SUMMARY OF THESIS^*

LESCANO, Susana Angélica Zevallos - Toxocara canis: resposta de anticorpos IgG na infecção murina experimental e na co-infecção com outros parasitos. São Paulo, 1998. (Tese de Doutoramento - Instituto de Ciências Biomédicas da Universidade de São Paulo).

Toxocara canis : IgG ANTIBODY RESPONSE IN EXPERIMENTAL MURINE INFECTION AND IN COINFECTIONS WITH OTHER PARASITES.

The antibody response of IgG class was studied in BALB/c mice infected by Toxocara canis in two different situations. In the first one, with the aim of verifying in vivo possible cross-reactions between Toxocara canis and other parasites (Ascaris suum, Taenia crassiceps, Schistosoma mansoni, Strongyloides venezuelensis and Toxoplasma gondii) experiments with three groups of mice were done: one infected only by Toxocara canis, another by one of the other species and a third one concomitantly infected by Toxocara canis and the species at issue. All animals were bled by the retroorbital plexus at 23, 38 and 70 days post infection. Sera were tested for the presence of anti- Toxocara antibodies by ELISA and Immunoblotting, using Excretory-Secretory (ES) antigen obtained from Toxocara canis second stage larvae culture. In all experiments a negative control group with 10 uninfected animals was used.

A second situation to study the antibody response of BALB/c mice infected by Toxocara canis tried to establish if anthelmintics administration did alter anti-Toxocara antibodies production, in a period up to 120 days after therapy. Three groups of mice had been infected by 300 Toxocara canis eggs. One group stayed untreated and the other two were treated with thiabendazole or albendazole during 10 days. A fourth group of uninfected animals was the negative control. Mice were bled 23,38,70, 85, 100 and 120 days after the outset of treatment and sera were analyzed by ELISA and Immunoblotting as before.

Only in the infections by Ascaris suum had been found, in our experimental conditions, cross reactivity with antigens of Toxocara canis. However, in Toxocara canis- Schistosoma mansoni, Toxocara canis Strongyloides venezuelensis and Toxocara canis - Taenia crassiceps coinfections it was confirmed production of anti-Toxocara antibodies at levels significantly lower than those found in the mice infected only with Toxocara canis. In coinfections either by Schistosoma mansoni or Strongyloides venezuelensis it was also observed lower lethality rate when compared with that of animals with single infections. The antibody response determined in mice treated with thiabendazole or albendazole and in the untreated group did not reveal significative differences, indicating impossibility of therapy evaluation using these techniques. Nevertheless, by means of larval recovery after homogenization of CNS of mice, it was possible to perceive significative decrease in the number of larvae in thiabendazol treated animals.

*

This thesis is available at the Library of the Instituto de Medicina Tropical de São Paulo.

Publication Dates

• Publication in this collection
  01 Mar 1999
• Date of issue
  Nov 1998