Original Article: Experimental Nanomedicine, Immunology
Well-defined and potent liposomal hepatitis B vaccines adjuvanted with
lipophilic MDP derivatives
Vikas Jain, MPharm, Suresh P. Vyas, PhD, Dharmveer V. Kohli, PhD
Drug Delivery Research Laboratory, Department of Pharmaceutical Sciences, Dr. Hari Singh Gour University, Sagar (M.P.), India
Received 1 June 2008; accepted 24 December 2008
The characterization of immunological cascades of the innate immune system activated by invariant molecular structures termed as
pathogen-associated molecular patterns recognized by pattern recognition receptors of macrophages and dendritic cells, have allowed the
elucidation of the mechanisms underlying the immunomodulatory properties of adjuvants. Thus, adjuvant-active lipophilic analogues of N-
acetyl muramyl dipeptide (MDP) were incorporated in liposomal hepatitis B surface antigen (HBsAg) formulations. The immunoreactivity of
the formulations was evaluated by measuring anti-HBs, immunoglobulin G (IgG), and isotype antibody titer and compared with alum-
adsorbed HBsAg formulation. The formulations were also evaluated for cell-mediated immune response by HBsAg-specific proliferation of
splenocytes and simultaneous estimation of cytokines (interleukin-4 [IL-4], interferon-γ [IFN-γ]). Results indicate that the serum IgG and
anti-HBs titer obtained after intramuscular administration of liposomal muramyl tripeptide–phosphatidylethanolamine (MTP-PE) and
liposomal N-acetylmuramyl-l-alanyl-d-isoglutamine–glycerol dipalmitate (MDP-GDP) antigenic formulations were significantly higher. The
incorporation of MTP-PE on the liposomal HBsAg increased the stimulation index (SI) four to five times as compared to plain HBsAg
solution, and it also induced significantly higher Th1 cellular immune response with a predominant IFN-γ level. So it is the novel effective
and potentially safe approach in which liposomes act as delivery vehicles for hepatitis B viral antigen to antigen-presenting cells and is
ornamented with a biological response modifier that could activate these target cells to enhance the antigen presentation to T lymphocytes.
From the Clinical Editor: In this study, adjuvant-active lipophilic analogues on N-acetyl muramyl dipeptide (MDP) were incorporated in
liposomal hepatitis B surface antigen (HBsAg) formulations. The immunoreactivity of the formulations was evaluated and found effective,
leading to a potentially enhanced immune response against the delivered antigen.
© 2009 Elsevier Inc. All rights reserved.
Key words: Targeted immunization; MTP-PE; Immunoliposomes
Hepatitis B infection remains a global problem despite the
effectiveness of the hepatitis B virus (HBV) vaccine in
preventing infection. Approximately 350 million people
around the world are persistently infected by HBV.
adult patients infected with HBV, about 95% are suffering
from acute infection and 55% have developed chronic
diseases with persistent viremia and liver inflammation.
Of greater concern is that the majority of these individuals
may develop cirrhosis and hepatocellular carcinoma later in
life as a result of chronic hepatitis.
Currently the only
therapy for chronic hepatitis is systemic treatment with
Therapeutic alternatives in the form
of nucleotide analogues like lamivudine are also available.
However, short-term treatment leads to rapid relapse of
disease, and long-term treatment often results in the selection
of resistant viral variants.
Thus, vaccination strategy is
thought to be the only medical measure that can reduce the
incidence of HBV infection and related ailments.
immunogenic vaccines based on the inclusion of adjuvant
moieties within an antigen delivery system may represent a
rational design approach to the development of more
Antigen delivery systems such as
liposomes have been shown to be versatile in their ability
to incorporate a diverse range of antigens. The possibility for
the use of co-adjuvants in these systems further enhances
their potential as potent carrier constructs for maximization
of immune responses.
One of the adjuvants that has been
successfully incorporated into liposomes is N-acetyl mur-
amyl dipeptide (MDP), a component of bacterial cell walls.
Available online at www.sciencedirect.com
Nanomedicine: Nanotechnology, Biology, and Medicine 5 (2009) 334 – 344
Corresponding author. Department of Pharmaceutical Sciences,
Dr. Hari Singh Gour University, Sagar (M.P.) 470003, India.
E-mail address: firstname.lastname@example.org (D.V. Kohli).
1549-9634/$ - see front matter © 2009 Elsevier Inc. All rights reserved.
Please cite this article as: V. Jain, S.P. Vyas, D.V. Kohli, Well-defined and potent liposomal hepatitis B vaccines adjuvanted with lipophilic MDP
derivatives. Nanomedicine: NBM 2009;5:334-344, doi:10.1016/j.nano.2008.12.004