Human pulmonary macrophages. Functional comparison of cells obtained from whole lung and by bronchoalveolar lavage.

Previous studies have demonstrated that pulmonary macrophages (PM) recovered from bronchoalveolar lavage (BAL) are relatively poor accessory cells for antigen-induced T-lymphocyte proliferation. These studies have suggested that the immune function of macrophages obtained by BAL is representative of the majority of PM. We compared macrophages obtained by BAL with PM from whole lung minces (MIN) for their ability to stimulate T-lymphocyte proliferation. Both populations of PM had similar expression of HLA-DR antigen and were of comparable maturity as determined by staining for MO2 antigen. Production of interleukin 1 by both groups of PM was similar and was significantly less than that produced by monocytes (p less than 0.05). Both populations of PM functioned poorly as antigen-presenting cells when compared with monocytes (p less than 0.05). However, PM from MIN stimulated a mixed leukocyte reaction significantly more (p less than 0.05) than did PM from BAL. Our data suggest that whereas BAL obtains a population of PM with an immunologic function that is largely similar to PM obtained from whole lung, some differences in function may exist.