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Experimental Vaccine Elicits Robust Response Against Both HIV and Tuberculosis
Clinician researchers in China have developed a vaccine that
acts simultaneously against HIV-1 and M.
tuberculosis (Mtb). An estimated 14 million people worldwide are coinfected
with the two pathogens. The research is published in the May 2012 issue of Clinical and Vaccine Immunology.
The vaccine is composed of antigens from both pathogens. The
team, led by Sidong Xiong of Fudan University, Shanghai, incorporated four Mtb
epitopes (the part of an antigen that is recognized by the immune system) into
a backbone composed of HIV-1 p24 protein, a protein that is known to produce
protective immunity against HIV-1. The logic of this construction: many
epitopes are short peptides, with poor immunogenicity unless they are
introduced into a carrier protein—which in this case was the p24 protein.
The vaccine induced cellular immune responses to both
pathogens, in which immune system cells including macrophages search out and
destroy pathogens; and humoral immune response against HIV-1, in which the
immune system produces antibodies against the pathogen. The vaccine was tested
in a mouse model.
Tuberculosis is one of the leading causes of death worldwide;
third, after hepatitis C and then HIV/AIDS among infectious diseases, according
to the World Health Organization (WHO). An estimated 2 billion—28 percent of
the world’s population—are infected with M.
tuberculosis, but most of these infections are latent. However, HIV
infection is the strongest risk factor for the progression of latent
tuberculosis infection to active TB. And
TB is the direct cause of death in about one quarter of all deaths among people
with HIV/AIDS, according to the WHO.
(X. Li, W. Xu, and S. Xiong, 2012. A novel tuberculosis DNA
vaccine in an HIV-1 p24 protein backbone confers protection against Mycobacterium tuberculosis and
simultaneously elicits robust humoral and cellular responses to HIV-1. Clin.
Vac. Immunol. 19:723-730.)