Environmental Engineering Reference
In-Depth Information
DNA vaccine packaging offers a promising strategy to cross various physiological
barriers for eliciting a definite protective mucosal
immunity via intranasal
administration [
9
].
Hydrophilic and hydrophobic fluorescent dyes as model drugs tagged with
liposomes are found to be more effective in penetrating depth into the hair follicles,
as compared to a standard, nonliposomal formulation [
33
].
The effective vaccination against
Leishmania major
infection was done by
1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) nanoliposomes complexed
with immune adjuvant for soluble Leishmania antigens (SLA) for higher encapsu-
lation efficiency of SLA and low parasitic burden. The intrinsic adjuvanticity of the
DOTAP-nanoliposomes as an antigen delivery system induces appropriate Th1
type of immune response and protection against
L. major
infection as compared
to free SLA or free liposome [
34
].
Intravenous, intradermal, and eventually subcutaneous injections of liposomes
provide an important agent in delivery of mRNA for vaccination. Liposomes
containing mRNA of influenza virus nucleoprotein induce anti-influenza cytotoxic
T lymphocytes, activating the T cell mediated immune responses in the host
identical to those obtained in vivo with infectious virus. Liposomes combined
with polymers to form lipopolyplexes were also useful for vaccination with nucleic
acids [
9
,
32
].
Many studies revealed the delivery of self-amplifying RNA via liposomes for
gene therapy. CLP has shown efficient gene transfection and biocompatibility in
in vitro studies, and has a few therapeutic applications in clinical trials, but
critically its usage is limited for its in vivo instability. Hydrophobic CHOL,
nonionic surfactants, or polyethylene glycol (PEG) has been widely used to
increase the in vivo stability of CLP. However, Liposome/DNA complexes,
injected intravenously sometimes form large aggregates with blood cells and
these aggregates get entrapped in the lung capillary bed [
9
,
32
].
Liposomes are promising tool for nonviral gene delivery. Several liposome-
based vectors were used as vaccines and assayed in clinical trials. Allovectin-7
®
(Vical, San Diego, CA, USA), a pDNA carrying
β
2-microglobulin genes and major
histocompatibility complex, class 1, B (HLA-B) genes were complexed with
1,2-dimyristyloxy-propyl-3-dimethyl-hydroxy ethyl ammoniumbromide/dioleoyl-
phosphatidyl ethanolamine (DMRIE/DOPE) liposomes, for its assessment for
safety and efficacy in Phase I and II clinical trials [
5
-
7
,
9
,
32
].
9.1.4 Liposomal Nanomedicine and Disease Targeting
Liposomes, at present, are widely applied as drug carriers in clinic, since the first
liposomal pharmaceutical product, Doxil (formulation of DOX), received FDA
approval
in 1995. Till now, varied important
types of liposomes,
like CLP
