Profiling of cytokine expression by biotin-labeled-based protein arrays

Global analysis of protein expression holds great promise in basic research and patient care. Previously we demonstrated that multiple cytokines could be detected simultaneously using an enzyme-linked immunosorbent assay protein array system with high sensitivity and specificity. In this paper, we described a biotin-labeled-based protein array system to detect multiple cytokines simultaneously from biological samples. In this new approach, proteins from a variety of biological sources are labeled with biotin. The biotin-labeled proteins are then incubated with antibody chips. Targeted proteins are captured by the array antibodies spotted on the antibody chips. The presence of targeted proteins is detected using Cy3- or Cy5-conjugated streptavidin and signals are imaged by laser scanner. The system also can be easily adapted to a two-color binding assay, allowing measurement of the levels of proteins in a test sample with respect to a reference sample at the same chip. To demonstrate its potential applications, we applied this technology to profile human cytokines, chemokines, growth factors, angiogenic factors and proteases in estrogen receptor (ER)+ and ER- cells. These results suggest that biotin-labeled-based antibody chip technology can provide a practical and powerful means of profiling hundreds or thousands of proteins for research and clinical purposes.