Detection of human leukocyte antigen biomarkers in breast cancer utilizing label-free biosensor technology.

According to the American Cancer Society, more than 200,000 women will be diagnosed with invasive breast cancer each year and approximately 40,000 will die from the disease. The human leukocyte antigen (HLA) class I samples peptides derived from proteasomal degradation of cellular proteins and presents these fragments on the cell surface for interrogation by circulating cytotoxic T lymphocytes (CTL). Generation of T-cell receptor mimic (TCRm) monoclonal antibodies (mAbs) which recognize breast cancer specific peptide/HLA-A*02:01 complexes such as those derived from macrophage migration inhibitory factor (MIF19-27) and NY-ESO-1157-165 enable detection and destruction of breast cancer cells in the absence of an effective anti-tumor CTL response. Intact class I HLA/peptide complexes are shed by breast cancer cells and represent potentially relevant cancer biomarkers. In this work, a breakthrough biomarker screening system for cancer diagnostics incorporating T-cell receptor mimic monoclonal antibodies combined with a novel, label-free biosensor utilizing guided-mode resonance (GMR) sensor technology is presented. Detection of shed MIF/HLA-A*02:01 complexes in MDA-MB-231 cell supernatants, spiked human serum, and patient plasma is demonstrated. The impact of this work could revolutionize personalized medicine through development of companion disease diagnostics for targeted immunotherapies.

A novel T-cell receptor mimic defines dendritic cells that present an immunodominant West Nile virus epitope in mice.

We used a newly generated T-cell receptor mimic monoclonal antibody (TCRm MAb) that recognizes a known nonself immunodominant peptide epitope from West Nile virus (WNV) NS4B protein to investigate epitope presentation after virus infection in C57BL/6 mice. Previous studies suggested that peptides of different length, either SSVWNATTAI (10-mer) or SSVWNATTA (9-mer) in complex with class I MHC antigen H-2D(b) , were immunodominant after WNV infection. Our data establish that both peptides are presented on the cell surface after WNV infection and that CD8(+) T cells can detect 10- and 9-mer length variants similarly. This result varies from the idea that a given T-cell receptor (TCR) prefers a single peptide length bound to its cognate class I MHC. In separate WNV infection studies with the TCRm MAb, we show that in vivo the 10-mer was presented on the surface of uninfected and infected CD8α(+) CD11c(+) dendritic cells, which suggests the use of direct and cross-presentation pathways. In contrast, CD11b(+) CD11c(-) cells bound the TCRm MAb only when they were infected. Our study demonstrates that TCR recognition of peptides is not limited to certain peptide lengths and that TCRm MAbs can be used to dissect the cell-type specific mechanisms of antigen presentation in vivo.