Control of Toxoplasma gondii infection by athymic LEW-Whn rnu rats.
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.
Sepulveda-Arias
J C
JC
Institute for Virology and Immunobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany.
Kempf
M C
MC
Wiehr
S
S
Wedekind
D
D
Hedrich
H J
HJ
Gross
U
U
Herrmann
T
T
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000918:Antibody Specificity; D000953:Antigens, Protozoan / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D020022:Genetic Predisposition to Disease; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D008214:Lymphocytes / Q000502:physiology; D051381:Rats; D011916:Rats, Inbred F344 / Q000276:immunology; D011917:Rats, Inbred Lew / Q000276:immunology*; D011923:Rats, Nude / Q000276:immunology*; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000097:blood / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma