New technology could keep flu viruses from mutating during vaccine production

A joint research project between American and Japanese interests has yielded a new technology that could ease development of H3N2 flu vaccines, by attacking one of their most common causes of concern: mutation during the development process.

Such mutations cause mismatches between the seasonal viruses health agencies are trying to ward off and the vaccines they actually choose to do so. The less like the flu the vaccine is, the less the human immune system is prepared and able to recognize that flu when it attempts to infect.

The new technology created by the University of Wisconsin-Madison’s Yoshihiro Kawaoka and the team have created a new cell line to cut down on this. Unlike many flu vaccines, H3N2 vaccines tend to be grown in modified Madin-Darby canine kidney (MDCK) cells, known as AX4. Kawaoka’s latest creation essentially takes those alterations a step further, making cells that better reflect the human upper respiratory tract. They are currently being tested for effectiveness against circulating strains and for development of cell-based flu vaccines.

“The NIH (National Institutes of Health) is interested in using this new cell line to make H3N2 human challenge strains since these recent H3N2 viruses do not grow well in existing cell lines,” Kawaoka, a professor of pathobiological sciences at the UW-Madison School of Veterinary Medicine, said.

The new cells have been dubbed hCK cells. They have thus far been shown to be much less likely to mutate in regions of the virus critical to its vaccine functionality.

“hCK cells are more than 100-fold better for growing human H3N2 viruses than AX4 cells,” Kawaoka said. “This finding is quite important in both public health and in vaccine production.”

Findings were published in Nature Microbiology. The Wisconsin Alumni Research Foundation has already filed for a patent.