Antiviral Activities of a Human Monoclonal Antibody against Human Cytomegalovirus

Abstract

Human cytomegalovirus (CMV) causes infections ranging from subclinical illness to severe disease with significant morbidity and mortality in immunocompromised hosts such as recipients of organ or bone marrow transplants (1, 2), patients with acquired immunodeficiency syndrome (3), and newborn babies (4). The immune mechanisms which restrict human CMV infections are thought to involve cellular immune response more than humoral immune response. This is indicated by the facts that patients with deficiencies of cell-mediated immunity are at high risk of CMV disease and such patients develop severe CMV disease despite the presence of antibodies in their serum (5). Nevertheless, there is some evidence to suggest that humoral antibodies are effective in preventing serious consequences of CMV infection. Passive immunization with human immunoglobulin, especially with a high titer against CMV, has been shown to reduce the incidence of symptomatic CMV infection in transplant recipients (6, 7). Preexisting maternal antibodies also provide some protection against severe CMV infection in newborns (8). These findings suggest that a monoclonal antibody (MAb) of very high titer would provide a potent protective effect against this disease.