Antigenic specificity and subset analysis of T cells isolated from the bronchoalveolar lavage and pleural effusion of patients with lung disease

SUMMARY Cellular infiltraicsofbronchoalvcolarlavage(BAL)andpleuralcffusion from patients with tuberculosis (TB) and lung cancer were characterized for the presence of different T cell subsets by phenotypic analysis. The specificity of ihe T cells for mycobacierial antigens was then compared for the two disease compartments. The composition ofT cell subsets within the BAL. in contrast to pleural effusion cells (PEC), revealedevidenceofsequestrationofCD8’ cells. BALTcellswerefoundtobeapredominantly CD29’ DR’ memory population ofactivatcd cells. Although polyclonal populations of BAL T cells proliferated poorly to Mycohacterium tuberculosis antigens, mycobacierial antigen‐reactive monoclonal T cell populations could be derived from the alveolar compartment. Two clones were shown to recognize the 65‐kD heat shock protein of mycobactcria. and one of these clones recognized a conserved sequence of the molecule. Several BAL‐derivcd clones, responding to a mycobacterial soluble extract, did not. however, recognize purified mycobacterial antigens, previously identified as highly stimulatory for PEC‐derivcd T cells. T cell clones, derived from PEC of two TB patients, responded to the 38‐kD and 71‐kD. as well as the 65‐kD mycobacterial antigens. Examination of the activation requirements of BAL‐derivcd T cell clones, specific for mycobacterial antigens, revealed that exogenous IL‐2 was necessary for the T cells to sustain proliferation. This was in contrast to the mycobacterial antigen‐reactive T cells cloned from PEC. These results suggest that T cell populations with distinct antigen specificities and activation requirements arc present in BAL and PEC.