Theranostics 2015; 5(11):1275-1290. doi:10.7150/thno.12989

Research Paper

Zigzag Generalized Lévy Walk: the In Vivo Search Strategy of Immunocytes

Hui Li1, 2, *, Shuhong Qi1, 2, *, Honglin Jin3, Zhongyang Qi1, 2, Zhihong Zhang1, 2, Ling Fu1, 2, †, ✉, Qingming Luo1, 2, †, ✉

1. Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan 430074, China.
2. MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
3. Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
*H.L. and S.Q. contributed equally to this work.
L.F. and Q.L. contributed equally to this work.

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Citation:
Li H, Qi S, Jin H, Qi Z, Zhang Z, Fu L, Luo Q. Zigzag Generalized Lévy Walk: the In Vivo Search Strategy of Immunocytes. Theranostics 2015; 5(11):1275-1290. doi:10.7150/thno.12989. Available from http://www.thno.org/v05p1275.htm

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Abstract

Immune responses are based on the coordinated searching behaviors of immunocytes that are aimed at tracking down specific targets. The search efficiency of immunocytes significantly affects the speed of initiation and development of immune responses. Previous studies have shown that not only the intermittent walk but also the zigzag turning preference of immunocytes contributes to the search efficiency. However, among existing models describing immunocytes' search strategy, none has captured both features. Here we propose a zigzag generalized Lévy walk model to describe the search strategy of immunocytes more accurately and comprehensively by considering both the intermittent and the zigzag-turning walk features. Based on the analysis of the searching behaviors of typical immune cell types, dendritic cells and leukocytes, in their native physiological environment, we demonstrate that the model can describe the in vivo search strategy of immunocytes well. Furthermore, by analyzing the search efficiency, we find that this type of search strategy enables immunocytes to capture rare targets in approximately half the time than the previously proposed generalized Lévy walk. This study sheds new light on the fundamental mechanisms that drive the efficient initiation and development of immune responses and in turn may lead to the development of novel therapeutic approaches for diseases ranging from infection to cancer.

Keywords: Search strategy, dendritic cell, leukocyte, amoeboid-manner crawling, zigzag walk, Lévy walk