Polarity of T cell shape, motility, and sensitivity to antigen

Immunity. 1996 May;4(5):421-30. doi: 10.1016/s1074-7613(00)80409-4.


T cell activation requires contact with APCs. We used optical techniques to demonstrate T cell polarity on the basis of shape, motility, and localized sensitivity to antigen. An intracellular Ca2+ clamp showed that T cell shape and motility are extremely sensitive to changes in [Ca2+]i (Kd = 200 nM), with immobilization and rounding occurring via a calcineurin-independent pathway. Ca2+ dependent immobilization prolonged T cell contact with the antigen-presenting B cell; buffering the [Ca2+]i signal prevented the formation of stable cell pairs. Optical tweezers revealed spatial T cell sensitivity to antigen by controlling placement on the T cell surface of either B cells or alpha-CD3 MAb-coated beads. T cells were 4-fold more sensitive to contact made at the leading edge of the T cell compared with the tail. We conclude that motile T cells are polarized antigen sensors that respond physically to [Ca2+]i signals to stabilize their interaction with APCs.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigen Presentation* / physiology
  • B-Lymphocytes / physiology
  • Calcium / physiology
  • Cell Communication / immunology
  • Cell Line
  • Cell Movement / immunology*
  • Cell Polarity / immunology*
  • Glass
  • Humans
  • Mice
  • Micromanipulation
  • Optics and Photonics
  • Signal Transduction / immunology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / physiology
  • Temperature


  • Calcium