The differential expression of chemokine receptors may be an important mechanism for the regulation of T cell migration. To test this, we examined the expression and function of the monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-8 receptors on various populations of T cells. Using a simple and reliable transendothelial chemotaxis assay, both MCP-1 and IL-8 were shown to be chemotactic for subsets of blood T cells, although the relative response varied from donor to donor. To examine receptor expression and correlate it with chemotaxis of T cell subsets, monoclonal antibodies (mAb) to the receptors were produced by immunizing mice either with synthetic peptides (MCP-1 receptor), or with receptor transfectants (IL-8 receptors A and B). A flow cytometric analysis of blood T cells with an anti-MCP-1 receptor mAb revealed low expression on the CD26(hi) subset and undetectable expression on other T cells. Staining of T cells with anti-IL-8RA and anti-IL-8RB showed much higher levels of expression, but only on a subset of CD3+ cells which were CD8+ and CD56+. That IL-8 and MCP-1 attracted distinct subsets of T cells was best illustrated using the CD26 marker, since IL-8R+ T cells were CD26-, whereas T cells expressing detectable MCP-1R or which responded to MCP-1 in chemotaxis assays were CD26(hi). T cells activated in vitro with anti-CD3 up-regulated expression of the MCP-1 receptor, but not the IL-8 receptors, and were attracted to MCP-1 much more efficiently than resting T cells. These results show that there is a clear distinction between the IL-8- and MCP-1-responsive T cell populations and that chemokine receptor expression on T cells may be regulated with respect to lineage as well as cellular activation.
- Monocyte chemoattractant protein