Activation of systemic and mucosal immune response following nasal administration of liposomes

Adjuvant effects of liposomes on systemic and mucosal immune response were investigated following nasal administration to Balb/c mice. Bovine serum albumin (BSA)-specific serum IgG and salivary IgA levels were significantly elevated when BSA-associated liposomes were administered intranasally twice at 4-week intervals. Systemic immune response was activated only by negatively charged liposomes, while activation of mucosal immune response was independent of liposomal charge. Antigen localization in liposomes affected immune adjuvant effect; the mucosal immune response could be activated only by liposomes to whose surface BSA was attached, but the systemic immune response was activated by both liposomes to which antigens were attached and in which the encapsulating antigens occurred. The results suggest that the contribution of antigen-presenting cells in activation of systemic and mucosal immunity following intranasal administration is different.