PROLONGED PERSISTENCE OF MEASLES VIRUS RNA IS CHARACTERISTIC OF PRIMARY INFECTION DYNAMICS.

Tuesday, 18th of June 2013

[source]Proceedings of the National Academy of Sciences of the United States of America[|source]

Prolonged RNA presence in infected childre for long was associated with high risk of SSPE. This article provides experimental details that show that viral RNA persists in blood, respiratory tract or lymph nodes 4-5 times longer that the infectious virus as part of primary infection dynamics and development of lifelong immunity. More details are available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3443140/pdf/pnas.201211138.pdf

Abstract

Measles virus (MeV) is the poster child for acute infection followed by lifelong immunity. However, recent work shows the presence of MeV RNA in multiple sites for up to 3 months after infection in a proportion of infected children. Here, we use experimental infection of rhesus macaques to show that prolonged RNA presence is characteristic of primary infection. We found that viral RNA persisted in the blood, respiratory tract, or lymph nodes four to five times longer than the infectious virus and that the clearance of MeV RNA from blood happened in three phases: rapid decline coincident with clearance of infectious virus, a rebound phase with increases up to 10-fold, and a phase of slow decrease to undetectable levels. To examine the effect of individual host immune factors on MeV load dynamics further, we developed a mathematical model that expressed viral replication and elimination in terms of the strength of MeV-specific T-cell responses, antibody responses, target cell limitations, and immunosuppressive activity of regulatory T cells. Based on the model, we demonstrate that viral dynamics, although initially regulated by T cells, require antibody to eliminate viral RNA. These results have profound consequences for our view of acute viral infections, the development of prolonged immunity, and, potentially, viral evolution.