Investigations into the mechanism of vaccine- induced protection against the gastric pathogen Helicobacter pylori. [ 2005 - 2007 ]

Research Grant

Researchers: Dr Anna Walduck (Principal investigator)

Brief description Helicobacter pylori (H. pylori) is the most common gastro-intestinal pathogen worldwide and infects up to 20 % of the Australian population. Infection is thought to be acquired in childhood, and may cause acute or chronic gastritis, and gastric ulcer later in life. H. pylori infection is also strongly associated with the development of gastric cancer, the second most common cause of cancer death world- wide. In the long term a vaccine will be the best and most cost effective way to control this disease. Vaccination against H. pylori is effective in laboratory animal models. A few vaccines have entered the early phases of clinical trials in human volunteers, however the results have been disappointing. We still do not understand how vaccination leads to killing of bacteria in the stomach, although it is known that antibodies are not responsible. A better understanding of how vaccination works in mice will help the design of vaccines for humans. In a novel approach to study vaccination, the gene expression pattern in the stomachs of immunized mice was analyzed using DNA micro-array technology. In this way we identified several novel genes, and as a result we have developed a new theory for how vaccination might lead to killing H. pylori. We propose that a combination of factors, act together to control H. pylori in the stomach: Leptin, known chiefly as the Obese gene, is a hormone produced by fat cells and controls appetite. Recently leptin has also been shown to influence immune cells (T- cells) in the stomach mucosa. These T-cells in turn send signals to the (epithelial) cells on the surface of the stomach which induces them to produce other proteins; some of which we believe may slow the fast-swimming H. pylori bacteria, and some small anti-microbial proteins (defensins), which are able to kill the bacteria directly by making holes in their membranes. The results of this research will be used to help design better H. pylori vaccines for humans.

Funding Amount $AUD 276,000.00

Funding Scheme NHMRC Project Grants

Notes New Investigator Grant