"Team Human" and still more on saluviruses

Reuters at ABC: We are not entirely human, germ gene experts argue

"We are somehow like an amalgam, a mix of bacteria and human cells. There are some estimates that say 90 percent of the cells on our body are actually bacteria," Steven Gill, a molecular biologist formerly at TIGR and now at the State University of New York in Buffalo, said in a telephone interview.

We might better think of ourselves as "team human": a flotilla of life teeming with many other species.

A few years ago I suggested the term saluvirus for beneficial viruses, expecially those naturally-occurring. Slate has an interesting article on what were probably the first-discovered saluviruses: bacteriophages, viruses which kill bacteria.

Daria Vaisman at Slate: The Soviet method for attacking infection

The word phage comes from the Greek "to eat." A phage contains genetic material that gets injected into a virus's host. Whereas "bad" viruses infect healthy cells, phages target specific bacteria that then explode. At Eliava [phage research institue in former Soviet Georgia], phages are produced as a liquid that can be drunk or injected intravenously, as pills, or as phage-containing patches for wounds. Though few published articles in Western journals report positive clinical trials—most of the recent long-term research on phages comes out of the Soviet Union—some Western scientists say that phages are safe and that they work. "There is no evidence that phage is harmful in any way," says Nick Mann, a biology professor at the University of Warwick in England and co-director of phage R&D company Novolytics.

I remember immediately thinking when I first learned about bacteriophages in high school biology that they could be a useful against harmful bacteria. I don't recall our curriculum addressing that possibility.

An exicting part of the article is the prospect of custom phages for any bacterial strain, and constantly updated phage mixes much like constantly-updated flu vaccines. But US medical regulation would throw a monkey-wrench into such dynamic/active medicine:

There are two ways that phages are currently used in the former Soviet Union, and both pose problems from the point of view of the Food and Drug Administration. At the Tbilisi phage center, phages are personalized: You send your bacterial sample to the lab, and it's either matched up with an existing phage or a phage is cultured just for you. In the United States, by contrast, drugs are mass produced, which makes it easier for the FDA to regulate them.

Phages are also sold over-the-counter in Georgia. People take the popular mixture piobacteriophage, for example, to fight off common infections including staph and strep. These phage mixtures are updated regularly so they can attack newly emerging bacterial strains. In the United States, the FDA would want the phages in each new concoction to be gene sequenced, because regulations require every component of a drug to be identified. To do so would entail prohibitively expensive and lengthy clinical trials.

There is some hope for Americans unable to travel to Georgia: "Phages might be offered someday at clinics on Native American reservations, as a casinolike quirk of legislative autonomy."

One step beyond culturing phages from natural stocks would be designing synthetic disease-specific viruses -- and it turns out that's not just appropriate for bacterial disease, but cancer:
New Scientist: Engineered virus thwarts ovarian cancer in mice

Bartlett’s team created a modified vaccinia virus that would target and kill cancer cells. They did this by removing genes in the virus that help it to produce a growth protein. This means that the virus survives best in cancer cells that can supply it with large quantities of this growth protein, as opposed to non-cancerous cells that only produce very small amounts.

The vaccinia virus was also engineered to carry a gene for an enzyme called cytosine deaminase that causes cell suicide in the cells it infects.

Of the mice given the immediate injection, 90% were still alive 180 days later and showed no signs of tumour growth, says Bartlett.

There are previous reports of naturally-occurring anti-cancer viruses. Perhaps spontaneous remissions from cancer are actually triggered by catching such a natural virus, purely by luck. Anyone enjoying such a fortuitous remission should thus be a prime hunting grounds for new saluviruses.

The healthy should be under the microscope in the search for contagions nearly as often as the sick.
Tags: saluvirus, phages, cancer, fda, medicine, bacteria, disease

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