Evaluation of drug activity against intracellular forms of Trypanosoma cruzi employing enzyme immunoassay.
OBJECTIVE
To describe application of a new method for the evaluation of anti-Trypanosoma cruzi activity against intracellular forms.


METHODS
Vero fibroblasts in 96-well tissue culture plates were infected with trypomastigote forms of T. cruzi. Amastigotes growth was estimated after 24 and 96 h both by microscopic counts of Giemsa-stained monolayers and enzyme-linked immunoIsorbent assay (ELISA). ELISA was performed directly on the fixed cultures using a rabbit anti-T. cruzi immunoIglobulin as the first antibody and a peroxidase-labelled antirabbit immunoglobulin as the second antibody. Three chemical series of structural analogous of gentian violet, thiadiazines and derivatives of 5-nitrothiophene-2-carbaldehyde as well as three reference compounds (nifurtimox, benznidazole and gentian violet) were then assayed. The anti-T. cruzi activity of all of them had been determined previously by microscopic counting of Giemsa-stained infected cultures.


RESULTS
None of the assayed compounds showed better activity than the reference ones, but the application of the enzyme immunoassay to quantify the inhibition of growth amastigotes is of great interest, as it yielded results comparable with microscopic counts.


CONCLUSIONS
ELISA can be applied to pharmacological screening, with some advantages over the microscopic examination, including possible automation, rapidity and objectivity in assessment.
Martínez Díaz
R A
RA
Departamento de Medicina Preventiva (Parasitología), Facultad de Medicina, Universidad Autónoma de Madrid, Spain. rafael.martinez@uam.es
Escario
J A
JA
Nogal Ruiz
J J
JJ
Gómez Barrio
A
A
D000818:Animals; D014355:Chagas Disease / Q000188:drug therapy*; D046508:Culture Techniques; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D007136:Immunoglobulins; D011817:Rabbits; D014344:Trypanocidal Agents / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000187:drug effects*
D007136:Immunoglobulins; D014344:Trypanocidal Agents