Biophysical Techniques to Study B Cell Activation: Single-Molecule Imaging and Force Measurements

2018 ◽  
pp. 51-68 ◽  
Author(s):  
Ivan Rey ◽  
David A. Garcia ◽  
Brittany A. Wheatley ◽  
Wenxia Song ◽  
Arpita Upadhyaya
Keyword(s):  
B Cell ◽  
Single Molecule ◽  
Cell Activation ◽  
Single Molecule Imaging ◽  
B Cell Activation ◽  
Force Measurements ◽  
Biophysical Techniques

scholarly journals Utilization of a photoactivatable antigen system to examine B-cell probing termination and the B-cell receptor sorting mechanisms during B-cell activation

2016 ◽  
Vol 113 (5) ◽  
pp. E558-E567 ◽  
Author(s):  
Jing Wang ◽  
Shan Tang ◽  
Zhengpeng Wan ◽  
Yiren Gao ◽  
Yiyun Cao ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Single Molecule ◽  
Cell Activation ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Antigen Binding ◽  
B Cell Activation ◽  
Class I Mhc ◽  
Antigen System

Antigen binding to the B-cell receptor (BCR) induces several responses, resulting in B-cell activation, proliferation, and differentiation. However, it has been difficult to study these responses due to their dynamic, fast, and transient nature. Here, we attempted to solve this problem by developing a controllable trigger point for BCR and antigen recognition through the construction of a photoactivatable antigen, caged 4-hydroxy-3-nitrophenyl acetyl (caged-NP). This photoactivatable antigen system in combination with live cell and single molecule imaging techniques enabled us to illuminate the previously unidentified B-cell probing termination behaviors and the precise BCR sorting mechanisms during B-cell activation. B cells in contact with caged-NP exhibited probing behaviors as defined by the unceasing extension of membrane pseudopods in random directions. Further analyses showed that such probing behaviors are cell intrinsic with strict dependence on F-actin remodeling but not on tonic BCR signaling. B-cell probing behaviors were terminated within 4 s after photoactivation, suggesting that this response was sensitive and specific to BCR engagement. The termination of B-cell probing was concomitant with the accumulation response of the BCRs into the BCR microclusters. We also determined the Brownian diffusion coefficient of BCRs from the same B cells before and after BCR engagement. The analysis of temporally segregated single molecule images of both BCR and major histocompatibility complex class I (MHC-I) demonstrated that antigen binding induced trapping of BCRs into the BCR microclusters is a fundamental mechanism for B cells to acquire antigens.

B-Cell Activation by Helper T-Cell Membranes

1994 ◽  
Vol 14 (3-4) ◽  
pp. 221-238 ◽  
Author(s):  
Marilyn R. Kehry ◽  
Philip D. Hodgkin
Keyword(s):  
T Cell ◽  
B Cell ◽  
Cell Membranes ◽  
Cell Activation ◽  
B Cell Activation ◽  
Helper T Cell
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