Cryostat sections with tissue amastigotes of Trypanosoma cruzi as a substrate for Chagas' disease serology

Abstract

Sera from 30 chronic chagasic patients together with 52 control samples (34 with other pathological conditions and 18 from normal individuals) were titrated by the indirect immunofluorescent technique (IFA) on Trypanosoma cruzi amastigotes. Acetone-fixed cryostat sections of skeletal muscle of Rockland mice 10 days post-infection with the RA isolate of T. cruzi were used as substrate. Results were compared with titres obtained by conventional IFA on epimastigotes. All 52 control sera had amastigote titres less than or equal to 2 double dilutions (dd) as compared with epimastigote values. Out of the 30 chagasic samples, differences were greater than or equal to 4 dd (less than or equal to 1 log) for 22, 3 dd for 5 and less than or equal to 2 dd for the remaining 3, when comparing amastigote and epimastigote titres. These results show that the use of amastigotes in cryostat sections of infected tissue for performing Chagas' serology in a simple, adequate and sensitive method.

High resolution of Trypanosoma cruzi amastigote antigen in serodiagnosis of different clinical forms of Chagas' disease

“…Our GMT data for IgG antibodies are also close to those obtained with amastigotes from an in vivo system consisting of skeletal muscle sections from T. cruzi-infected mice, which were 3 to 4 times higher than those of anti-epimastigote antigens (15). However, the data reported by Araujo et al (GMT = 640 [2]), who worked with amastigotes from L929 cells, do not agree with our results.…”

Application of two types of Trypanosoma cruzi amastigotes of different virulence to ELISA for Chagas' disease.

“…Kitagawa et al (1987) introduced the method to apply insoluble antigens to ELISA for quantification of some bacterias. Since some works (Gam and Neva, 1977;Aranjo and Guptill, 1984;Cossio et al, 1985) revealed that the use of amastigote antigens was more sensitive than that of epimastigote antigens, we used insoluble antigens of amastigotes of different clones or strain which were cultured in different ways and compared their efficiency as solid-phase antigens.…”

“…However, the enzyme immunoassay has been getting popular because of its easiness and rapidity (Anthony et al, 1974). Some reports indicated that the use of amastigotes as antigens gave better sensitivity than that of epimastigotes (Gam and Nevo, 1977;Araujo and Guptill, 1984;Cossio et al, 1985) but this advantage was limited to the use of whole bodies of fixed amastigotes, suggesting that some important antigens were insoluble in water. Kitagawa et al (1987) reported the successful use of insoluble antigens in water for enzyme immunoassay.…”