Differential gene expression by integrin β7+ and β7- memory T helper cells

RNA was prepared from β7+ and β7- CD4+ CD45RA- blood T cells from nine normal human subjects and analyzed using oligonucleotide microarrays. Of 21357 genes represented on the arrays, 16 were more highly expressed in β7+ cells and 18 were more highly expressed in β7- cells (≥1.5 fold difference and adjusted P < 0.05). Several of the differentially expressed transcripts encode proteins with established or putative roles in lymphocyte adhesion and chemotaxis, including the chemokine receptors CCR9 and CCR10, the integrin α4 subunit, L-selectin, KLRB1 (CD161), NT5E (CD73), LGALS1 and LGALS2 (galectin-1 and -2), and RGS1. Flow cytometry was used to determine whether differences in levels of transcripts encoding cell surface proteins were associated with differential expression of those proteins. Using this approach, we found that surface expression of KLRB1, LAIR1, and NT5E proteins was higher on β7+ memory/effector T cells than on β7- cells.Memory/effector T cells that express integrin β7 have a distinct pattern of expression of a set of gene transcripts. Several of these molecules can affect cell adhesion or chemotaxis and are therefore likely to modulate the complex multistep process that regulates trafficking of CD4+ memory T cell subsets with different homing behaviors.Lymphocyte migration is a multistep process that involves a complex interplay between adhesion molecules and chemokines and their G protein-coupled receptors [1,2]. Na？ve T cells express the adhesion molecule L-selectin, the chemokine receptor CCR7 and other molecules that allow these cells to migrate preferentially to secondary lymphoid organs where they can encounter antigen-presenting cells. When presented with appropriate antigens, these T cells can differentiate into memory T cells. Some memory cells continue to express L-selectin and/or CCR7 and to migrate efficiently to secondary lymphoid organs, whereas others lose expression of these molecules and instead express other molecules that direct m