Alveolar macrophages, blood monocytes, and density-fractionated alveolar macrophages differ in their ability to promote lymphocyte proliferation to mitogen and antigen.
We compared the relative abilities of alveolar macrophages (AM), blood monocytes (BM), and density-fractionated AM to support antigen- and mitogen-induced proliferation of autologous T cells in normal volunteers. The AM were able to promote the T-cell proliferative response to antigen, but they did so less effectively than did the BM. Density-fractionated AM were heterogeneous in their ability to support T-cell responses. More proliferation occurred with the densest AM than with the least dense AM. In contrast to antigen-induced responses, mitogen-induced responses were supported more effectively by AM and density-fractionated AM than by BM. The ability of AM, density-fractionated AM, and BM to support T-cell responses did not correlate with surface expression of class II major histocompatibility determinants. Addition of purified IL-1 resulted in a partial restoration of T-cell proliferation when low-density AM were used but no augmentation when unfractionated AM were used. This suggests that reduced IL-1 activity may partially explain the decreased ability of low density AM to promote T-cell responses, but that other processes may also contribute to differences in accessory cell function among AM, BM, and density-fractionated AM.
D000941:Antigens / Q000276:immunology; D001773:Blood Cells / Q000502:physiology*; D001980:Bronchi / Q000166:cytology; D002499:Centrifugation, Density Gradient; D006683:HLA-DQ Antigens / Q000276:immunology; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008264:Macrophages / Q000276:immunology / Q000502:physiology*; D008934:Mitogens; D009000:Monocytes / Q000502:physiology*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000276:immunology / Q000502:physiology*; D007507:Therapeutic Irrigation
D000941:Antigens; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D007375:Interleukin-1; D008934:Mitogens