Thesis (Ph. D.)--University of Virginia, 2007. / Includes bibliographical references. Also available online through Digital Dissertations.

Abstract Respiratory syncytial virus (RSV) infection may be associated with the development of asthma and atopy. The aim of the present study was to investigate this association and the related immunological mechanisms. Seventy-six children admitted to Oulu University Hospital in 1991–1994 for an RSV infection at an age of less than 12 months and healthy controls were called for a visit at the age of 6–10 years. Twenty subjects (26%) had asthma compared with 12 controls (16%) (difference 11%, 95% confidence interval (CI) –3% to 24%). Asthma had been diagnosed significantly earlier in the subjects. Eight per cent of the subjects had at least one positive skin prick test as compared with 43% of the controls (difference –35%, 95% CI –50% to –19%). Serum concentrations of interferon-γ and soluble intercellular adhesion molecule -1 were significantly higher among the subjects than among the controls and among the subjects with asthma or current wheezing than among the corresponding controls. All children born in Finland in 1986–1995 were arranged in birth cohorts by month and year of birth and grouped by exposure to an RSV epidemic at age 0–6 months, resulting in 97 exposed and 23 unexposed cohorts. The proportions of children taking asthma medication or receiving special reimbursement for asthma medication in 1995–2002 were similar in the unexposed and exposed cohorts. Altogether 47 children born between August and November 2001 with a cord blood sample taken were admitted to hospital (n = 26) or seen in an outpatient department (n = 21) for RSV infection before the age of six months. Twenty-eight children had some other respiratory viral infection and 84 children formed a group of healthy controls. High scores on a factor combining the cord blood interleukin-6 and interleukin-8 responses (as derived by factor analysis) were shown in logistic regression analysis to predict hospitalization for RSV infection by comparison with the healthy controls (odds ratio 2.29, 95% CI 1.21 to 4.33). We suggest that RSV does not induce asthma but inborn features of immunity affect the severity of RSV infection and the postinfectious development of asthma.

Thesis (D.P.H.)--University of Michigan.

Dissertation (D.P.H.)--University of Michigan.

Respiratory syncytial virus (RSV) causes a common infection that is associated with a range of respiratory illnesses from common cold-like symptoms to serious lower respiratory tract illnesses such as pneumonia and bronchiolitis. RSV is the single most important cause of serious lower respiratory tract illness in children < 1 year of age. Host innate and acquired immune responses activated following RSV infection have been suspected as contributing to RSV disease. Toll-like receptors (TLRs) activate innate and acquired immunity and are candidates for playing key roles in the host immune response to RSV. Leukocytes express TLRs including TLR2, TLR6, TLR3, TLR4, and TLR7 that can potentially interact with RSV and promote immune responses following infection. Using knockout mice, we have demonstrated that TLR2 and TLR6 signaling in leukocytes can activate innate immunity against RSV by promoting TNF-α, IL-6, CCL2 (MCP-1), and CCL5 (RANTES) production. As previously noted, TLR4 also contributed to cytokine activation (71, 90). Furthermore, we demonstrated that signals generated following TLR2 and TLR6 activation were important for controlling viral replication in vivo. Additionally, TLR2 interactions with RSV promoted neutrophil migration and dendritic cell activation within the lung. Collectively, these studies indicate that TLR2 is involved in RSV recognition and subsequent innate immune activation and may play a role in modulating acquired immune responses through DCs. Despite the fact that RSV is the single most important cause of infant upper respiratory tract disease, there are no licensed vaccines available to prevent RSV disease. We have developed a virus-like particle (VLP) vaccine candidate for RSV. The VLP is composed of the NP and M proteins of Newcastle disease virus (NDV) and a chimera protein containing the cytoplasmic and transmembrane domains of the NDV HN protein and the ectodomain of the human RSV G protein (H/G). BALB/c mice immunized with 10 or 40 μg total VLP-H/G protein by intraperitoneal or intramuscular inoculation stimulated antibody responses to G protein as good as or better than comparable amounts of UV-inactivated RSV. Furthermore, VLP-H/G induced robust CTL responses in vaccinated animals. Immunization with two or even a single dose of these particles resulted in the complete protection of BALB/c mice from RSV replication in the lungs. Upon RSV challenge of VLP-H/G immunized mice, no enhanced pathology in the lungs was observed, although lungs of mice immunized in parallel with formalin-inactivated RSV (FI-RSV) showed the significant pathology that has been previously observed with FI-RSV vaccination. Thus, the VLP-H/G candidate vaccine was immunogenic in BALB/c mice and prevented replication of RSV in murine lungs with no evidence of immunopathology. These data support further development of virus-like particle vaccine candidates for RSV.