Figure 4.

5-LOX protein expression and metabolite production. (a) Western blot of 5-LOX in MOLT4 and Jurkat T-cell lines and peripheral blood T lymphocytes. Cells were lysed and the cytosolic fraction was retrieved by ultracentrifugation. Equal amounts of protein (25 μg) were subjected to SDS–PAGE on 4–15% gradient gels, then transferred and immunoblotted using anti-5-LOX monoclonal antibody. Lane 1, molecular weight standard; lane 2, Jurkat cells; lane 3, MOLT4 cells; lane 4, peripheral blood T cells; lane 5, neutrophils. (b) Synthesis of LTB₄ and LTC₄ by Jurkat cells. Cells were activated by CD2–CD3–CD28 crosslinking. Supernatants were harvested at different times and production of LTB₄ and LTC₄ was quantified by EIA.