HUMORAL IMMUNE-RESPONSES AND CYTOMEGALOVIRUS EXCRETION IN CHILDREN WITH ASYMPTOMATIC INFECTION

Forty-two seropositive children aged 3 to 5 years attending a kinderga rten were followed up for 1 year in order to examine the relationship between humoral immunity and cytomegalovirus (CMV) excretion status. A nti-CMV antibodies were measured at the beginning and end of the study by enzyme-linked immunosorbent assay, neutralizing antibody test, and immunoblot techniques. Among these children, 32 persistently shed vir us in urine, 2 intermittently shed CMV, and 4 experienced reactivation during the study. Virus was never isolated from 4 seropositive childr en. The level of anti-CMV IgG antibody in seropositive children who re mained nonshedders was significantly higher than in children who shed virus during follow-up. On immunoblots, all seropositive nonshedders r eacted to a CMV-specific 65 kD antigen, whereas most shedders (80%) di d not. These findings suggest that humoral immunity plays a role in co ntrolling persistent CMV infection in children with asymptomatic infec tion. However, the humoral immunity measured by the neutralizing test and the presence of antibodies against CMV-specific envelope antigens (116 kD/55 kD) apparently play a limited role in modifying persistent excretion and regulating reactivation of latent CMV. Immune evasion by CMV to block these antigens may explain these results. (C) 1994 Wiley -Liss, Inc.