Our ability to analyze adaptive immunity and engineer its activity has long been constrained by our limited ability to identify native pairs of heavy-light antibody chains and alpha-beta T-cell receptor (TCR) chains - both of which comprise coupled "halves of a key", collectively capable of recognizing specific antigens. Here we report a cell-based emulsion RT-PCR approach that allows the selective fusion of the native pairs of amplified TCR alpha and beta chain genes for complex samples. A new type of PCR suppression technique was developed that makes it possible to amplify the fused library with minimal noise for subsequent analysis by high-throughput paired-end Illumina sequencing. With this technique, single analysis of a complex blood sample allows identification of multiple native TCR chain pairs. This approach may be extended to identify native antibody chain pairs and, more generally, pairs of mRNA molecules that are co-expressed in the same living cells. This article is protected by copyright. All rights reserved.