Factors influencing the assessment of anticoccidial activity in cell culture

Abstract

SUMMARYA comparative study has been made of the factors influencing the assessment of anticoccidial potency in vitro against Eimeria tenella using established anticoccidials and arprinocid and some of its analogues. Drugs whose potency depended upon medium composition were amprolium, lasalocid and halofuginone. There was a difference in strain sensitivity with robenidine. Host cell type had an important effect on potency of monensin, decoquinate, arprinocid and its analogues. Arprinocid was active in chick liver cell systems but totally inactive in chick kidney cell systems, although its N-oxide was active in both cell types. Arprinocid-containing medium, conditioned by supporting the growth of chick embryo liver cell cultures, had an anticoccidial effect on E. tenella, growing in chick kidney cells. It is deduced that the anticoccidial activity of arprinocid in the chick is due to a metabolite.

Novel anti-malarial hydroxynaphthoquinones with potent broad spectrum anti-protozoal activity

“…The activity of hydroxynaphthoquinones against E. tenella (Weybridge) grown in embryonic chick liver cells was tested according to the method described by Latter & Wilson (1979). The only modification to the method described was the use of NCTC 135 medium supplemented with 5 % foetal calf serum as tissue culture medium.…”

Further investigation of anticoccidial activity of 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine

“…Concentrations of compound I were measured in ceca and plasma to determine the relationship between concentrations in tissue achieved in vivo and potency in vitro. In birds fed compound I at 15 ppm continuously for 5 days, concentrations of compound I were (10). To investigate whether compound I also requires activation in the liver, we incubated compound I and arprinocid with primary cultures of embryonic chicken liver cells and then screened the conditioned media against E. tenella in vitro in the ELISA-based screen.…”

Anticoccidial effect of halofuginone hydrobromide against Eimeria tenella with associated histology

“…Because of the different environments in which parasite cells live, and due to differing cell strains, mediums, parasite strains, together with many factors that influence anticoccidial activity, (such as absorption, distribution, metabolism and pharmacokinetics), results observed in vitro have not always represented the true activities in vivo (Latter and Wilson 1979;McDougald and Galloway 1973). At present, no success has been achieved in fully elucidating the mode of action of halofuginone at a molecular level and little is known about how halofuginone reaches parasitized cells (whether by native/passive absorption or by simple downward movement into the cecum), or other aspects of its distribution, metabolism and pharmacokinetics in chickens.…”