( Using a new form of microscopy to penet...)Scientists directly view immune cells interacting to avert autoimmunity

The technique, known as two-photon laser-scanning microscopy, was able to focus deep within the lymph node of a diabetic mouse, allowing the researchers to show that immune cells known as T regulatory, or Treg, cells control the destructive action of rogue autoimmune cells when each of the two cell types interact with a third kind of cell.

The role of the third cell type -- the antigen-presenting dendritic cell -- in preventing autoimmune attacks of healthy tissue has been a focus of intense research over the last 15 years. The new study supports one contending hypothesis: It is not the interaction between the two types of T cells, but rather the interaction of each with the dendritic cells that leads to protection from autoimmune assaults.

Analyzing these physical interactions experimentally in living organs or even in cell cultures has been impossible before now, the scientists note. Their long-term aim is to use such imaging to diagnose immune diseases such as type 1 diabetes, and to further develop therapies that act at the level of T cell interactions.

The research, published online this week in Nature Immunology, includes online videos of these immune cell interactions ?the first time this has been accomplished.

The scientists used fluorescent dye to mark different types of cells so they could directly observe the interactions of the key cell types involved in initiating autoimmune attacks and the control of their actions by therapeutic regulatory T cells.

The "nonobese diabetic" (nob) mouse model used in the research is considered the "prototypic" model for human type 1 diabetes, said Qizhi Tang, PhD, UCSF adjunct assistant professor in the UCSF Diabetes Center and lead author of the paper. The researchers expect the findings from t
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Source:University of California - San Francisco