T cell therapy of human CMV and EBV infection in immunocompromised hosts.

Acute virus infections in normal hosts are typically controlled by the development of a host immune response that includes MHC-restricted virus-specific T cells. Many viruses have developed methods to evade T cell recognition to facilitate initial infection and the establishment of a persistent infection in the host. Human cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are ubiquitous human pathogens that utilise novel strategies to evade immune elimination. Despite these evasion methods, CD4(+) and CD8(+) T cells expressing alphabeta T cell receptors have been shown to play a pivotal role in controlling initial infection and in maintaining CMV and EBV in a latent state. However, in settings of iatrogenic or acquired T cell deficiency, primary infection or reactivation of CMV and EBV frequently progresses to cause life threatening disease. In this article the role of MHC-restricted CD8(+) and CD4(+) T cell responses in controlling CMV and EBV infections in healthy individuals and the development of novel strategies to restore protective T cell immunity to deficient hosts by the adoptive transfer of virus-specific T cells is reviewed. Copyright 1997 John Wiley & Sons, Ltd.