[Nasal vaccines]

The nasal route for vaccination offers both mucosal and systemic immunity for the prophylaxis of respiratory diseases. In order to induce maximal protective mucosal immunity, co-administration of mucosal adjuvant is essential. In the present review, we discuss natural pulmonary surfactant and its synthetic compound as safe and effective mucosal adjuvants, particularly for the children. The intranasal administration of influenza hemagglutinin(HA) vaccine with the natural compound or its mimicking synthetic compound induced both anti-HA sIgA and IgG in the airway and in the serum, the efficacy being almost equivalent to cholera toxin. No inflammatory cytokine induction and no inflammatory cell migration were detected in nasal cavity. These data suggest that pulmonary surfactant and its synthetic compound are safe and effective mucosal adjuvants that enhance the protective immunity without incurring a risk of inflammation.