Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection and deaths in infants. Since the failure of formalin-inactivated RSV (FI-RSV) due to vaccine-enhanced pulmonary eosinophilia and pneumonia during 1960s, there is no licensed vaccine against RSV. In this study, we analyzed immune cell phenotypes and cytokines in bronchoalveolar lavage fluids (BALF) from mice immunized with FI-RSV, live RSV, or F plasmid and virus-like particles (VLP) containing RSV F and G glycoproteins (FFG VLP) at day 5 post RSV challenge. FI-RSV immunized mice showed severe eosinophilia, high levels of CD11b+ cells as well as IFN-gamma and IL-4 secreting CD4 T cells locally and systemically. Mice pre-immunized with live RSV showed no severe pulmonary eosinophilia, similar levels of IFN-gamma secreting CD4 and CD8 T cells, and low levels of IL-4 secreting cells. Mice immunized with FFG VLPs displayed no eosinophilia, relatively a low ratio of CD4/CD8 T cells secreting IFN-gamma, and no systemic cytokines. All 3 types of RSV vaccines were effective in clearing lung viral loads. Taken together, these results suggest no correlation between lung RSV clearance and inflammatory pulmonary disease, and that FFG VLP can be a promising RSV vaccine candidate conferring protection without lung disease.
- Copyright © 2013 by The American Association of Immunologists, Inc.