A new nucleic acid–based agent inhibits cytotoxic T lymphocyte–mediated immune disorders

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Abstract

Background:

Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and graft-versus-host disease (GVHD) are distinct immune reactions elicited by drugs or allogeneic antigens; however, they share a pathomechanism with the activation of cytotoxic T lymphocytes (CTLs). CTLs produce cytotoxic proteins, cytokines, chemokines, or immune alarmins, such as granulysin (GNLY), leading to the extensive tissue damage and systemic inflammation seen in patients with SJS/TEN or GVHD. Currently, there is no effective therapeutic agent specific for CTL-mediated immune disorders.

Objectives:

By targeting GNLY+ CTLs, we aimed to develop a nucleic acid–based agent consisting of an anti-CD8 aptamer with GNLY small interfering RNA (siRNA).

Methods:

We performed systematic evolution of ligands using exponential enrichment to select and identify effective anti-CD8 aptamers. We developed an aptamer-siRNA chimera using a “sticky bridge” method by conjugating the aptamer with siRNA. We analyzed the inhibitory effects of the aptamer-siRNA chimera on CTL responses in patients with SJS/TEN or GVHD.

Results:

We identified a novel DNA aptamer (CD8AP17s) targeting CTLs. This aptamer could be specifically internalized into human CTLs. We generated the CD8AP17s aptamer–GNLY siRNA chimera, which showed a greater than 79% inhibitory effect on the production of GNLY by drug/alloantigen-activated T cells. The CD8AP17s aptamer–GNLY siRNA chimera decreased cytotoxicity inin vitromodels of both SJS/TEN (elicited by drug-specific antigen) and GVHD (elicited by allogeneic antigens).

Conclusions:

Our results identified a new nucleic acid–based agent (CD8 aptamer–GNLY siRNA chimera) that can significantly inhibit CTL-mediated drug hypersensitivity, such as that seen in patients with SJS/TEN, as well as the alloreactivity seen in patients with GVHD. This study provides a novel therapeutic strategy for CTL-mediated immune disorders.

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