Development and application of a membrane receptor assay for leukotriene B4.

5(S),12(R)-dihydroxy-6-cis-8,10 trans-14-cis-eicosatetraenoic acid (LTB4) is a potent inflammatory mediator generated by human cells. A receptor assay using membranes from cultured HL-60 cells has been developed to quantitate LTB4 with a range of sensitivity from 10 pg to 5 ng. The initial metabolite of LTB4, 20-OH LTB4, has a cross reactivity of 28% while other lipoxygenase products do not significantly compete. This assay has been used to study ionomyocin-induced formation of LTB4 by human neutrophils. The use of membranes from HL-60 cells for the measurement of LTB4 provides a sensitive and highly selective alternative to radioimmunoassay for the determination of the levels of this important eicosanoid in biological fluids and should be useful in the development of antagonists of the LTB4 receptor.