INTRODUCTION: Respiratory syncytial virus (RSV) infection is ubiquitous and leads to severe disease in immunocompromised individuals.
OBJECTIVE: Our goal was to compare RSV infection and inflammation between immunocompetent BALB/c mice and immunodeficient nude mice.
METHODS: Pulmonary viral titers, histology, immunohistochemistry for CD14 and CD56, leukocyte counting, and cytokines were assayed by enzyme-linked immunosorbent assay in bronchoalveolar lavage fluid.
RESULTS: RSV titers peaked on the third day after inoculation in both types of infected mice. Infected nude mice had higher-level and more durative viral replication, more severe pulmonary histopathology, and a larger number of leukocytes in bronchoalveolar lavage fluid than infected BALB/c mice. Infected nude mice displayed more pulmonary (CD14+) macrophages (114.34 ± 20.24 vs 75.46 ± 12.37; P = .05) and (CD56+) natural killer cells (37.87 ± 8.07 vs 11.06 ± 5.37; P = .05) than infected BALB/c mice. RSV infection enhanced production of tumor necrosis factor α, interleukin 12 (IL-12), interferon γ, and IL-10 in both types of mice. Infected nude mice had a higher level of tumor necrosis factor α (40.30 ± 7.34 vs 24.24 ± 9.54; P = .05), IL-12 (83.96 ± 12.32 vs 68.21 ± 7.42; P = .05), and IL-10 (125.01 ± 18.97 vs 77.56 ± 9.01; P = .05) than infected BALB/c mice.
CONCLUSIONS: RSV-infected nude mice are a good model for assessing severe and persistent infection in individuals at high risk. RSV-induced inflammation is not parallel to the immune response of T cells, and macrophages and natural killer cells contribute to severe infection and inflammation of RSV-infected cellular-immunodeficient individuals.
Submitted by Juan Zhou
- Copyright © 2008 by the American Academy of Pediatrics