Control of Toxoplasma gondii infection by athymic LEW-Whn rnu rats

Parasite Immunol. Jun-Jul 2008;30(6-7):323-33. doi: 10.1111/j.1365-3024.2008.01029.x. Epub 2008 Apr 21.

Abstract

In immunocompetent rats and humans infection with Toxoplasma gondii remains mostly without overt clinical symptoms, but can be fatal, if the T-cell response is impaired. For a better understanding of the lack of control of T. gondii infection under immunosuppressed conditions, congenitally athymic rats were used as the experimental model. Whereas athymic F344-Whn(rnu) (F344 nude) rats die from a generalized infection during the first 3 weeks after peritoneal inoculation with 10(6) tachyzoites of T. gondii strain NTE, LEW-Whn(rnu) (LEW nude) rats and euthymic LEW rats infected with a 10-fold higher number of parasites developed chronic infection. To identify underlying mechanisms of LEW rats resistance to T. gondii infection and to investigate a possible contribution of residual T-cells to LEW-Whn(rnu) rat resistance, we characterized the immune response of LEW rats by determination of cellularity and composition of lymphocyte population, antigen-specific IgG2b response as well as assays of antigen-specific proliferation and production of IL-2, IFN-gamma and TNF-alpha. As only euthymic LEW rats developed production of antigen-specific IgG and cellular in vitro responses, these results strongly suggest that the genetic background of LEW rats permits a control of the infection independent of an adaptive immune response.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Antibodies, Protozoan / blood
  • Antibody Specificity
  • Antigens, Protozoan / immunology
  • Cell Proliferation
  • Cells, Cultured
  • Genetic Predisposition to Disease
  • Immunoglobulin G / blood
  • Interferon-gamma / immunology
  • Interleukin-2 / immunology
  • Lymphocytes / physiology
  • Rats
  • Rats, Inbred F344 / immunology
  • Rats, Inbred Lew / immunology*
  • Rats, Nude / immunology*
  • Toxoplasma / immunology*
  • Toxoplasmosis / blood
  • Toxoplasmosis / immunology*
  • Tumor Necrosis Factor-alpha / immunology

Substances

  • Antibodies, Protozoan
  • Antigens, Protozoan
  • Immunoglobulin G
  • Interleukin-2
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma