Kiwi breakthrough could stop ghastly parasite infection

Hookworm contributes to the cycle of poverty. Photo / Thinkstock

A breakthrough by New Zealand scientists could lead to a vaccine to treat a ghastly disease which mostly affects the poorest billion people in the world.

After a decade of research, Professor Graham Le Gros and his team at the Wellington-based Malaghan Institute of Medical Research have demonstrated a never-before-seen interaction between innate and adaptive immune cells, providing a new research pathway to prevent hookworm.

According to the World Health Organisation, hookworm contributes to the cycle of poverty and ill health for communities of people living on less than $2 a day.

A hookworm infection causes childhood and maternal anaemia, wasting, pain, disability and impaired brain development, but has proved impossible to eradicate as rates of reinfection are high.

The nasty parasites reproduce in the gut and the eggs are passed in stool, and the cycle continues when they re-enter the body as humans walk barefoot in unsanitised areas.
It is not found in New Zealand.

Scientists believe the best way to break this cycle would be to create a vaccine for protective immunity, but before that could happen, the immune mechanism that would best protect against hookworm infection needed to be pin-pointed.

Using a mouse model, Professor Le Gros' team stimulated immunity memory - the way a preventative vaccine teaches the immune system body to respond and fight off a disease it has not yet met - and saw the unexpected behaviour of one particular immune cell.

"We have evolved to develop immunity to many parasites, but not hookworm," he said.

"An unusual feature of their life cycle is that it includes migration of the larvae to the lungs before they develop into adults in the gut."

His team were able to create an immune response in the lungs of mice that made it hard for the parasite to live - and break the worm's lifecycle.

"Our hunt is now on the find the right protein adjuvant to combine with these immune cells - to teach a human body to have a memory of how to fight hookworm."

Further, the team demonstrated one immune cell - the innate lymphoid (IL) cells - trigger immunity and work with other immune cells, the Macrophages and T helper cells.

Previously, IL cells were not thought to be involved in creating a cellular memory to fight off disease.

The research, published in Nature Communications, was assisted by synthetic chemist Dr Gavin Painter from the Ferrier Research Institute at Victoria University of Wellington.