UBC LogoThis is an interesting piece of news. A team of University of British Columbia microbiologists seems to have recognized a chief defence mechanism used by the immune system against Listeria. This could possibly result in strong implications for the potential growth of vaccines.

Listeria is known to be the bacteria which cause listeriosis, a food-borne infection. It was estimated to have caused approximately 22 deaths in Canada in an August 2008 outbreak in meat products produced by Maple Leaf Foods.

“We know a great deal about how our body’s adaptive immune system reacts to viruses but generally very little about immune response against bacterial infections,” says Wilfred Jefferies, a professor at UBC’s Michael Smith Laboratories and Biomedical Research Centre.

This study seems to have focused on dendritic cells which assist in activating the immune system. Supposedly, dendritic cells collect pathogen materials and provide them to other parts of the immune system such as T-cells. This mechanism is believed to have been called as cross-presentation.

“Dendritic cells are gatekeepers; they are small in numbers but very active in patrolling tissues that are in contact with the external environment, such as the skin,” continues Jefferies, who is also a member of the UBC Blood Research Centre, the Brain Research Centre and the Vancouver Coastal Health Research Institute.

Jefferies further elucidated that, “Their job is to apprehend the pathogens while avoiding getting infected. We’ve found that they achieve this by sampling bits and pieces of the bacterial pathogens in the area surrounding infected cells, instead of directly approaching the bacteria.”

The findings of the study revealed that when cross-presentation is deactivated, the host seems to become strictly compromised in its ability to produce suitable T-cells that would probably help it fight the Listeria infection.

Dr. Bhagirath Singh, Scientific Director at CIHR’s Institute of Infection and Immunity stated that, “Better understanding of the body’s immune system is the key to develop new strategies for treating bacterial infections and for creating new vaccines for Listeria. Dr. Jefferies’s work advances our collective effort to prevent listerosis by focusing on the way our immune defences are wired and triggered upon initial infection by invading pathogens.”

Jefferies claimed that this study may perhaps establish an essential role of dendritic cell cross-presentation in fighting bacteria infections. Moreover, it seems to lay emphasis on how we can influence and engage immune responses. He anticipates that this information may eventually help in designing of vaccines against bacteria and other pathogens.

The findings of the study have been published in the online journal, PLoS ONE.