Interleukin 1 Alpha (IL1a) is a pivotal pro-inflammatory cytokine belonging to the interleukin-1 (IL-1) family, first identified for its role in mediating immune and inflammatory responses. It is synthesized as a precursor (pro-IL1a) primarily in immune cells like macrophages, monocytes, and dendritic cells, as well as non-immune cells such as epithelial and endothelial cells. Unlike its homolog IL1β, pro-IL1a retains biological activity without needing cleavage by caspase-1, though it can also be processed into a mature form. IL1a acts locally at sites of tissue damage or infection to trigger inflammation, recruit immune cells, and regulate cell proliferation and survival. Critically, IL1a exerts its effects by directly binding to Interleukin 1 Receptor Type I (IL1R1) on target cell surfaces.
To detect the activity of recombinant IL1a, a functional ELISA assay was performed to evaluate the interaction between recombinant human IL1a and recombinant human IL1R1.Briefly, biotin-linked IL1a were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100µl were then transferred to IL1R1-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST 3 times and incubation with Streptavidin-HRP for 30min, then wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50µl stop solution to the wells and read at 450nm immediately. The binding activity of IL1a and IL1R1 was shown in Figure 1, the EC50 for this effect is 0.15147µg/mL.