19 August 2004

Discovery of a rapid immune response

A new discovery by a research team at the University of Dundee is giving insights into the immune system and how the body is able to respond quickly and tell the difference between harmless foreign bodies and dangerous invaders.

In a paper published by the highly respected journal Science tomorrow (Friday 20th August), Colin Watts and his team describe how they discovered a rapid phase of the immune response that was not previously known to exist.

Professor Watts, Michelle West, Robert Wallin, Alan Prescott and Steve Matthews discovered that a key cell type in the immune system, the dendritic cell, becomes activated within minutes of sensing the presence of invading microorganisms. The new work shows that dendritic cells rapidly reorganise their internal structure and resources to maximise their ability to trigger an immune response.

Dendritic cells are believed by immunologists to be key elements of the immune system. These cells sense invading microorganisms and alert other cells of the immune system by using special sensors called 'Toll-like receptors'. These receptors control the behaviour of dendritic cells which in turn help the immune system to distinguish between 'foreign but harmless' from 'foreign and potentially dangerous'.

Colin Watts explains: "What amazed us was how quickly dendritic cells can respond to signals from pathogens. Within minutes of sensing the presence of a bacterial cell wall component the cells increased their ability to capture foreign material and make it visible to other immune cells called T cells. It became clear to us that there was reorganisation of a complex piece of machinery called the cytoskeleton which is needed to help cells control their shape and movement. We found that the cell rapidly dismantles some elements of the cytoskeleton and uses the building blocks to boost other activities, particularly capture of foreign material. The whole process only lasts an hour or so which on the 2-day time scale of most previous studies on how these cells respond to pathogens is very short.

I believe we have discovered a new and very early chapter in the life story of these remarkable cells. The findings are important because new knowledge usually offers new therapeutic possibilities. For example, for vaccines to work they need to be taken up and processed by dendritic cells.

Our results could lead us to improving the efficacy of common vaccines."

Professor Watts is Head of the Division of Cell Biology & Immunology in the School of Life Sciences, University of Dundee.

By Jenny Marra, Head of Press 01382 344910, out of hours: 07968298585, j.m.marra@dundee.ac.uk