biostudies-literatureUnknown11(1)Kleiman EJSR Life Sciences, LLCExtracellular adenosine suppresses T cell immunity in the tumor microenvironment and in vitro treatment of memory T cells with adenosine can suppress antigen-mediated memory T cell expansion. We describe utilizing the recall antigen assay platform to screen small molecule drug off-target effects on memory T cell expansion/function using a dosing regimen based on adenosine treatment. As a proof of principle, we show low dose GS-5734, a monophosphoramidate prodrug of an adenosine analog, does not alter memory T cell recall at lower doses whereas toxicity observed at high dose favors antigen-specific memory T cell survival/proliferation over non-specific CD8⁺ T cells. Conversely, parent nucleoside GS-441524 at high dosage does not result in cellular toxicity and reduces antigen-speScientific reports9561https://www.ebi.ac.uk/biostudies/studies/S-EPMC8100288biostudies-literatureAdenosine-related small molecules show utility of recall antigen assay to screen compounds for off-target effects on memory T cells.PMC8100288Kleiman EMagcase DMao BDaftarian PMSierra GGeorge MVfalseAdenosine-related small molecules show utility of recall antigen assay to screen compounds for off-target effects on memory T cells.Extracellular adenosine suppresses T cell immunity in the tumor microenvironment and in vitro treatment of memory T cells with adenosine can suppress antigen-mediated memory T cell expansion. We describe utilizing the recall antigen assay platform to screen small molecule drug off-target effects on memory T cell expansion/function using a dosing regimen based on adenosine treatment. As a proof of principle, we show low dose GS-5734, a monophosphoramidate prodrug of an adenosine analog, does not alter memory T cell recall at lower doses whereas toxicity observed at high dose favors antigen-specific memory T cell survival/proliferation over non-specific CD8⁺ T cells. Conversely, parent nucleoside GS-441524 at high dosage does not result in cellular toxicity and reduces antigen-spe2021-01-01T00:00:00Z2021 May2026-05-08T09:39:49.668Z2022-02-10T09:33:20.103ZS-EPMC81002883395325610.1038/s41598-021-88965-3