Global view of biological processes and molecular functions of HDL proteins. Proteins detected in HDL were associated with biological functions using Gene Ontology process annotations. This approach demonstrated significant overrepresentation of proteins involved in several categories, including lipid metabolism (P = 10−15), the immune response (P = 10−6), protease inhibitor activity (P = 10−7), antigen processing (P = 10−3), and the acute-phase response (P = 10−5).