Mast cell-dependent migration of effector CD8⁺ T cells through production of leukotriene B₄

Speaker: 方宜婷

Commentator: 王崇任 醫師

Date: PM 2:00-3:00; 12/10/2003

Room: 601

Abstract:

        The inflammatory response involves the sequential recruitment of both innate and adaptive elements of the immune system. As an important part of the initiating event, mast cell is activated by the aggregation of the high-affinity IgE receptor, FcєRI, which is expressed on the surface of mast cell. Activated mast cell can release lipid-derived mediators such as leukotriene B₄ (LTB₄) through degranulation (1). In previous studies, functional interplay between mast cells and T cells was indicated when activated mast cells and T cells were in inflamed tissue resulting from rheumatoid arthritis, parasitic infection and allergy or asthma (2). In addition, two subsets of memory T lymphocytes are indicated. The central memory T cells (T_CM) migrate to lymph nodes, whereas effector memory T cells (T_EFF) migrate into peripheral inflamed tissues (3). Therefore, the authors want to know the mechanisms that mediate CD8⁺ T cell recruitment to inflamed tissues. In this study, the authors found that activated mast cells induced chemotaxis of T_EFF but not T_CM cells through production of LTB₄. Furthermore, gene expression analysis showed the substantial increase in the amount of LTB₄ receptor BLT1 mRNA in T_EFF compared with that of T_CM cells. By the inhibition of pertussis toxin, the data indicated that expression of BLT1 might account for the selective migration of T_EFF cells to LTB₄ or activated mast cells. Briefly, these studies demonstrated that LTB₄ released by activated mast cell was a potent chemoattractant for CD8⁺ T_EFF cells and induced CD8⁺ T_EFF cell migration to sites of inflammation (4).

References:

1.      Metcalfe, D.D. et al. Mast cells. Physiol. Rev. 77, 1033-1079 (1997).

2.      Mekori, Y.A. et al. Mast cell-T cell interactions. J. Allergy Clin. Immunol. 104, 517-523 (1996).

3.      Sallusto, F. et al. Two subsets of memory T lymphocytes with distinct homing potentials and effector functions. Nature 401, 708-712 (1999).

4.      Ott, V.L. et al. Mast cell-dependent migration of effector CD8⁺ T cells through production of leukotriene B₄. Nat. Immunol. 4, 974-981 (2003).