Distribution and leukocyte contacts of gammadelta T cells in the lung.

Pulmonary gammadelta 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 gammadelta and alphabeta T cells are distributed differently in the normal mouse lung. The gammadelta T cells have a bias for nonalveolar locations, with the exception of the airway mucosa. Subsets of gammadelta T cells exhibit further variation in their tissue localization. gammadelta and alphabeta T cells frequently contact other leukocytes, but they favor different cell-types. The gammadelta 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 gammadelta T cells with these sentinels likely is related to their protective role.