Peripheral blood gamma delta T cells in human listeriosis.

A phenotypical analysis carried out by direct immunofluorescence and two-colour cytofluorometry showed that the number of lymphocytes bearing the gamma delta T-cell receptor heterodimer was increased in the blood of eight children with Listeria monocytogenes infection, mainly due to an expansion of cells identified by monoclonal antibodies which recognize V delta 2 gene products. These findings are further evidence that gamma delta T cells are in some way involved in the immune response directed against human intracellular pathogens.