Researchers develop oral vaccine for PRRSV in pigs

By Lee I-chia  /  Staff reporter

Thu, Jul 18, 2013 - Page 3

A research team from National Taiwan University said it has developed the world’s first oral vaccine from transgenic bananas that can reduce the risks of pigs contracting porcine reproductive and respiratory syndrome virus (PRRSV).

The team, led by Huang Pung-ling (黃鵬林), a professor in the Department of Horticulture and Landscape Architecture and on secondment as dean of Chinese Culture Univerisity’s Agriculture College, said PRRSV is a virus that causes reproductive failure in breeding pigs and respiratory tract illness in piglets.

The disease, also known as the blue-ear pig disease or mystery swine disease, can cause serious damage to the swine breeding industry, he said.

Current prevention methods using vaccine made by dead viruses have not been very effective, Huang said.

By using genetic engineering, the team isolated a structural gene from the PRRSV Taiwan Strain MD-001 which can activate the animals’ immune response, transplanted it into a banana plant’s chromosomes and used the plant as a bioreactor to develop the subunit vaccine — the vegetant oral immunogenicity.

“After feeding the pigs with 50g of banana leaves from the transgenic banana plants, three times at a two-week interval, the serum and tissue viral loads dropped,” Huang said

He added that the pigs’ immune responses could reach stable levels about four weeks after feeding them with the oral vaccine.

The cost of producing the plant oral vaccine is lower, he said, adding that the vaccine can be mass produced and is easier to preserve and use.

“Unlike the current method using injections, oral vaccines are painless and prevent possible blood contamination,” he said.

Considering the size of China’s hog-breeding industry — estimated at about 500 million — the vaccine could create as much as NT$5 billion to NT$10 billion (US$167 million to US$334 million) in value if it gains a market share of about 10 percent, the team said.

The team’s research result was published in the Plant Biotechnology Journal.