Leukotriene B4, but not (12S)-leukotriene B4, coupled to fluorescein-labeled human serum albumin interacts specifically with human T lymphocytes, as assessed by fluorescence-activated flow cytometry. Approximately 11% of blood T lymphocytes bind the fluorescent conjugate of leukotriene B4. The leukotriene B4-reactive T lymphocytes are distributed between the suppressor-cytotoxic (14%) and helper-inducer (8%) subsets, which were identified concurrently by phycoerythrin-labeled monoclonal antibodies to subset-specific antigens. Leukotriene B4, but not (12S)-leukotriene B4 or leukotriene C4, enhances significantly the proliferation of mitogen-stimulated purified suppressor-cytotoxic T lymphocytes, at concentrations of 10(-12) M to 10(-6) M, and inhibits significantly the proliferation of mitogen-stimulated purified helper-inducer T lymphocytes, at concentrations of 10(-8) M to 10(-6) M, as assessed by the uptake of [3H]thymidine. The net effect of leukotriene B4 on blood T lymphocytes is immunosuppression, which may be expressed in some human hypersensitivity and inflammatory diseases.

• 1 PO1 AI 19784/AI/NIAID NIH HHS/United States
• 1 RO1 HL 31809/HL/NHLBI NIH HHS/United States