Mucosal immunoadjuvant activity of liposomes: induction of systemic IgG and secretory IgA responses in XXXX by intranasal immunization with an @entity683 subunit vaccine and coadministered liposomes.

@entity17521 @entity19 @entity1298 @entity2434 @entity683 @entity281 @entity165
This paper reports on a novel immunoadjuvant activity of liposomes. An @entity683 subunit preparation, containing the isolated viral surface antigens, was incorporated in a liposomal formulation. Administration of this vaccine to @entity19 via the intranasal (i.n.) route resulted in a stimulated serum IgG response relative to the response to i.n. immunization with the antigen alone. In addition, the liposomal vaccine induced a secretory IgA (sIgA) response in the mucosa of the lungs and nasal cavity. Both serum IgG and sIgA responses persisted up to at least 21 weeks postimmunization. Immune stimulation was observed with negatively charged liposomes consisting of @entity2434 (PC), @entity165 and @entity17521 ( @entity1298 ), but not with zwitterionic liposomes, consisting of PC and @entity165 alone. Remarkably, for stimulation of serum IgG responses and induction of an sIgA response, liposomes could be simply mixed with the antigen. Moreover, i.n. administration of empty liposomes up to 48 h prior to i.n. immunization with the subunit antigen also resulted in immune stimulation, indicating that the liposomes did not exert their adjuvant effect by acting as a carrier for the antigen. The liposomal vaccine conferred protection against @entity281 . It is concluded that liposomes, administered i.n., provide a promising adjuvant system for stimulation of antibody responses in general, and mucosal sIgA responses in particular.
