The distinct response of gd T cells to the Nod2 agonist muramyl dipeptide

We have begun to approach gd T cells more as prospective innate cells than as conventional T cells. Recent results indicated that purified gd T cells are primed directly in response to pathogen associated molecular patterns (PAMPs) to better respond to secondary signals and increase expression of chemokine and activation-related genes. In microarray and real time PCR analyses of RNA derived from bovine and human gd T cells, transcripts encoding Nod2 were repeatedly amplified. Nod2 is the intracellular receptor for muramyl dipeptide (MDP), a subunit of PGN, functions in regulating innate activities, and was thought to be expressed primarily in APCs. Given our repeated detection of Nod2 transcripts in gd T cells, the specific direct response of gd T cells to MDP was analyzed by microarray, real time PCR, proteome array and in a functional priming assay. The results indicate a subtle activation in response to MDP akin to priming, and suggest a unique mechanism for differential gene expression.

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Kerns HM, Jutila MA, Hedges JF