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

Cellular infiltrates of bronchoalveolar lavage (BAL) and pleural effusion from patients with tuberculosis (TB) and lung cancer were characterized for the presence of different T cell subsets by phenotypic analysis. The specificity of the T cells for mycobacterial antigens was then compared for the two disease compartments. The composition of T cell subsets within the BAL, in contrast to pleural effusion cells (PEC), revealed evidence of sequestration of CD8+ cells. BAL T cells were found to be a predominantly CD29+ DR+ memory population of activated cells. Although polyclonal populations of BAL T cells proliferated poorly to Mycobacterium tuberculosis antigens, mycobacterial 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 mycobacteria, and one of these clones recognized a conserved sequence of the molecule. Several BAL-derived clones, responding to a mycobacterial soluble extract, did not, however, recognize purified mycobacterial antigens, previously identified as highly stimulatory for PEC-derived 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-derived 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 are present in BAL and PEC.