Human mast cells release Interleukin-8 and induce neutrophil chemotaxis on contact with activated T cells


Yoseph A. Mekori, MD
Department of Medicine B
Meir General Hospital
Kfar-Saba 44281


Background:  Mast cells have recently been shown to control neutrophil recruitment during T-cell mediated cutaneous DTH reaction in vivo through TNF-α and MIP-2, the functional murine analogue of human IL-8. Although the nature of signals transmitted from T cells which activate mast cells has not yet been defined, we hypothesized that a direct cross-talk (i.e. heterotypic adhesion) between these two cell populations exists, as has previously been reported.

Aims:  The present study was aimed at gaining insight into the functional role of mast cell–T cell contact in expression and release of IL-8, and its effect on neutrophil chemotaxis.

Methods:  The IL-8 gene expression was identified by Affymetrix GeneChip arrays, validated by RT-PCR and the protein measured by ELISA. Chemotaxis was evaluated by using a modified Boyden chamber assay.

Results:  Mast cells were found to express and release significantly higher concentrations of IL-8 on incubation with membranes obtained from activated, as compared to resting T cells. Supernatants obtained from these activated mast cells induced significant neutrophil chemotaxis that was inhibited by neutralizing mAb to IL-8.

Conclusions:  Thus, activated T cells, on heterotypic adhesion to mast cells, deliver the necessary signals for the latter to release cytokines and chemokines necessary for cell migration to sites of antigen challenge, thereby facilitating T-cell mediated inflammatory processes.