Delivery of cytokines by recombinant virus in early life alters the immune response to adult lung infection.
Respiratory syncytial virus (RSV) is the main cause of bronchiolitis, the major cause of hospitalization of infants. An ideal RSV vaccine would be effective for neonates, but the immune responses of infants differ markedly from those of adults, often showing a bias toward T-helper 2 (Th2) responses and reduced gamma interferon (IFN-gamma) production. We previously developed recombinant RSV vectors expressing IFN-gamma and interleukin-4 (IL-4) that allow us to explore the role of these key Th1 and Th2 cytokines during infection. The aim of the current study was to explore whether an immunomodulation of infant responses could enhance protection. The expression of IFN-gamma by a recombinant RSV vector (RSV/IFN-gamma) attenuated primary viral replication in newborn mice without affecting the development of specific antibody or T-cell responses. Upon challenge, RSV/IFN-gamma mice were protected from the exacerbated disease observed for mice primed with wild-type RSV; however, antiviral immunity was not enhanced. Conversely, the expression of IL-4 by recombinant RSV did not affect virus replication in neonates but greatly enhanced Th2 immune responses upon challenge without affecting weight loss. These studies demonstrate that it is possible to manipulate infant immune responses by using cytokine-expressing recombinant viruses and that neonatal deficiency in IFN-gamma responses may lead to enhanced disease during secondary infection.
Harker
James A
JA
Department of Respiratory Medicine, the Centre for Respiratory Infection and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, National Heart and Lung Institute, Imperial College London, St. Mary's Campus, London W2 1PG, United Kingdom.
Lee
Debbie C P
DC
Yamaguchi
Yuko
Y
Wang
Belinda
B
Bukreyev
Alexander
A
Collins
Peter L
PL
Tregoning
John S
JS
Openshaw
Peter J M
PJ
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001835:Body Weight; D005260:Female; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology*; D008168:Lung / Q000276:immunology* / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D011247:Pregnancy; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D022261:Respiratory Syncytial Virus Vaccines / Q000235:genetics / Q000276:immunology*; D012136:Respiratory Syncytial Viruses / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
D000914:Antibodies, Viral; D022261:Respiratory Syncytial Virus Vaccines; D014614:Vaccines, Synthetic; D007371:Interferon-gamma