Biology Reference
In-Depth Information
protection against challenge infection to rhesus macaques. However,
for the development of an effective vaccine, it has been a challenge to
induce protective antibodies of similar specificities by vaccination.
Therefore, efforts are being made by different groups to design an
Env immunogen that may be more effective compared to the existing
immunogens in inducing potent neutralizing and protective anti-
body responses by: i) optimizing existing Env structure to enhance
the exposure of functional epitopes to focus the responses to these
epitopes; ii) obtaining structural information on HIV Env, and using
this information for structure-based novel immunogen design; and
iii) identifying novel functional epitopes, and designing strategies to
incorporate them in potential vaccines. Once potent HIV Env struc-
tures have been identified, their effectiveness may be enhanced through
the use of adjuvants, delivery systems, and prime and boost strategies
to improve the quality and magnitude of neutralizing responses.
Introduction
AIDS continues to be a major health problem throughout the world,
with approximately 40 million cases and 20 million deaths recorded
so far. In certain parts of the world, such as Sub-Saharan Africa, the
prevalence of human immunodeficiency virus (HIV) in the popula-
tion is estimated to be as high as 35%.
1
If current infection rates and
the absence of affordable treatments continue, 60% of the current
adolescent population in that region will not live to the age of 60.
1
In
the United States today, an estimated 950,000 individuals are living
with HIV, and 40,000 to 80,000 new infections occur each year.
1
Moreover, the situation is continuously deteriorating as a result of the
rapid emergence of drug resistance against most of the effective anti-
virals. Therefore, there is an urgent need for an effective anti-HIV
vaccine that may be used either alone as a prophylactic vaccine or in
conjunction with anti-viral drugs as a therapeutic treatment.
Based on preclinical and early clinical studies, it was concluded
that neutralizing antibody responses induced by monomeric HIV
Env are not potent enough to protect against the HIV infection.
2,3
Therefore the dogma shifted from the induction of neutralizing
