Anti-malarial assistant

Creating an effective vaccine against an infectious disease is not as simple as activating an immune response. Immune activation can take many forms, not all of which are effective against all pathogens. An adaptive immune response involving cytotoxic T cells (CTL) has been demonstrated to be necessary to effectively prevent malaria, which is caused by the parasite Plasmodium falciparum in humans. Thus a vaccine that results in CTL activation could presumably be effective in protecting against malarial infection. To generate an effective adaptive immune response, a specific antigen is injected along with an adjuvant (traditionally a crude extract that promotes an immune response). Although protective antigens have been defined, a problem in formulating an effective malarial vaccine is that it is difficult to get the immune system to respond by generating long-lasting CTLs in sufficient numbers to these antigens.

In the March 4 issue of The Journal of Experimental Medicine, Moriya Tsuji and colleagues demonstrate that a glycolipid (a-GalCer) originally isolated from marine sponges can serve just such a purpose act as a CTL promoting adjuvant against malaria when used in conjunction with Plasmodium vaccines. a-GalCer interacts with a receptor on a specialized lymphocyte (NKT cell) that bridges two arms of the immune system, innate and adaptive immunity. By co-injecting a-GalCer with various malaria vaccines, such as irradiated sporozoites and recombinant adenoviruses, Tsuji and colleagues were able to enhance long-lasting CTL mediated immunity against a mouse model of malaria infection. The authors discuss how this adjuvant may be an effective tool in generating vaccines against a variety of intracellular microbial pathogens including HIV.

Corresponding author:
Dr. Moriya Tsuji
New York University School of Medicine
Department of Medical and Molecular Parasitology
341 East 25th St.
New York, NY10010
USA
Tel 212 263-6758
Fax 212 263-8116
e-mail moriya.tsuji@med.nyu.edu

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