Patent ID: 7091046

Claim:
A multiplexed method of detecting a plurality of target polypeptides in a sample composition, the method comprising: a) contacting the sample composition with genetic packages that each display a polypeptide-binding component under conditions whereby the plurality of target polypeptides in the sample form complexes with displayed polypeptide-binding components specific therefor, wherein: each genetic package comprises a predetermined marker component that is indicative of the displayed polypeptide-binding component; and the polypeptide-binding component specifically binds to at least one of the target polypeptides, whereby target polypeptides that bind thereto can be identified by virtue of the marker component; and wherein the genetic packages are selected from the group consisting of a bacteriophage, a virus and a bacterium; b) separating complexes of the plurality of target polypeptides with the displayed polypeptide-binding components on the genetic packages from the sample composition; c) optionally amplifying the genetic packages that have formed complexes, resulting in amplified genetic packages, or amplifying the marker components in the genetic packages that have formed complexes; d) identifying marker components in the genetic packages that have formed complexes, thereby detecting the plurality of target polypeptides in the sample, wherein: identification of a marker component is effected by mass spectrometry; and identification of a marker component indicates the presence of a target polypeptide in the sample.