Fig. 1.

T-cell proliferation study design. PBMCs were stimulated with anti-CD3 and cultured exposed to either PBS, SN, EVs, SAGM, or diluted plasma. The first experiment included four RBC units from which EVs, SN, and samples for NTA were obtained at early and late phases of storage. The experiments were continued utilizing SN (but no more EVs) sampled at various RBC unit storage ages. Altogether seven individual PBMCs were used in the experiments, utilizing always the same individuals when comparing fresh versus old RBCs. RBCs, stored red blood cells; BCs, buffy coats; SN, supernatant; EVs, extracellular vesicles; PBMCs, peripheral blood mononuclear cells; NTA, nanoparticle tracking analysis; SAGM, saline-adenine-glucose-mannitol – solution.