Cell-mediated immunity in experimental cytomegalovirus infections: a perspective

Treatment of cytomegalovirus (CMV) infections has assumed increasing importance in the care of immunocompromised patients, particularly allograft recipients and patients with symptomatic infection with the human immunodeficiency virus. The crucial role of T cells in the host defense against CMV may be inferred by the expression of life-threatening CMV disease in these restricted patient subpopulations. However, detailed understanding of the pathogenesis of CMV disease in the compromised host is lacking, and the mechanisms by which T cells confer protection are unknown. Insight into the pathogenesis of CMV in these patients is crucial for the development of rational therapeutic strategies. A considerable body of data has been generated to explore the role of T cell-mediated immunity in a number of model viral infections as well as in experimental CMV infections in both normal and immunocompromised mice. This experience will be critically reviewed to clarify the often conflicting observations regarding a protective or, conversely, a pathogenic role for T cells in producing CMV disease.