A system for rapid detection of analytes, comprising: (a) a living, engineered biosensor cell, wherein the living, engineered biosensor cell is derived from a cellular component of the mammalian immune system; (b) a reporter protein, wherein the reporter protein is engineered into and expressed by the living, engineered biosensor cell, and wherein the reporter protein emits a detectable signal in response to certain predetermined cytosolic changes in the living, engineered biosensor cell; (c) a signal transduction pathway engineered into or occurring naturally within the living, engineered biosensor cell, wherein the signal transduction pathway controls a biological process within the cytosol of the living, engineered biosensor cell, and wherein the biological process, when it occurs, causes the reporter protein to emit a detectable signal; (d) at least one type of detector molecule, wherein each detector molecule is adapted to bind to a specific analyte; (e) at least one analyte, wherein the at least one analyte binds to the detector molecule that is specific to that analyte; (f) a plurality of transmembrane, non-antibody signal transducing elements expressed by the living, engineered biosensor cell, wherein each signal transducing element is adapted to receive a detector molecule; and (g) wherein upon the binding of a sufficient number of analytes to a sufficient number of detector molecules that are themselves bound to transmembrane non-antibody signal transducing elements, an aggregation of signal transducing elements occurs on the biosensor cell surface, the signal transduction pathway is activated, the biologicalprocess occurs, and the detectable signal is emitted by the reporter protein. (a) a living, engineered biosensor cell, wherein the living, engineered biosensor cell is derived from a cellular component of the mammalian immune system; (b) a reporter protein, wherein the reporter protein is engineered into and expressed by the living, engineered biosensor cell, and wherein the reporter protein emits a detectable signal in response to certain predetermined cytosolic changes in the living, engineered biosensor cell; (c) a signal transduction pathway engineered into or occurring naturally within the living, engineered biosensor cell, wherein the signal transduction pathway controls a biological process within the cytosol of the living, engineered biosensor cell, and wherein the biological process, when it occurs, causes the reporter protein to emit a detectable signal; (d) at least one type of detector molecule, wherein each detector molecule is adapted to bind to a specific analyte; (e) at least one analyte, wherein the at least one analyte binds to the detector molecule that is specific to that analyte; (f) a plurality of transmembrane, non-antibody signal transducing elements expressed by the living, engineered biosensor cell, wherein each signal transducing element is adapted to receive a detector molecule; and (g) wherein upon the binding of a sufficient number of analytes to a sufficient number of detector molecules that are themselves bound to transmembrane non-antibody signal transducing elements, an aggregation of signal transducing elements occurs on the biosensor cell surface, the signal transduction pathway is activated, the biologicalprocess occurs, and the detectable signal is emitted by the reporter protein.