The worm and the virus

In it, Jamal Khalife and colleagues describe the unexpected discovery that one of the surface antigens of the helminth worm Schistosoma mansoni contains an epitope that is identical to one of the regulatory proteins of the human immunodeficiency virus HIV-1. The schistosome antigen described by Khalife et al.' is apparently worm-derived, and is a glycoprotein of relative molecular mass 170,000 (Mr, 170K) which appears on the surface of the invading larval schistosome after about three days, while it is still in the skin, and persists into the adult stage. Schistosoma mansoni infections induce the production of a number of cytokines including interleukin-1, interferon-у and tumour necrosis factor, but intcrleukin-1 and tumour necrosis factor stimulate HIV-1 enhancers and thus act as cofactors in AIDS·.