Using anthrax as a delivery vehicle for vaccines raises nightmare visions. But Avant Immunotherapeutics Inc. believes it has developed an antigen delivery method, called Therapore, that uses the delivery component of the anthrax protein without the toxic portion. The company believes that Therapore could efficiently introduce HIV antigens into the cytosol - the fluid portion of the cell's cytoplasm where most proteins are synthesized - of antigen-presenting cells, where they need to be in order to induce an immune response.

Last week, AVAN (Needham, Mass.) and Harvard University researchers published data, in the Proceedings of the National Academy of Sciences, showing that HIV candidate vaccines containing a modified Bacillus anthrax lethal toxin fused with HIV antigens of up to 500 amino acids was able to induce CD8 T cells in mice. The study also showed constructs of the toxin encoding gag p24 and