Vaccine developed for leishmaniasis
A novel DNA vaccine against leishmaniasis has been
developed by researchers at the National Institute of Allergy and Infectious
Diseases, United States. The vaccine targets the saliva of the sand fly
that transmits the Leishmania major parasite rather than the parasite
itself.
Dr Jesus Valenzuela and colleagues identified a
salivary protein, called SP15, that protected mice against infection.
They then developed a DNA vaccine for the protein.
Immunised mice injected with Leishmania major
had a much milder infection than non-immunised mice. The immunised mice
were able to clear the infection whereas the non-immunised mice could
not.
One of the study authors, Dr José Ribeiro, comments:
“People get bitten by infected sand flies all the time without developing
leishmaniasis. It could be that those who develop disease are merely unlucky;
they are bitten by a leishmania-carrying fly before uninfected flies have
had time to naturally immunise them.” He cautions that for the anti-saliva
vaccine to work it might have to be specifically engineered for the different
sand fly species in different regions (Journal of Experimental Medicine
2001;194:331).
Leishmaniasis is a parasitic infection principally
affecting the liver, spleen and skin. Symptoms depend on the site of infection
and include fever, weight loss and hepatomegaly or splenomegaly in visceral
lesihmaniasis, and large skin ulcers in cutaneous leishmaniasis.
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