Antigens are peptides or recombinant or native dependent on the production method.Complexes, systems, regulators, immune RNAs and non immune controls that can react with a specific antigen epitope.Whole adhesion and interacting molecules are present in lysates used as reference for ELISA quantification of these molecules and their subunits.The receptors are ligand binding factors of type 1, 2 or 3 and protein-molecules that receive chemical-signals from outside a cell. When such chemical-signals couple or bind to a receptor, they cause some form of cellular/tissue-response, e.g. a change in the electrical-activity of a cell. In this sense, am olfactory receptor is a protein-molecule that recognizes and responds to endogenous-chemical signals, chemokinesor cytokines e.g. an acetylcholine-receptor recognizes and responds to its endogenous-ligand, acetylcholine. However, sometimes in pharmacology, the term is also used to include other proteins that are drug-targets, such as enzymes, transporters and ion-channels.