Liposome Encapsulated Antigen Shows Promise In Vaccine Delivery.

2001 AUG 15 - (NewsRx.com & NewsRx.net) --

by N.R. Saltmarsh, staff medical writer - Liposome encapsulated antigen can elicit both cell-mediated and humoral immune responses and thus may be an ideal vaccine candidate, according to a new report in the Scandinavian Journal of Immunology.

"Liposomes have been widely used to deliver antigens to the antigen-presenting cells (APCs) and also to modify their immunological behavior in model animals," reported M. Owais and colleagues in India. "We recently demonstrated the potential of yeast lipid liposomes to undergo membrane-membrane fusion with cytoplasmic membrane of the target cells."

Their current experiments showed that antigen encapsulated in yeast lipid liposomes could be simultaneously delivered into both the cytosolic and endosomal processing pathways of APCs and thus could generate both CD4(+) T helper and CD8(+) cytotoxic T cells.

Encapsulating the same antigen in egg phosphatidyl-choline (PC) liposomes, on the other hand, limited access to the cytosolic pathway of major histocompatibility complex (MHC) I-dependent antigen presentation and failed to generate antigen-specific CD8(+) cytotoxic T-cell responses, reported Owais and associates, as did using the antigen in its free form ("Use of liposomes as an immunopotentiating delivery system: In perspective of ...