Chapter

Cell Communication in Nervous and Immune System

Volume 43 of the series Results and Problems in Cell Differentiation pp 199-218

Date:

The Biophysics of T Lymphocyte Activation In Vitro and In Vivo

  • Peter ReichardtAffiliated withJunior Research Group of Immunodynamics, German Research Centre for Biotechnology (GBF)
  • , Matthias GunzerAffiliated withImmunodynamics, German Research Centre for Biotechnology (GBF) Email author 

* Final gross prices may vary according to local VAT.

Get Access

Abstract

T cell activation is crucial for the development of specific immune reactions. It requires physical contact between T cells and antigen-presenting cells (APC). Since these cells are initially located at distinct positions in the body, they have to migrate and find each other within secondary lymphoid organs. After encountering each other both cells have to maintain a close membrane contact sufficiently long to ensure successful signaling. Thus, there is the necessity to temporarily synchronize the motile behavior of these cells. Initially, it had been proposed that during antigen recognition, T cells receive a stop signal and maintain a stable contact with APC for several hours when an appropriate APC has been encountered. However, direct cell observation via time-lapse microscopy in vitro and in vivo has revealed a different picture. While long contacts can be observed, many interactions appear to be very short and sequential despite efficient signaling. Thus, two concepts addressing the biophysics of T cell activation have emerged. The single encounter model proposes that after a period of dynamic searching, a T cell stops to interact with one appropriately presenting APC until signaling is completed. The serial encounter model suggests that T cells are able to collect a series of short signals by different APC until a critical activation threshold is achieved. Future research needs to clarify the relative importance of short and dynamic versus long-lived T cell–APC encounters for the outcome of T cell activation. Furthermore, a thorough understanding of the molecular events underlying the observed complex motility patterns will make these phenomena amenable for intervention, which might result in the identification of new types of immune modulating drugs.

Biophysics Cell–cell interaction DC T cell activation