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CHARACTERIZATION OF NORMAL HUMAN LUNG LYMPHOCYTES AND INTERLEUKIN-2-INDUCED LUNG T CELL LINES
Citation:
Becker, S., D. Harris, AND H. Koren. CHARACTERIZATION OF NORMAL HUMAN LUNG LYMPHOCYTES AND INTERLEUKIN-2-INDUCED LUNG T CELL LINES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-90/527 (NTIS PB91213504).
Description:
Lymphocytes from the lower respiratory tract were obtained by bronchoalveolar lavage of healthy, non-smoking individuals. arious monoclonal antibodies characterizing activated T cells, helper-inducer and suppressor-inducer T cell subsets, and naive versus memory cells were used to define the phenotype of these lymphocytes. he highly variable CD4/CD8 ratio (0.3 to 6.6; mean =2.1) and the large proportion of the T cells expressing HLA-DR (9 to 38%; mean=2.1%) suggested that the T cells were recently activated by antigens selectively stimulating either helper, or cytotoxic/suppressor T cell function. ndeed the CD45RA antigen, a marker characteristic of suppressor-inducer T cells when coexpressed with CD4, and naive T cells in general, was absent from T cells in most preparations (0 to 17%; mean=5%), while of all lung T cells. he majority (<70%) of the CD4+ helper T cells was CD45RO+ CD45RA-, a phenotype found on T cells that provide help for B cell immunoglobulin synthesis. ung T cells proliferated poorly in response to phytohemagglutinin and concanavalin A but did respond to activation with low concentrations of anti-CD3 mAB (2 to 25 ng/ml) and to interleukin-2 (IL-2) alone to similar extent as did autologous peripheral blood lymphocytes. timulation of lung cells having a CD4/CD8 ratio of <2 with IL-2 (100U/ml) resulted in outgrowth of helper T cell lines (CD2, CD3, CD4, TCRa/B, CD45RO) with no cytotoxic activity against K562 tumor target cells. n contrast, stimulation of cell preparations with a 4/CD8 ratio of <2 resulted in T cell lines with low cytotoxic activity against K562 cells. hese latter lines contained >40% CD8+ cells, all of which expressed the TCRa/B. ytotoxic activity did not correlate with expression of natural killer (NK) antigen CD56 (Leul9). elper cell lines were maintained for at least 3 mo in culture, while cytotoxic cell lines proliferated for <6 wk. hese data show that the lower respiratory tract of humans contains immunocompetent lymphocytes that may have been recently activated and are long-lived memory cells of either the helper or the cytotoxic/suppressor cell type, both of which are capable of proliferation in response to appropriate simulation (anti-CD3 mAB or IL-2).