The secretory Onchocerca volvulus protein OvS1/Ov20 exhibits the capacity to compete with serum albumin for the host's long-chain fatty acids

The mechanism by which filarial parasites derive fatty acids bound to the h ost's carrier protein is poorly understood. The capacity of a secretory pro tein of Onchocerca volvulus (OvS1/Ov20) to compete with serum albumin for a rachidonic and other fatty acids was investigated in this study. Binding af finities of the two proteins for the long-chain fatty acids were determined using displacement assays. The fluorescent probes used included 11-((5-dim ethylaminonaphthalene- -1-sulfonyl)amino) undecanoic acid (DAUDA) and cis-p arinaric acid. OvS1 protein bound arachidonic acid with an affinity five-fo ld greater than the affinity exhibited by serum albumin. Oleic acid was bou nd by the parasite protein with an affinity two-fold greater than the affin ity shown by serum albumin. Furthermore, the affinities exhibited by OvS1 p rotein in binding arachidonic and linoleic acid were about two times higher than the affinity for oleic acid. The results suggest that the OvS1 protei n has the capacity to compete with the main host's fatty acid carrier prote in for the long-chain fatty acids, in particular arachidonic acid, the prec ursor for eicosanoids. (C) 2000 Published by Elsevier Science B.V. All righ ts reserved.