Dynamics of Blood-Borne CD8 Memory T Cell Migration In Vivo

Immunity, 20, 551-562, 2004

Speaker: 陳煜恬                                 Date: 2004/12/08  15:00~16:00

Commentator: 余俊強 老師                        Place: Room 601

Abstract:

Memory CD8 T cells are a subset of cells that react more quickly and efficient upon secondary infection. Whether these cells came from the progeny of armed-effector cell or originally existence subset remain uncertain. Different from armed-effector CD8 T cells, memory CD8 T cells are found in many tissues outside the inflammation site. Thus, the author took the “blood-borne dynamic pool” theory to describe this phenomenon. They use adoptive transfer and parabiosis system to demonstrate the memory CD8 T cells in this pool can be separated into three groups depending on their migrating capacity. In the nonlymphoid organ, such as lung, liver, the migration equilibrium was rapidly achieved. While in the peritoneal capacity, the migration was delayed but eventually reached equilibrium. And the brain and the intestinal did not reach equilibrium within the times tested. Besides, different homing signal expression, such as integrins α₄β₇, chemokine receptor CCR9 also contributes to this migration pattern. Furthermore, the memory CD8 T cells are still with function through IFNγ secretion and surface LAMPs expression, which express on the cell membrane only when CTL carry out its killing capacity to target cells. In conclusion, memory CD8 T cells form a dynamic pool to ensure complete elimination of pathogen, and its tissue-specific pattern may have important implications for the development of autoimmunity due to molecular mimicry, vaccine development, and current approaches for disease treatment by selectively blocking lymphocyte migration into particular tissues.

References:

1.        Masopust, D., et al. Activated primary and memory CD8 T cells migrate to nonlymphoid tissues regardless of site of activation or tissue of origin. J. Immunol. 172, 4875-4882(2004)

2.        Campbell, J.J., et al. Chemokines in tissue-specific and microenvironment-specific lymphocyte homing. Curr. Opin. Immunol. 12, 336-341(2004)

3.        Kimberly, D., et al. Dynamics of blood-borne CD8 memory T cell migration in vivo. Immunity, 20, 551-562 (2004)