Distribution and leukocyte contacts of    T cells in the lung

Pulmonary gamma delta T cells protect the lung and its functions, but little is known about their distribution in this organ and their relationship to other pulmonary cells. We now show that gamma delta and up T cells are distributed differently in the normal mouse lung. The gamma delta T cells have a bias for nonalveolar locations, with the exception of the airway mucosa. Subsets of gamma delta T cells exhibit further variation in their tissue localization. gamma delta and up T cells frequently contact other leukocytes, but they favor different cell-types. The gamma delta T cells show an intrinsic preference for F4/80(+) and major histocompatibility complex class II+ leukocytes. Leukocytes expressing these markers include macrophages and dendritic cells, known to function as sentinels of airways and lung tissues. The continuous interaction of gamma delta T cells with these sentinels likely is related to their protective role.