Virosomes as Adjuvants in Cancer Immunotherapy

Reto Schumacher, Giulio C. Spagnoli, and Michel Adamina 

Department of Surgery, Institute for Surgical Research and Hospital Management, University of Basel, Basel, Switzerland 

Immunopotentiating reconstituted influenza virosomes (IRTV) are spherical 150-nm sized particles consisting of a phospholipid bilayer in which influenza virus A/Singapore strain-derived hemagglutinin (HA) and neuraminidase (NA) are intercalated. As such, they resemble and mimic the influenza virus envelope. The difference from conventional liposome formulations lies in the inclusion of the viral envelope proteins HA and NA as well as viral phospholipids. Especially, the inclusion of influenza virus HA provides IRIV with delivery and immimogenic capacities. IRTV are licensed for human use as adjuvant in hepatitis A vaccination and as influenza subunit vaccine (1). 

IRIV adjuvance in hepatitis A vaccination has been demonstrated as enhancement of humoral responses (1). There are only few adjuvants licensed for human use and they predominantly enhance humoral immune responses (2-4). In view of chronic viral diseases, infections linked to intracellular pathogens, and cancer immunotherapy, there is a need for appropriate adjuvants that have the capability to enhance cellular immune responses, in particular cytotoxic T-cell (CTL) responses (4,5). Here, we addressed IRIV-elicited immune responses and IRIV capacity to enhance CTL responses. 

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