050 - Propagation of Rabies Virus in Tissue Culture and the Successful Use of Culture Virus as an Antirabic Vaccine

This was a short report about some researchers, Leslie Webster and A.D. Clow, who found a way to grow rabies virus in tissue culture. Previously, it had only been propagated in lab animals or isolated from wild/feral animals. Being able to grow it in a lab, one way or another, is important because that's how to make the vaccine to prevent or treat this almost-always-fatal disease.

As I have discussed in previous posts (040 and 043), injecting someone with animal brain tissue as a vaccine against rabies often worked, but the downside was that occasionally it induced an immune response against the vaccinee's own central nervous system, especially the myelin component, which could cause serious problems.

Webster and Clow claim that their method, described in this study, should be less risky in this regard, because it doesn't contain so much extra brain tissue. They didn't test this, though, at least not here, so I'm not sure how much to believe it, and here's part of why:

The method for growing rabies in culture that they devised involves keeping cells from mouse brains alive in monkey serum (the liquid components of blood), and inoculating that with virus. So it still involves mouse brain material. Probably not nearly as much though, or as many different kinds, so they could be right.

Anyway, it does seem like a good alternative to propagating the virus in whole animals. They report that they passed the virus through this culture over a series of 16 transfers, and it still worked fine as a vaccine or as a pathogen in animals at the end. If the virus weren't growing, each transfer would have diluted it more and more, until there was hardly any left after six transfers. So it seems clear that it's actually growing.

And they tried immunizing mice and ferrets with it, injecting it into their body cavities, and it protected all of them from infection with virulent forms of the virus even when injected directly into the brain. Immunization by virus under the skin didn't really work though, at least in ferrets. But the immunizing power of this tissue culture virus seemed about as strong as that taken from animal brains. So it's pretty promising, perhaps.

Citation: Webster, L. T. & Clow, A. D. Propagation of Rabies Virus in Tissue Culture and the Successful Use of Culture Virus as an Antirabic Vaccine. Science 84, 487–488 (1936).