Article

A Critical Role for OX40 in T Cell–mediated Immunopathology during Lung Viral Infection

Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AZ, United Kingdom.
Journal of Experimental Medicine (Impact Factor: 12.52). 10/2003; 198(8):1237-42. DOI: 10.1084/jem.20030351
Source: PubMed

ABSTRACT

Respiratory infections are the third leading cause of death worldwide. Illness is caused by pathogen replication and disruption of airway homeostasis by excessive expansion of cell numbers. One strategy to prevent lung immune-mediated damage involves reducing the cellular burden. To date, antiinflammatory strategies have affected both antigen-specific and naive immune repertoires. Here we report a novel form of immune intervention that specifically targets recently activated T cells alone. OX40 (CD134) is absent on naive T cells but up-regulated 1-2 d after antigen activation. OX40-immunoglobulin fusion proteins block the interaction of OX40 with its ligand on antigen-presenting cells and eliminate weight loss and cachexia without preventing virus clearance. Reduced proliferation and enhanced apoptosis of lung cells accompanied the improved clinical phenotype. Manipulation of this late costimulatory pathway has clear therapeutic potential for the treatment of dysregulated lung immune responses.

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    • "Even though the PCN treatment did alter pulmonary micro-architecture by inducing iBALT structures and was able to elicit an influx of leukocytes into the airways, these changes to the immune environment of the lung were of no apparent consequence to the well being of the mice. In fact, our results suggest that the PCN-treatment prior to infection is associated with an amelioration of the often excessive inflammatory responses that are seen during the resolution of pulmonary viral infections [16] as well as airway hyperresponsiveness and inflammation associated with asthma. Interestingly, the alterations to the immune environment of the lung in response to the PCN treatment had no effect upon the resolution of pulmonary bacterial infections. "
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    ABSTRACT: Destruction of the architectural and subsequently the functional integrity of the lung following pulmonary viral infections is attributable to both the extent of pathogen replication and to the host-generated inflammation associated with the recruitment of immune responses. The presence of antigenically disparate pulmonary viruses and the emergence of novel viruses assures the recurrence of lung damage with infection and resolution of each primary viral infection. Thus, there is a need to develop safe broad spectrum immunoprophylactic strategies capable of enhancing protective immune responses in the lung but which limits immune-mediated lung damage. The immunoprophylactic strategy described here utilizes a protein cage nanoparticle (PCN) to significantly accelerate clearance of diverse respiratory viruses after primary infection and also results in a host immune response that causes less lung damage.
    Full-text · Article · Sep 2009 · PLoS ONE
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    • "This study suggests that CD8 + T cells may cause tissue injury in lungs by producing proinflammatory mediators (Small et al., 2001). In a study of OX40 role in T-cell-mediated immunopathology in influenza-infected mice, the blocking of OX40/OX40L ameliorated influenza-driven T cell immunopathology in lungs by reduced inflammatory responses and enhanced apoptosis (Humphreys et al., 2003). On the basis of our findings in the pig model system, we hypothesize that the higher mortality rate caused by human H3N2 influenza viruses in elderly patients is due to the high induction of TNF-a in the respiratory tract. "
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    ABSTRACT: Influenza viruses are reported to infect mainly the respiratory tract epithelium of hosts. Our studies in a pig model show that influenza A viruses infect alveolar macrophages that constitutively reside in the respiratory tract, without causing apoptosis. Tumor necrosis factor alpha was the inflammatory cytokine most highly induced in these macrophages. In vivo, alveolar macrophages infected with human H3N2 influenza virus showed greater expression of tumor necrosis factor alpha than did alveolar macrophages infected with human H1N1 influenza virus. Induction of specific inflammatory cytokine such as TNF-alpha is a polygenic trait that involves the HA and NA genes. Markedly elevated expression of tumor necrosis factor alpha may be responsible for the high mortality rate caused by H3N2 influenza virus infection in elderly patients.
    Preview · Article · Dec 2004 · Virology
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