventional T cells present in liver, lacrimal gland and conjunctiva cell cultures did not result in increased T cell numbers compared to cultures from untreated mice. TL1A-Ig FP and IL-2LD pretreated animals administered a BMT, exhibited decreased GVHD.

Conclusions: In vivo administration of TL1A-Ig FP and IL-2LD stimulating the TNFRSF25 and high-affinity IL-2R on Tregs results in their marked and rapid expansion in hematopoietic and non-hematopoietic tissues, including the conjunctiva and lacrimal gland. Importantly, this expansion enhances Treg function and is associated with inhibition of conventional T cell responses to T cell receptor stimulation in multiple tissues that undergo GVHD inflammation. Ongoing experiments are exploring the effects of local administration of these reagents on ocular immunoregulatory cell populations and amelioration of ophthalmic complications associated with GVHD that impact quality of life.


Disclosure:

N (DM, SM, AK, SK, MG); S 3R01EY030283-04S1; (RBL/VLP, NEIR01EY024484; NEIR01EY030283; RBL, Applebaum Foundation Award); C (VLP, RBL); E (VLP, RBL); O (VLP, RBL); P (VLP, RBL)