A s bstract. Various arachidonic acid (AA) metabolites are known to regulate immune cell function(s) and dictate the progression of both acute and chronic inflammatory reactions. Using a model of Schistosoma mansoni egg-induced hypersensitivity granulomas, we have delineated the in vivo effects of inhibitors of cyclooxygenase (CO) and lipoxygenase (LO) pathways on granuloma development and granuloma macrophage I-region-associated (Ia) antigen expression. In addition, by high performance liquid chromatography (HPLC) we have profiled the metabolism ofAA by macrophages that are isolated from granulomatous foci, and have biochemically characterized the in vitro specificity and activity of selected CO and LO inhibitors. The development of hypersensitivity-type pulmonary granulomas in mice was dramatically suppressed by inhibitors with anti-LO activity (nordihydroguairetic acid (NDGA), nafazatrom, and BW755c) in a dose-dependent manner, while indomethacin, which is primarily CO-selective, had no significant effect. Furthermore, NDGA and nafazatrom profoundly arrested the normal progression of preformed granulomatous lesions. The inhibitors of the LO pathway also suppressed the in vivo kinetics of Ia antigen expression by granuloma macrophages. In contrast, indomethacin augmented Ia-antigen expression. The major AA metabolites that were synthesized by the granuloma macrophages were shown to be leukotriene C4 and mono-hydroxyeicosatetraenoic acids. HPLC analysis of AA metabolites from granuloma macrophages that were treated with the various inhibitors confirmed that indomethacin was most CO-selective and NDGA most LO-selective. Nafazatrom and BW755c inhibited AA metabolism by both pathways. Notably, high concentrations ofthe compounds (5 X l0-5 M) tended to suppress all products. Our results suggest that LO products may be important in the generation and maintenance of immune granulomatous inflammatory responses.

The preparation of a reagent which can be used to attach biotin to proteins via a cleavable connector arm is described. The reagent, 3-(4-(N-biotinoyl-6-aminocaproyloxy)phenyl)propionic acid N-hydroxysuccinimide ester (BPE), can acylate amino groups of proteins and other compounds via reaction of the N-hydroxysuccinimide ester function. Compounds which have been covalently labeled with BPE can be selectively retrieved (at physiological pH values) from complex mixtures by adsorbing the target compounds on immobilized avidin. These compounds can be released from the avidin by cleavage of the phenyl ester linkage of the connector arm under conditions which don't denature proteins. Insulin was labeled with BPE. The binding of the labeled insulin to immobilized avidin, and its subsequent release by treatment at room temperature with 1 M hydroxylamine at pH 7 was demonstrated.The highly specific and very strong binding of biotin to avidin (KD -lo-l5 M; (7)) could provide us with a basis for the design of elegant protocols for the retrieval of compounds from cells and physiological fluids even when the compounds targeted for retrieval are present at very low concentrations.For example, a polypeptide hormone that had been covalently labeled with biotin could be incubated with cells and later retrieved by adsorption on immobilized avidin for studies of hormone catabolism and for isolation of hormonereceptor complexes. Unfortunately, the direct application of this approach is usually precluded by the very low rate constant for the dissociation of biotin from