QIMR Testing an Anti Melanoma Vaccine. (July 21, 2004)

    At the annual Federation of Clinical Immunology Societies and the annual International Union of Immunological Societies, currently being held in Montreal, Nathan Martinez, a research officer in Chris Schmidt's lab at the Queensland Institute of Medical Research (QIMR) reported that the group have produced "personalised" vaccines using dendritic cells (a type of white blood cell)  for each of 43 patients with advanced melanoma by harvesting and concentrating their immune cells. Seven of the 43 responded completely, their tumours shrinking to undetectable levels.

That low response rate is par for the course when it comes to cancer vaccines but in this case Martinez's team decided to examine whether those seven patients shared anything in common. they found that the seven had lower levels of a protein, S100B, compared with those who didn't. S100B is normally held inside cells, but some scientists believe that when tumours grow, healthy cells begin dying and release the protein.

While Martinez speculated that perhaps increased levels of S100B signal a large number of tumour cells (tumour burden) that may make a patient less likely to respond to a vaccine, he also reported that in all of the responders tested so far, i.e. four of seven, cytotoxic T cells from pre-vaccine blood samples could kill cells from that patient's tumour in a petri dish, in contrast to the patients who hadn't been helped by the vaccine.

Science reports, "'I've never seen such a striking correlation," says Lloyd Stoolman, an immunologist at the University of Michigan, Ann Arbor. Although he's sceptical about the long-term use of dendritic cell vaccines, which he thinks may be less effective than other types, he agrees that the ability to predict success in cancer vaccine trials is the 'holy grail' of the field."