Vaccine breakthrough from Otago research

Researchers with strong University of Otago links have made "very exciting" progress in their efforts to develop the first effective oral vaccine to protect against tuberculosis (Tb).

Tb kills more people worldwide than any other bacterial disease- 1.4 million in 2010, mostly in developing countries including Africa, Southeast Asia and the Western Pacific.

In New Zealand, there are about 600 notifications of the disease each year and 300 new cases diagnosed.

A new study led by Dr Jo Kirman, of the Otago microbiology and immunology department, found that in mice, an innovative oral vaccination formula can induce stronger and longer-lasting immune response than the current needle vaccination against Tb.

Dr Kirman says the oral vaccine, potentially delivered as a syrup or pill, would be easier to administer and - importantly in developing countries - would not require a health professional to deliver.

Otago microbiology PhD student Lindsay Ancelet, who was the first author of the study, said that giving the vaccine by mouth to newborn babies also reduced possible risk of other infection through needle use, in developing countries.

An oral vaccine was more effective than needle-based approaches because it directly targeted the mucosal immune system - a network including the gut and lungs - instead of achieving the systemic response triggered by injected vaccines, researchers said.

For an oral vaccine to work, the bacteria need to be alive, but could be destroyed by the harsh environment of the stomach.

This problem had been overcome with the development by Dr Frank Aldwell and colleagues from Otago University-based Immune Solutions Ltd of a lipid formulation called LiporaleTM, researchers said.

This formula coats the BCG bacteria, allowing them to survive.

Dr Kirman and colleagues Dr Aldwell, Fenella Rich, of the Malaghan Institute, and Ms Ancelet compared the immune response in the spleen and lungs of mice vaccinated with the new formulation, LiporaleTM-BCG, to the response from injected vaccinations.

The new oral vaccination induced a long-lived immune response, evident by the detection of increased numbers of tuberculosis-specific T cells in the lungs and spleen up to 30 weeks after vaccination, Dr Kirman said.

These "promising" findings were published yesterday in the international journal "PLOS ONE".

The researchers are hoping the vaccine will attract more Health Research Council funding in order to further understand the immune response and to undertake the necessary safety tests.

If funding could be gained and good progress continued, clinical trials involving humans could take place within five years, they said.

- john.gibb@odt.co.nz