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Successful animal in utero vaccination method may impact human medicine

Animal research scientists may shed some new light on the transmission of infectious diseases from mother to fetus in the womb and during birth. Veterinary Infectious Disease Organization (VIDO), a leading vaccine research institute based in Saskatoon, Sask., has demonstrated strong immune responses can be induced in lambs immunized in the womb.

“This has huge implications for human health,” says Dr. Philip Griebel, VIDO Immunology Program Director. “A woman with HIV has a 99 percent chance of transmitting it to her child at the time of birth or through breast feeding.

“Essentially, we may have found a way to induce active immunity in the fetus to give the child a fighting chance after birth. Besides HIV, other agents can be transmitted at birth, including chlamydia, streptococcus and Herpes Simplex Virus, and those are often fatal to newborn children.”

VIDO develops vaccines to fight disease barriers in food animal production and to combat food safety issues. Basic research in those areas often has application in human health research. “Because of new technologies, such as genomics, and the inherent similarities in how animals and humans fight disease, there is a convergence of human and animal health research.”

The in utero vaccination technique was discovered while Griebel’s team was searching for DNA vaccine delivery methods that captialize on the powerful mucosal disease-fighting response. Oral delivery methods didn’t work, which prompted in utero vaccination, he says. “We injected the vaccine through the uterus wall and into the lamb’s mouth.”

Every one of the lambs responded strongly with just one vaccination. In previous work where older sheep were orally injected with vaccines, little or no response was detected. Often, DNA vaccines need to be administered two or more times to induce a strong response.

“It was amazing that a single vaccination stimulated such a strong response in the lambs,” Griebel says, “especially considering the DNA was given with distilled water and without any agents to enhance uptake.”

Griebel has now taken the next step. He vaccinated lambs in utero against Bovine Herpes Virus and then exposed the newborn lamb to the virus. “The lambs immunized in utero were able to eliminate over 99 percent of the virus when they were challenged. So they actually had an effective, protective immune response.”

The research has drawn tremendous interest from the research community. The leading scientific journal, Nature Medicine, published an article on the in utero research last year.

In utero vaccination has little application in commercial food animal production, because it’s time consuming and not cost-effective, says Griebel.

In humans, in utero vaccination methods can be administered with available technology. “Doctors are doing amniocentesis to check for genetic defects during pregnancy using an ultrasound-guided needle to collect samples of fluid around the fetus or to get some fetal cells. With this same technology, they could deliver the vaccine into the mouth of the fetus,” Griebel says.

Currently, Griebel is further testing in utero vaccination for Hepatitis B, a pathogen directly related to human health. “Hepatitis B is a big issue in human infants and our research is indicating in utero vaccination may be an excellent way to fight the disease.”

More projects could be carried out, depending on the funding, he says. “We have proven that this method works and the implications for human health are profound.”

VIDO is a non-profit institute, wholly owned by the University of Saskatchewan and is a global leader in food animal and poultry vaccine research for the control of infectious diseases. It operates with substantial support from the Province of Saskatchewan and the Province of Alberta. This project is funded by Canadian Institutes of Health Research (CIHR), Alberta Agricultural Research Institute (AARI), Deutsche Forschungsgemeinschaft (DFG) and core funding from Agricultural Development Fund (ADF).

VIDO information at www.vido.org

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