Radiorespirometric detection of macrofilaricidal activityin vitro

Abstract

SUMMARYAnin vitromethod for studying radiorespiration has been adapted to single macrofilariae. Using this method viable (but not heat-killed)Dipetalonema viteaeandOnchocera gibsonimacrofilariae evolved measurable amounts of14CO2from L-[U-14C]glutamine. Nonlinear and less uniform rates of14CO2evolution were demonstrated with D-[U-14C]glucose, [1-14C]acetate and [1-14C]octanoate. These findings led us to develop anin vitroscreen in which inhibition of14CO2evolution from L-[U-14C]glutamine was used as a parameter for gauging macrofilaricidal activity. Using this screen we have examined the activity of 17 ‘so-called’ antifilarial standards and found a greater degree of sensitivity than shown by other biochemical criteria. Other data obtained suggest a role for radiorespirometry in determining the viability of fragments ofOnchocerca tissue.