Influenza virosomes as a vaccine adjuvant and carrier system

Abstract

Influenza virosomes have been used for more than 10 years in commercial vaccines. The technology has been further developed as a carrier and adjuvant system for subunit vaccines, in particular for synthetic peptides. The extensive amount of preclinical and clinical data supports the notion that influenza virosomes represent a platform technology that ensures robust and long-lasting immune responses against subunit antigens with an excellent safety profile. Structurally and functionally, virosomes are enveloped virus-like particles, although they are assembled in vitro. This unique feature ensures a tight control of their composition and at the same time provides the flexibility to adapt the particle to various types of antigens. The mode of action of virosomes is complex and includes carrier as well as immune-stimulatory functions.

Differential Approaches for Vaccination from Childhood to Old Age

“…At both age extremes, Th1 responses and sufficient cytotoxicity of lymphocytes have to be improved, e.g. by use of adjuvants [42,44,45,46], by concomitant vaccination with other vaccines [22], by change in antigen concentrations, e.g. high-dose vaccines for influenza [40] or zoster [39] in the elderly, or implementation of other dose intervals [15,20].…”

“…A very long experience exists with adjuvants in seasonal influenza vaccination, such as MF59 [44,45] and virosomes [46], increasing efficacy of influenza vaccination by inducing specific CD4+ T cell responses, strong and long-lasting memory T and B cell responses and by broadening the immune responses beyond the influenza strains included in the actual vaccine [44] with a favorable outcome also in small children [45]. …”

On vaccine's adjuvants and autoimmunity: Current evidence and future perspectives

“…Virosomes are spherical lipid vesicles that include the functional viral glycoproteins haemagglutinin and neuraminidase from influenza [77] and can be regarded as uni-lamellar liposomes carrying the spike proteins of influenza virus on their surface [78].…”

“…The influenza HA antigen targets the virosomes to APCs, which engulf it by endocytosis and present the antigens to T cells after proteolytic degradation. Pre-existing immunity against influenza may represent another important determinant for the immunostimulating effect of virosomes [77].…”

VHSV G glycoprotein major determinants implicated in triggering the host type I IFN antiviral response as DNA vaccine molecular adjuvants

“…Recent studies have showed that virus-related products such as the defective interfering (DI) RNA produced by the Sendai virus strain Cantell [19] or influenza virosomes [20] can efficiently work as viral vaccine adjuvants. We recently identified two linear determinants of gpG VHSV (peptides p31 and p33) implicated in triggering a cell antiviral response mediated by type I IFN [21].…”