Anti-Trypanosoma cruzi and anti-laminin antibodies in chagasic patients after specific treatment

Abstract

The antibody response to Trypanosoma cruzi epimastigote and trypomastigote stages, as well as to laminin, was studied in several groups of chagasic patients. In six patients who were cured of the parasite, the serum antibody titers as revealed by indirect immunofluorescence and hemagglutination tests against epimastigotes (conventional serology) and a complement-mediated lysis test with living trypomastigotes did not differ from those of normal individuals. In seven presumably cured patients, although the complement-mediated lysis test turned negative, conventional serology remained positive. Sera from this group of so-called "dissociated" patients presented significant lower mean antibody titers against epimastigote but not trypomastigote stages than did sera from 14 untreated patients (P < 0.01). Most of the antibodies against trypomastigotes, including the residual levels found in cured patients, were absorbed by mouse laminin. In fact, significantly higher titers of anti-laminin antibodies were observed in sera from untreated chagasic patients (1.131 + 0.458) and cured patients (1.103 ± 0.572) than in sera from eight normal individuals (0.459 ± 0.402) (P < 0.01). The anti-laminin titers were higher in sera of patients of blood group A or O than in those of patients of group B or AB. In Western blotting (immunoblotting) analysis against trypomastigotes, sera from chronic untreated patients recognized many polypeptide bands ranging from 26 to 160 kilodaltons, whereas no protein bands were observed with sera from cured patients. Only faint bands of parasite proteins were observed with sera of dissociated patients. In conjunction, the above data suggest that the anti-trypomastigote antibodies which persist after parasitological cure of patients with Chagas' disease are due mainly to cross-reactive epitopes from mouse lamimn.

Glycoconjugates of Trypanosoma cruzi: A 74 kD antigen of trypomastigotes specifically reacts with lytic anti‐α‐galactosyl antibodies from patients with chronic Chagas disease

“…The compartment below the cut-off line of the Ch serum reactivities with the F2 fraction gathered the antibody responses of NHS and sera from cured patients and dissociated sera. The titers of the last two groups were higher than those for NHS and probably represent the cross-reactivity with F2 of low affinity anti-Gal antibody clones, which bind to mouse laminin (25) and are expanded nonspecifically in Chagasic patients.…”

“…We have shown that anti-Gal from Chagasic patients have a much greater affinity for trypomastigote surface antigens than natural anti-Gal froin healthy individuals, using different immunological reactions (17). On the other hand, natural and parasite-induced anti-Gal bind equally well to non-parasitic molecules carrying the D-Gala-(1-+3)-D-Gal epitope such as mouse laminin (25,26).…”

Flow cytometry, a new approach to detect anti-live trypomastigote antibodies and monitor the efficacy of specific treatment in human Chagas' disease

“…The reason for the continuing presence of CSA in the serum of cured patients is still an open question. However, a number of hypotheses have been put forward to explain this, such as the presence of residual parasite antigens following treatment (3), the influence of parasite mimic epitopes expressed by anti-idiotypic antibodies (9), and the cross-reactivity of anti-galactosyl ␣(1-3) galactose antibodies with T. cruzi epitopes (8).…”

Antibody drop in newborns congenitally infected byTrypanosoma cruzitreated with benznidazole

“…Cure is proved by an immunological test 1 year after treatment because of the persistence of anti‐ T. cruzi antibodies (Andrade et al. 1988; Gazzinelli et al. 1988, 1993; Freilij & Altcheh 1995).…”