Interleukin-2 (IL-2) is a lymphokine with a range of crucial roles in immune activation and homeostasis. It is produced by a subset of activated T-lymphocytes and acts as a growth factor for T cells and NK cells, and promotes proliferation, activation-induced cell death, antibody secretion, and cytokine production in various cell types.
- Here we use Microfluidic Diffusional Sizing (MDS) on a Fluidity One instrument to assess the hydrodynamic radius (Rh) over a dilution series. We observe that the Rh increases with increasing concentration, in a manner which indicates a monomer-trimer equilibrium with positive cooperativity.
- This result challenges much of the modern literature which assumes a monomeric form, or in some instances a dimer.
- When the data was analysed, a Hill equation provides a better fit compared to a monomer-dimer equilibrium model. The steepness of the curve on the Hill equation fit indicates positive cooperativity in the assembly of the trimers.