CD4+ T cell activation, function, and metabolism are inhibited by very low concentrations of DMSO

Dimethyl sulfoxide (DMSO) is a polar organic solvent ubiquitously used in a wide range of biological applications and research areas. DMSO is toxic for cells at high concentrations, but its toxicity at low concentrations is insufficiently investigated. DMSO is routinely used as a cryoprotectant for long term cell freezing as well as to dissolve peptides and drugs for immune cell functional assays with concentrations up to 1% of DMSO not uncommon in in vitro T cell assays.

Human CD4⁺ T cell activation, cytokine production, proliferation, and metabolism were investigated after stimulation in the presence of DMSO at concentrations from 0.01% to 1%.

Polyclonal activation of CD4⁺ T cells as defined by the expression of CD69, CD25 and CD154 was inhibited by DMSO already at a concentration of 0.25%. The frequencies of IL-21⁺, IL-4⁺, and IL-22⁺ T cells following polyclonal activation were variably inhibited by DMSO from concentrations ranging from 0.25% to 1%, whereas IFNg⁺ cells were unaffected up to a concentration of 1% DMSO. CD4⁺ T cell proliferation after anti-CD3 or antigen stimulation was inhibited by 0.5% DMSO and completely inhibited by 1% DMSO. Glucose uptake was inhibited at 1% DMSO, but only minor effects on cell respiration were observed in the presence of DMSO up to 1%.

The present study revealed that DMSO affects T cell responses at very low concentrations. Furthermore, T cell functional assays were affected by different DMSO concentration thresholds. We, therefore, urge care when adding DMSO-containing preparations to T cell cultures.