Recent research into the immune system demonstrates that, armed with the rapidly improving tools of modern biotechnology, scientists are progressing nicely towards a working understanding of crucial systems within the human body. "Working understanding" here means sufficently detailed knowledge of the biochemistry to be able to replicate or steer these processes in cells, and then later - armed with advanced medical nanotechnology - to replace component parts altogether.
Every T cell wears a unique molecule, called a T cell antigen receptor, on its surface that it uses to detect pieces of foreign proteins called antigens. These receptors exist in astonishing, and for all practical purposes, unlimited variety--allowing the body to recognize any pathogen it might encounter.
Just as police need evidence of a crime to begin an investigation, T cells must recognize a specific antigen before they start to fight an infection. Dendritic cells constantly scour the body for antigens and present these to T cells for review in the lymph nodes. It is a demanding job. "Just 10 dendritic cells can show viral antigens to over a million T cells in a day," says Dr. Dustin.
Once a T cell's antigen receptor finds an antigen match, the T cell forms an immunological synapse with a dendritic cell through which it queries the dendritic cell for additional information about the antigen and its source in the body. Is the antigen a danger or simply a harmless food protein? The interrogation may last hours, and if the antigen is deemed a threat the T cell starts multiplying, eventually producing thousands of copies of itself. These T cell clones are capable of killing invaders outright and marshaling other cells to destroy them.
In the new study, Gabriele Campi, a graduate student in Dr. Dustin's laboratory, and Kaspar Mossman, a graduate student of Dr. Groves's, created a synthetic dendritic cell using purified antigen and adhesion molecules (molecules that the cell can grip) in a thin fluid coating on a glass surface. In prior studies the antigen was free to move over the entire glass surface, but in this study they set up miniscule chrome barriers, allowing them to modify the pattern of T-cell antigen receptor clusters in the immunological synapse.
"This is the first time that anyone has been able to physically manipulate the immunological synapse and measure the effect on T cell signaling."
This is an early step in the early groundwork for the development of artifical - and far more effective, long-lasting and efficient - immune system components. In all of science, viewing preceeds understanding, which preceeds manipulation and construction. As the tools of nanoscale engineering and then molecular manufacturing become more capable in decades ahead, tremendous opportunities for healthy life extension through engineering and nanomedicine will be there for the taking.