Title:Nasal Vaccines Against Hepatitis B: An Update
VOLUME: 16 ISSUE: 10
Author(s):Mariana S. Almeida and Olga Borges
Affiliation:Faculty of Pharmacy, University of Coimbra, Polo das Ciencias da Saude Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
Keywords:Nasal administration, hepatitis B vaccine, adjuvants, immunopotentiators.
Abstract:After several decades of immunization against hepatitis B virus, the question still remains
whether a new vaccine could avoid the limitations of the current vaccine similar to those associated
with its injectable form or ineffectiveness on chronic hepatitis B disease. A hypothesis to overcome
first limitation is the development of an intranasal vaccine, self-administered, able to achieve not only
systemic immunity, but also sIgA on the vaginal mucosa which would be a great advantage to prevent
the sexually transmitted disease cases. Injectable hepatitis B vaccines that are already available in the market led to
achieving protection mainly through a strong antibody-mediated response. For chronic hepatitis, a strong cellular immune
response would also be required. The aim of this review is to give an overview of the work done in recent years, with the
objective of developing a vaccine that can be administered by intranasal route. A discussion of the leading studies is presented,
focusing not only on potential antigens, but also on promising adjuvants for the hepatitis B antigen. The results of
the immune response generated with different formulations are summarized in tables. It is important to note that almost all
studies claimed the induction of specific mucosal immune response (sIgA) and a balanced cellular and humoral Th1/Th2
or a Th1-type immune response. The further evaluation of these formulations, using a laboratory animal model of viral
hepatitis B, would allow scientific community to conclude about the utility of these new adjuvants, particularly on a combined
immunotherapy strategy for chronic hepatitis B.
