Biophysical Society Thematic Meeting - June 28-July 1, 2015

New Biological Frontiers Illuminated by Molecular Sensors and Actuators

Monday Speaker Abstracts

Genetically Encoded Tools to Manipulate and Observe Cellular Dynamics in Cardiac Disease Modelling and Drug Screening Yu-Fen Chang , Frances Book, Mark J. Davies, Matthew J. Daniels. University of Oxford, Oxford, United Kingdom. See abstract: Pos-5 Board 5 Intravital Microscopy of Fluorescent Protein Model Antigen-Elicited Specific Immune Response Zhihong Zhang . Huazhong University of Science and Technology, Wuhan, China. Intravital optical imaging provided a useful approach for clarifying how, when, and where the immune cells involved in tumor immunity. Model antigens have been widely used to simplify the investigation of complicated anti-tumor immune response. However, the classical model antigens (e.g., OVA) cannot be directly detected without fluorescent labeling. Thus, it’s necessary to develop a visualized model antigen system based on fluorescent protein itself for the intravital imaging of tumor immunity. Fluorescent protein KatushkaS158A displayed perfect optical characters and was quite suitable for optical imaging in vivo. The data indicated that it elicited both cellular and humoral immune response in the immunized C57BL/6 mice, resulting in the attenuation of the tumorigenesis of KatushkaS158A-expressing melanoma cells (K-B16) in vivo. To visualize the specific anti-tumor immune response in tumor microenvironment, EGFP-transgenic C57BL/6 mice were immunized twice with IFA-emulsified KatushkaS158A on Day 14 and Day 7 before the implantation of K-B16 cells into the dorsal skin-fold window chambers. The intravital imaging data indicated that strong and specific immune response against K-B16 cells was occurred in the KatushkaS158A-immunized mice at 2 days after the implantation of K-B16 cells, which swarms of EGFP+ immunocytes rushed toward the tumor cells with significantly higher motility and retained in the middle of the tumor area with high density. These responsive immunocytes eliminated K-B16 cells and blocked the growth of melanoma cells in vivo. Thus, KatushkaS158A protein was not only acted as a fluorescent marker for tumor imaging, but also used as a model antigen to elicit specific tumor immune response in C57BL/6 mice.

17