TOPICAL IMMUNOPROPHYLAXIS OF RESPIRATORY SYNCYTIAL VIRUS (RSV)-CHALLENGED MICE WITH RSV-SPECIFIC IMMUNE GLOBULIN

The modulatory effects of passive antibody on viral replication, illne ss, and immunity were investigated in a murine model of respiratory sy ncytial virus (RSV) infection. Nasally administered RSV-specific immun e globulin (RSVIG) given prophylactically in a large volume (100 mu L) reduced illness and RSV replication in lung after primary challenge. However, passive antibody treatment diminished the host antibody respo nse to primary RSV infection. This resulted in greater susceptibility to reinfection and an alteration in the composition of the immune resp onse after rechallenge. RSV infection of lung during primary infection was necessary for complete protection of lung from RSV rechallenge. N asal infection alone during primary infection was not sufficient to pr otect against RSV rechallenge of lung, suggesting that the immune resp onses in the murine system are compartmentalized. The influence of com partmentalized immunity and modulation of immune responses will be imp ortant considerations as new approaches for topical immunoprophylaxis of RSV are developed.