A novel and effective intranasal immunization strategy for respiratory syncytial virus

In designing subunit vaccination strategies for respiratory syncytial virus (RSV), immunization by mucosal routes may present a realistic alternative to parenteral administration for inducing protective immune responses. To t his end, we have utilized the BALB/c mouse model and an adjuvant formulatio n containing caprylic/capric glycerides (CCG) and polyoxyethylene-20-sorbit an monolaurate (PS). The intranasal (i.n.) delivery of purified natural F p rotein (3 mu g per vaccine) formulated with CCG-PS resulted in the generati on of statistically heightened serum anti-F protein immunoglobulin G (IgG), IgG(1), IgG(2b), and IgA antibodies. In addition, the presence of locally produced anti-F protein IgA was demonstrated in both vaginal and nasal wash es of vaccinated mice. That production of specific serum and mucosal immuno globulins resulted in functional immune responses was shown in neutralizing antibody assays and protection of mouse lungs against subsequent live viru s challenge. Consequently, we propose a novel vaccine formulation composed of purified natural RSV F protein in CCG-PS as a viable intranasal immunoge n to stimulate anti-RSV immune responses in humans.