Used in immunological research to quantify ULBP-1 protein levels in biological samples such as serum, plasma, or cell culture supernatants. Helps study immune responses, particularly in relation to natural killer (NK) cell activation, as ULBP-1 is a ligand for the NKG2D receptor. Commonly applied in research on viral infections, cancer, and autoimmune diseases to understand immune surveillance and cellular stress responses. Provides a reliable, sensitive, and specific method for detecting soluble ULBP-1, supporting biomarker discovery and mechanistic studies in human disease models.