Isolation, expansion and characterisation of alloreactive human Th17 and Th1 cells.

Interleukin 17 producing T helper cells (Th17) and IFNγ producing Th1 cells are distinct subsets of effector memory CD4(+) T cells that are crucial to host immunity and have been linked to the pathology of certain inflammatory autoimmune diseases. We have developed a method for the isolation and long term culture of human Th17 and Th1 cells. Using allogeneic stimulation we have cultured homogeneous populations of Th17 and Th1 cells to large cell numbers. These alloreactive cell lines were established from CD4(+)CD45RO(+) memory T cells expressing, or lacking, CCR6 and CCR4. The Th17 cells were derived only from cells expressing both CCR6 and CCR4 whereas the Th1 cells, secreting IFNγ, were derived from cells lacking CCR6 and CCR4. The CCR6(+) and CCR4(+) memory T cells also gave rise to a third population of polyfunctional cells expressing both IL-17 and IFNγ. All cell populations expressed the TCR αβ and the Th17 cells characteristically expressed CCR6, CCR4 and CD161. The use of this protocol will ultimately allow for the comparative analysis of the Th17 and Th1 cells.