Measurement of parasite-specific antibody responses using a tritiated avidin-solid phase radioimmunoassay

A solid phase radioimmunoassay (RIA) to measure parasite-specific antibody responses has been developed. The assay utilizes 3H-labeled avidin as the indicator molecule and represents a marked improvement in detection of specific antibodies to Trypanosoma cruzi over previously used RIA. Avidin is easily labeled to high efficiency (3.6 X 10(5) cpm/micrograms) under very mild conditions using N-succinimidyl-[2,3-3H]propionate, and the high efficiency of avidin-biotin binding coupled with the increased safety and longer half-life of the labeled reagent give this method advantage over currently used 125I-labeled Ab RIAs.