The protein encoded by this gene is a component of the innate immune system. CD14 exists in two forms. Either it is anchored into the membrane by a glycosylphosphatidylinositol tail (mCD14) or it appears in a soluble form (sCD14). Soluble CD14 either appears after shedding of mCD14 (48 KDa) or is directly secreted from intracellular vesicles (56 KDa). CD14 takes its name from its inclusion in the cluster of differentiation group of cell surface marker proteins. CD14 was the first described pattern recognition receptor.