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Updated: May 8, 2026

A TIRF Microscopy Technique for Real-time, Simultaneous Imaging of the TCR and its Associated Signaling Proteins
Published on: March 22, 2012
TLR4 signaling shapes B cell dynamics via MyD88-dependent pathways and Rac GTPases
Laura Barrio1, Julia Saez de Guinoa, Yolanda R Carrasco
1Laboratorio de la Dinámica de las Células B, Departamento de Inmunología y Oncología, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Cientificas, Madrid E-28049, Spain.
Abstract:
B cells use a plethora of TLR to recognize pathogen-derived ligands. These innate signals have an important function in the B cell adaptive immune response and modify their trafficking and tissue location. The direct role of TLR signaling on B cell dynamics nonetheless remains almost entirely unknown. In this study, we used a state-of-the-art two-dimensional model combined with real-time microscopy to study the effect of TLR4 stimulation on mouse B cell motility in response to chemokines. We show that a minimum stimulation period is necessary for TLR4 modification of B cell behavior. TLR4 stimulation increased B cell polarization, migration, and directionality; these increases were dependent on the MyD88 signaling pathway and did not require ERK or p38 MAPK activity downstream of TLR4. In addition, TLR4 stimulation enhanced Rac GTPase activity and promoted sustained Rac activation in response to chemokines. These results increase our understanding of the regulation of B cell dynamics by innate signals and the underlying molecular mechanisms.
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