S. M. Gonzalez Cappa

Bio: S. M. Gonzalez Cappa is an academic researcher from University of Buenos Aires. The author has contributed to research in topics: Trypanosoma cruzi & Antigen. The author has an hindex of 15, co-authored 28 publications receiving 635 citations. Previous affiliations of S. M. Gonzalez Cappa include National Scientific and Technical Research Council.

Mice infected with Trypanosoma cruzi produce antibodies against the enzymatic domain of trans-sialidase that inhibit its activity.

Abstract: trans-Sialidase (TS) is an enzymatic activity described only for trypanosomes that is involved in the invasion of host cells by Trypanosoma cruzi. The enzyme that is shed by the parasite is made of two domains, the C-terminal region containing immunodominant amino acid repeats that define the SAPA antigen and the N-terminal domain that contains the putative region for enzymatic activity. The SAPA antigen induces a strong humoral response detected shortly after infection, both in humans and in mice. This response is directed to the immunodominant domain but is irrelevant in terms of neutralization of TS activity. We now show that TS activity can be detected in sera from acutely infected mice. However, mice infected with a T. cruzi strain whose growth can be controlled by the host did not have detectable levels of TS activity in sera. In fact, sera from these mice were able to abolish TS activity. This inhibition was due to the presence of specific antibodies directed against the enzymatic domain of the protein since they also abolish the activity of a recombinant molecule lacking the immunodominant amino acid repeats. The neutralizing antibodies were present from day 30 after the infection, while antibodies to the immunodominant repeats were detected by day 8 postinoculation, suggesting that the in vivo role of these repeats is to defect the humoral response to the repeat domain until the infection is established.

Antibodies Inhibiting Trypanosoma cruzi Trans-Sialidase Activity In Sera From Human Infections

Abstract: Trans-sialidase, an enzyme that transfers sialic acid among macromolecules, has been implicated in invasion of host cells by Trypanosoma cruzi, the agent of Chagas' disease. Most antibodies produced in natural and experimental infections are directed to the highly antigenic C-terminal domain (shed acute-phase antigen). These antibodies do not inhibit the trans-sialidase activity, which is present in the N-terminal domain of the molecule. Antibodies able to inhibit trans-sialidase in sera from human infections have been found. TIA (trans-sialidase inhibition assay) was positive in sera from patients with acute and chronic infections. Healthy and congenitally infected infants born to mothers with Chagas' disease were also TIA-positive, but the antibody titers diminished within months after birth or after treatment. Thus, antibodies neutralizing trans-sialidase are detectable in most forms of T. cruzi human infections, and TIA may be useful in the diagnosis of Chagas' disease.

The effect of immuno-depression due to neonatal thymectomy on infections with trypanosoma cruzi in mice

Abstract: Neonatally thymectomized C3H or Rockland mice infected with trypanomastigotes of Trypanosoma cruzi had higher parasitaemia and shorter survival than their non-thymectomized counterparts. The appearance of antibodies detectable by IFT, IHA or DAT was delayed in neonatally thymectomized mice infected with epimastigotes of T. cruzi. Less thymectomized than non-thymectomized mice survived infection with epimastigotes. Our findings suggest that thymus-dependent, immune mechanisms are involved in controlling infection with T. cruzi in mice.

Trypanosoma Cruzi ノ培養及其ノ培養基

Abstract: • Protozoan, 16-20 mm (trypomastigotes) 1.5 ¥ 4.0 mm (amastigotes) • Order: Kinetoplastida • Family: Trypanosomatidae • Metacyclic trypomastigotes and amastigote life-cycle stages found in human hosts. Metacyclic trypomastigotes (hemoflagellates) are intermittently found in the peripheral blood and are the stage that transmits the infection to vectors or blood recipients. Amastigotes are intracellular, tissue-dwelling forms, often associated with cardiac tissue.

Chagasic Cardiopathy Demonstration of a Serum Gamma Globulin Factor Which Reacts with Endocardium and Vascular Structures

Abstract: Twenty-four out of 25 patients with Chagas' heart disease have circulating immunoglobulins which react by indirect immunofluorescence technique with endocardium, interstitium and blood vessels of the heart. With skeletal muscle the reaction was observed in interstitium and vascular structures, but with other organs it was limited to vascular structures. This endocardial-vascular-interstitial factor (EVI) fixed complement. Some evidence indicated that this reaction could be obtained using the serum and tissues from the same patient: for instance, in one positive case a right atrium biopsy was performed. When this substrate was used for indirect immunofluorescence, employing the patient's own serum, positive results were obtained. Specificity is not related to AB blood group systems, or to Forssman or Wassermann antigens. The reacting factor was effectively absorbed from sera with organ homogenates, and with guinea pig red blood cells although it was independent of heterophil antibodies. In almost all cases studied, the EVI factor of the serum, when absorbed with epimastigotes of T. cruzi, results in a negative reaction, suggesting that the genesis of the reacting gamma globulin is related to antigens of T. cruzi.The EVI factor was also observed in 19 of 47 asymptomatic controls from an endemic area with positive serology for T. cruzi and in 3 of 27 with negative serology. These 3 cases had anti-T. cruzi antibodies in titers just below those considered of clinical value. The EVI factor was not observed in 119 normal individuals and 286 patients with selected cardiovascular diseases or another pathology from a nonendemic area. These findings and those mentioned above were statistically significant (P < 0.001). These results indicate the possibility of a more accurate diagnosis of chagasic myocardiopathy based on the study of the EVI factor, because in an individual case the diagnosis of chronic chagasic cardiopathy can be considered with a low probability in the absence of this factor.