Human memory T cells express intercellular adhesion molecule‐1 which can be increased by interleukin 2 and interferon‐γ

Abstract

We have shown that low levels of intercellular adhesion molecule‐1 (ICAM‐1) expression can be detected on approximately 40% of the resting peripheral blood T cell population. The ICAM‐1⁺ T cells have the phenotypic markers of memory cells which can be distinguished functionally from naive T cells by their ability to respond rapidly to previously experienced antigen. These cells appear to be in a state of marginal activation in that they also express low levels of the interleukin 2 receptor (Tac antigen) and have increased cell size as compared to the naive T cells. In addition we have shown that the cytokines interleukin 2 and interferon‐γ, both of which are products of activated T cells, are able to increase the expression of ICAM‐1 on T cells. Finally, pretreating T cells with an anti‐ICAM‐1 monoclonal antibody inhibits their response to recall antigens, strongly suggesting a functional role for this protein on the memory T cell.